Life: Life is the characteristic that distinguishes living matter from non-living matter. It involves biological processes, such as self-sustaining activities and signaling. Life is defined by its ability to maintain homeostasis, organize itself, metabolize, grow, adapt, respond to stimuli, and reproduce. Defining living systems, like viruses, can be challenging as they can only reproduce within host cells. Life exists all over Earth in air, water, and soil, with diverse ecosystems forming the biosphere. Some of these environments are extreme, hosting only extremophiles.

Death: Death is the end of all biological functions in an organism, including the brain, and decomposition follows shortly thereafter. It is an inevitable process that occurs in all organisms, but a few exceptions exist. Turritopsis dohrnii is biologically immortal but can still die from causes other than aging.

Suicide: Suicide is the intentional act of causing one's own death. Risk factors include mental disorders, physical disorders, and substance abuse. It can result from impulsivity due to stress, relationship problems, or harassment. Prior suicide attempts increase the likelihood of future attempts. Prevention efforts involve restricting access to lethal means, treating mental disorders and substance abuse, improving economic conditions, and using dialectical behaviour therapy. The effectiveness of crisis hotlines remains understudied.

Abiogenesis: Abiogenesis is the natural process where life originates from non-living materials. It involves the formation of a habitable planet, the synthesis of organic molecules, molecular self-replication, self-assembly, and the emergence of cell membranes. However, the transition from non-life to life has not been observed experimentally.

Organism: An organism is a living system composed of cells and functions as an individual life form. It is the minimal functional unit of life and possesses traits such as noncompartmentability, individuality, and distinctness. These traits involve the organism's structure, genetic uniqueness, autonomy, and open-system genetic information.

Model organism: A model organism is a non-human species studied extensively to unlock biological secrets that can provide insights into other organisms. They are particularly useful in researching human diseases when ethical or practical considerations prevent direct human experimentation. This is made possible by the shared heritage and conservation of genes and developmental processes across evolution.

Biology: Biology is the study of life, encompassing the understanding of cells, genetics, evolution, energy processing, and organism regulation. It explores the unity and diversity of living organisms, highlighting their interconnectedness and ability to transmit hereditary information across generations.

Microbiology: Microbiology is the study of microorganisms, including single-celled, multicellular, and acellular forms. It encompasses sub-disciplines such as virology, bacteriology, protistology, mycology, immunology, and parasitology.

Mycology: Mycology is the study of fungi, covering topics like taxonomy, genetics, biochemical properties, and their various uses by humans. Fungi serve as a source of tinder, food, traditional medicine, entheogens, poison, and can cause infections.

Evolution: Evolution is the process of heritable changes in biological populations over time. It is driven by factors like natural selection and genetic drift, which act on genetic variations. As a result, certain traits become more or less common in a population over generations. This process has led to the diversity of life at all levels of biological organization.

History of life: The history of life on Earth involves the evolution of living and fossil organisms, starting from the earliest emergence of life till present day. Earth formed about 4.5 billion years ago and evidence suggests that life emerged before 3.7 billion years ago. Some controversy remains regarding possible non-biological formation of early fossils.

Neuroscience: Neuroscience is the scientific study of the nervous system and its functions, incorporating various disciplines such as anatomy, physiology, psychology, and molecular biology. It seeks to understand the fundamental properties of neurons, glia, and neural circuits, with an emphasis on learning, memory, behavior, perception, and consciousness. This field presents a significant challenge in the biological sciences.

Sense: A sense is a biological system that helps organisms gather information about the world through the detection of stimuli. While traditionally five human senses were identified, more senses are now recognized. Non-human organisms have even greater variety of senses. Sense organs collect stimuli and transform them into a form that can be understood by the brain. Sensation and perception are vital for an organism's cognition, behavior, and thought.

Amber: Amber is fossilized tree resin admired for its color and beauty since ancient times. It serves as a gemstone and is crafted into various decorative items. People also use amber in jewelry and traditional medicine for healing purposes.

Ivory: Ivory is a hard, white material made from the teeth and tusks of animals. It consists mainly of dentine, the physical structure of teeth and tusks. Ivory contains mineralized collagen structures. The trade in teeth and tusks other than elephant is widespread, so "ivory" can describe any mammalian teeth or tusks of commercial interest that are large enough for carving or scrimshawing.

Pearl: A pearl is a hard, glistening object formed inside the soft tissue of certain animals. It consists of calcium carbonate deposited in concentric layers, and can be round or baroque in shape. Natural pearls are highly valued gemstones due to their rarity and beauty, symbolizing something valuable and admirable.

Paleontology: Paleontology is the scientific study of life before and during the Holocene epoch. It involves classifying organisms based on fossils and understanding their interactions in past environments. The term originated in 1822 from the Greek words for "old," "being," and "study." The field traces its history back to ancient times and gained prominence in the 18th and 19th centuries thanks to Georges Cuvier's work on comparative anatomy.

Fossil: A fossil is the preserved remains or traces of a past living organism from a geological age. They can include bones, shells, imprints, and even DNA remnants. Fossils collectively make up the fossil record.

Phylogenetics: Phylogenetics is the study of the evolutionary history and relationships between groups of organisms. It uses different methods, like analyzing DNA sequences or morphology, to create a phylogenetic tree that represents the evolutionary history of a group.

Binomial nomenclature: Binomial nomenclature is a formal naming system in taxonomy that assigns a two-part Latin-based name to each species. This scientific name, also known as a binomen, consists of a genus and a specific epithet. It is widely used to classify living organisms and is sometimes referred to as a Latin name. The system is called binominal nomenclature and is recognized by the International Commission on Zoological Nomenclature (ICZN).

Taxonomy (biology): Taxonomy is the scientific study of naming and classifying living organisms based on their shared characteristics. It involves grouping organisms into categories called taxa and organizing them in a hierarchical manner. Carl Linnaeus, a Swedish botanist, is considered the founder of modern taxonomy, developing a system known as Linnaean taxonomy for categorizing and naming organisms using a binomial nomenclature.

Domain (biology): In biology, a domain is the highest taxonomic rank that categorizes all organisms. It was introduced in the three-domain system by Woese, Kandler, and Wheelis in 1990.

Kingdom (biology): In biology, a kingdom is a high taxonomic rank, below domain. It categorizes organisms into groups known as phyla.

Species: A species is the largest group of organisms that can successfully reproduce and produce fertile offspring. It is an essential unit for classification, biodiversity, and understanding an organism. Species can be defined by various factors such as genetics, physical traits, behavior, or ecological role. Paleontologists rely on the concept of chronospecies when studying fossils.

Biomechanics: Biomechanics is the study of the mechanics of living organisms, including their structure, function, and motion. It examines biological systems at various levels, from whole organisms down to cells and organelles. Applying the principles of mechanics, biomechanics is a field within biophysics.

Anatomy: Anatomy is the study of the structure of organisms and their parts. It is an old science with roots in prehistoric times. This branch of natural science is closely tied to developmental biology, embryology, comparative anatomy, evolutionary biology, and phylogeny. Anatomy and physiology are related disciplines that explore the structure and function of organisms and their parts. Human anatomy is a fundamental science used in medicine.

Dissection: Dissection is the act of studying the anatomical structure of a deceased animal or plant by dismembering its body. Autopsies are used to determine the cause of death in humans. It is commonly taught in middle school and high school biology classes using preserved plants and small animals, while medical students perform extensive dissections on fresh and preserved human cadavers in subjects like anatomy, pathology, and forensic medicine. Dissections are usually conducted in morgues or anatomy labs.

Organ (biology): An organ in biology consists of different types of tissues that work together to carry out a specific function. It serves as a structural unit between tissues and organ systems. Tissues are made up of the same type of cells, while organs are formed by combining different types of tissues. Organ systems are created when two or more organs collaborate to perform a particular function in the body.

Tissue (biology): Tissue, in biology, exists between cells and organs, comprised of cells and their extracellular matrix with a shared function and embryonic origin. Multiple tissues combine to form organs.

Sexual dimorphism: Sexual dimorphism refers to the differences in physical traits or behaviors between males and females of the same species, which are not directly related to reproduction. This condition is common in most animals and some plants. Examples of these differences may include size, weight, color, markings, or cognitive traits. Competition for reproduction has led to the evolution of various sexually dimorphic traits, like aggressive utility traits used as weapons or passive displays for attracting mates. These differences can be subtle or pronounced and are influenced by both sexual and natural selection. In contrast, monomorphism occurs when both sexes have similar physical characteristics.

Head: A head is the main part of an organism containing ears, brain, forehead, cheeks, chin, eyes, nose, and mouth. It aids in functions like sight, hearing, smell, and taste. Although simple animals may lack a head, many symmetric forms have one regardless of size.

Thorax: The thorax is a part of the human and animal anatomy located between the neck and abdomen. It is the middle division of the body in insects, crustaceans, and extinct trilobites, made up of multiple segments.

Abdomen: The abdomen is the body part between the chest and pelvis in humans and other vertebrates. It is the front section of the torso's abdominal segment and contains the abdominal cavity. In arthropods, it is the posterior body tagma following the thorax or cephalothorax.

Circulatory system: The circulatory system, also known as the cardiovascular system or vascular system, is a network of organs, including the heart, blood vessels, and blood, that circulates throughout the body. It consists of two circuits: the systemic circulation, responsible for supplying oxygen and nutrients to all tissues, and the pulmonary circulation, which transports oxygen-depleted blood to the lungs for oxygenation. The terms cardiovascular and vascular systems are often used interchangeably with the circulatory system.

Blood: Blood is a crucial body fluid in humans and other vertebrates that carries nutrients and oxygen to cells and removes waste products. It is referred to as peripheral blood and contains peripheral blood cells.

Red blood cell: Red blood cells (RBCs), or erythrocytes, are the most abundant type of blood cell. They deliver oxygen to tissues through the circulatory system by taking it up in the lungs (or gills in fish) and releasing it while passing through capillaries. RBCs lack a nucleus and are also known as red cells or haematids. Their scientific name is derived from the Greek words for red and hollow vessel.

White blood cell: White blood cells (leukocytes) are immune cells that defend the body against infections and foreign agents. They comprise granulocytes, lymphocytes, and monocytes as the main subtypes.

Artery: Arteries are blood vessels that carry oxygenated blood away from the heart to different parts of the body. However, there are exceptions like the pulmonary arteries, which carry deoxygenated blood to the lungs for oxygenation, and the umbilical arteries, which transport deoxygenated blood to the placenta in fetal circulation.

Capillary: Capillaries are the smallest blood vessels in the body, only 5 to 10 micrometers in diameter. They consist of a thin wall made of simple squamous endothelial cells and are part of the microcirculation system. Capillaries allow for the exchange of substances between the blood and surrounding interstitial fluid. They carry blood from small arteries to small veins and facilitate the passage of various substances such as water, oxygen, carbon dioxide, and waste products. Lymph capillaries connect with larger lymph vessels to drain lymphatic fluid from the microcirculation system.

Vein: Veins are blood vessels that carry blood towards the heart in the circulatory system. They mostly transport deoxygenated blood from tissues back to the heart, except for pulmonary and fetal circulations which carry oxygenated blood to the heart. Arteries carry oxygenated blood away from the heart, while veins return deoxygenated blood to the heart in the deep veins.

Heart: The heart is a muscular organ that pumps blood through blood vessels, supplying oxygen and nutrients to the body and removing metabolic waste. It is roughly the size of a closed fist and is located in the middle compartment of the chest, known as the mediastinum.

Lymphatic system: The lymphatic system is an organ system in vertebrates that is part of the immune system and complements the circulatory system. It includes a network of lymphatic vessels, lymph nodes, and organs, as well as lymph fluid. Lymph fluid is a clear liquid that is transported back to the heart for recirculation. The word "lympha" refers to the deity of fresh water in Latin.

Spleen: The spleen, present in most vertebrates, functions as a blood filter. It resembles a large lymph node and its name is derived from the Ancient Greek word "σπλήν (splḗn)."

Endocrine system: The endocrine system is a messaging system in organisms where hormones are released by glands into the bloodstream to regulate distant organs. In vertebrates, the hypothalamus controls all endocrine systems.

Adrenal gland: The adrenal gland is an endocrine gland that produces hormones, such as adrenaline, aldosterone, and cortisol. Located above the kidneys, it consists of an outer cortex that produces steroid hormones and an inner medulla. The adrenal cortex is further divided into three zones: the zona glomerulosa, the zona fasciculata, and the zona reticularis.

Thyroid: The thyroid is an endocrine gland in vertebrates located in the neck, consisting of two connected lobes with an isthmus. It secretes three hormones: triiodothyronine (T3), thyroxine (T4), and calcitonin. These hormones regulate metabolism, protein synthesis, growth, and development in children, as well as calcium homeostasis. The thyroid is regulated by thyroid-stimulating hormone (TSH) from the anterior pituitary gland, which is in turn regulated by thyrotropin-releasing hormone (TRH) from the hypothalamus.

Mouth: The mouth is an orifice used by animals to eat and communicate. It is part of the oral cavity, which connects to the pharynx and nutrients pass through it. Invertebrates have lips and cheeks that bound the mouth, sometimes referred to as the buccal cavity, and a tongue inside. Most vertebrates possess teeth in their mouth, although some fish have teeth in their throat instead.

Esophagus: The esophagus is a tube in vertebrates that carries food from the throat to the stomach. It is about 25 cm long, located behind the trachea and heart, and passes through the diaphragm. Peristaltic contractions help move food along the esophagus. During swallowing, the epiglottis prevents food from entering the larynx and lungs. The word "esophagus" comes from Ancient Greek, meaning "to carry" + "I ate."

Liver: The liver is a vital organ found in vertebrate animals, including humans. It plays a crucial role in detoxification, protein synthesis, and digestion. It is located in the upper right abdomen, protected by the ribs. The liver also manages carbohydrate metabolism, hormone production, nutrient storage, and the breakdown of red blood cells.

Large intestine: The large intestine, or large bowel, is the final segment of the digestive system in animals with four limbs. It absorbs water and stores waste material in the rectum as feces before elimination through defecation. The colon is the longest part of the large intestine, and it is often used to refer to the entire large intestine, including the cecum, colon, rectum, and anal canal. However, some sources exclude the anal canal.

Small intestine: The small intestine is a vital organ in the gastrointestinal tract that absorbs nutrients from food. It receives bile and pancreatic juice to aid in digestion and is about 5.5 meters long, folding multiple times to fit in the abdomen. Despite its length, it is called "small" because it is narrower than the large intestine.

Pancreas: The pancreas is an organ in the abdomen behind the stomach. It acts as a gland with both endocrine and digestive functions. It regulates blood sugar levels by secreting insulin, glucagon, somatostatin, and pancreatic polypeptide. Additionally, it produces pancreatic juice containing bicarbonate and digestive enzymes to neutralize stomach acid and break down food in the duodenum.

Stomach: The stomach is a crucial part of the digestive system, found in humans and other animals. It is a muscular, hollow organ that aids in digestion by breaking down food using enzymes and hydrochloric acid. The stomach plays a major role in the gastric phase of digestion after chewing.

Immune system: The immune system is a biological network that protects organisms from diseases by detecting and responding to a range of pathogens. It also recognizes and eliminates abnormal cells and objects. It has two major subsystems: the innate immune system, which has a preconfigured response to general situations, and the adaptive immune system, which learns to recognize specific molecules encountered before. Both subsystems use molecules and cells to carry out their functions.

Antibody: An antibody, also known as an immunoglobulin, is a large protein used by the immune system to identify and neutralize foreign objects like bacteria and viruses. It recognizes unique molecules on pathogens and binds to them with precision. This binding allows the antibody to tag the pathogen for attack by the immune system or neutralize it directly.

Integumentary system: The integumentary system includes an animal's skin and its appendages. It acts as a physical barrier, protecting and maintaining the body from the external environment. It is mainly the outer skin of the body.

Breast: The breast is a prominence found on the upper ventral region of a primate's torso. It develops in both females and males from the same embryological tissues.

Feather: Feathers are unique, epidermal growths on birds and certain dinosaurs. They make up a complex outer covering known as plumage. Feathers are the most complex integumentary structures in vertebrates and an important characteristic of birds that sets them apart from other living groups.

Fingerprint: A fingerprint is a mark formed by the ridges on a human finger. It is important in forensic science for identifying individuals. Fingerprints are left on surfaces when the finger is moist or greasy. Ink or other substances can be used to create a complete fingerprint on a smooth surface. Fingerprints are typically obtained from the pad on the last joint of fingers and thumbs, and sometimes from lower joint areas of the fingers.

Fur: Fur is the hair covering the skin of mammals, comprising of oily guard hair on top and insulating underfur beneath. It protects against moisture and provides warmth.

Hair: Hair is a protein filament that grows from follicles in the skin. It is a defining characteristic of mammals. Besides areas of smooth skin, the entire human body is covered in follicles that produce thick and fine hair. Apart from its growth and types, hair is a crucial protein-based biomaterial composed mainly of alpha-keratin.

Nail (anatomy): Nails are protective plates found at the tips of primate digits, similar to claws in other animals. They are composed of a tough protein called alpha-keratin, also found in the claws, hooves, and horns of vertebrates.

Scale (anatomy): Scales, found in zoology, are small protective plates that grow from an animal's skin. They also serve as coloration plates on the wings of lepidopterans (insects). Scales are widespread, having evolved independently multiple times through convergent evolution, showcasing different structures and functions.

Skin: Skin is a vital layer of tissue that covers the body of vertebrate animals. It serves three main purposes: safeguarding, regulating, and enabling sensation.

Muscular system: The muscular system consists of skeletal, smooth, and cardiac muscles that enable body movement, maintain posture, and circulate blood. It is controlled by the nervous system and, along with the skeletal system, forms the musculoskeletal system responsible for body movement.

Muscle cell: A muscle cell, or myocyte, is a mature cell in animal muscles. Humans have three types: skeletal, smooth, and cardiac. Skeletal muscle cells, also known as muscle fibers, are long and have multiple nuclei. They develop from embryonic myoblast precursor cells.

Sarcomere: A sarcomere is the fundamental unit of muscle tissue, connecting two Z-lines. It is composed of filaments that slide past each other during muscle movement. Sarcomeres make up myofibrils, which are the building blocks of muscle fibers. They are recognizable under a microscope as alternating dark and light bands. The costamere is a separate structure that links the sarcomere to the sarcolemma.

Skeletal muscle: Skeletal muscles, organs of the vertebrate muscular system, are attached to bones by tendons. They consist of long muscle cells known as fibers and have a striated appearance due to the arrangement of sarcomeres.

Nervous system: The nervous system is a complex part of an animal that coordinates actions and senses environmental changes. It consists of the central nervous system (brain and spinal cord) and the peripheral nervous system (nerves). The peripheral nervous system has somatic, autonomic, and enteric subsystems. The autonomic system has sympathetic and parasympathetic branches, while the enteric system controls the gastrointestinal system. The nervous system arose about 550 to 600 million years ago in wormlike organisms. It uses motor and sensory nerves to transmit signals and is divided into cranial and spinal nerves.

Central nervous system: The central nervous system (CNS) includes the brain, spinal cord, retina, optic nerve, and olfactory nerve and epithelia. It integrates information, influences body activity, and is present in bilaterally symmetric animals. It is composed of nervous tissue along the body axis with an enlarged section at the rostral end called the brain. Only arthropods, cephalopods, and vertebrates have a true brain, but precursor structures exist in other organisms.

Peripheral nervous system: The Peripheral Nervous System (PNS) is the part of the nervous system that connects the brain and spinal cord to the rest of the body. It includes nerves and ganglia located outside the brain and spinal cord. Its primary function is to relay information between the central nervous system and organs and limbs. Unlike the central nervous system, the PNS is not protected by the vertebral column, skull, or blood-brain barrier, making it vulnerable to toxins.

Brain: The brain is a central organ in the nervous system that controls various bodily functions. It is the largest cluster of neurons in the body and is typically located in the head. The brain regulates endocrine systems, processes sensory information, controls movement, and contributes to intelligence development.

Brainstem: The brainstem is the part of the brain connecting the cerebrum and diencephalon with the spinal cord. It consists of the midbrain, pons, and medulla oblongata. The midbrain is connected to the thalamus.

Cerebellum: The cerebellum is a key part of the hindbrain in all vertebrates. It is smaller than the cerebrum but plays a crucial role in motor control. It may also be involved in attention, language, and emotion regulation. The cerebellum receives sensory input and coordinates fine motor activity. Damage to the cerebellum can lead to disorders in movement and motor learning.

Cerebral cortex: The cerebral cortex is the outer layer of neural tissue in the brain, consisting mostly of the six-layered neocortex. It is divided into two cortices by the longitudinal fissure and joined by the corpus callosum. It is the largest site of neural integration in the central nervous system and plays a crucial role in cognition, including attention, perception, memory, language, and consciousness.

Cerebrum: The cerebrum is the largest part of the brain, located at the uppermost region of the central nervous system. It includes the cerebral cortex and subcortical structures like the hippocampus, basal ganglia, and olfactory bulb. The cerebrum develops from the forebrain and is divided into left and right cerebral hemispheres.

Neuron: A neuron is an electrically excitable cell that transmits electric signals called action potentials through a neural network. It communicates with other cells through synapses, using neurotransmitters to transmit signals between cells.

Spinal cord: The spinal cord is a long, tubular structure made of nervous tissue that extends from the brainstem to the lower back. It is hollow and contains cerebrospinal fluid, covered by meninges and enclosed by neural arches. Along with the brain, it forms the central nervous system.

Sensory nervous system: The sensory nervous system processes sensory information and consists of sensory neurons, neural pathways, and the brain. It includes senses such as vision, hearing, touch, taste, smell, balance, and visceral sensation. Sense organs convert data to the mind, allowing people to interpret and perceive the outside world.

Auditory system: The auditory system is responsible for the sense of hearing. It comprises the sensory organs and the auditory parts of the sensory system.

Ear: The ear is the organ responsible for hearing and body balance. It consists of three parts: the outer ear, middle ear, and inner ear. The outer ear includes the pinna and ear canal. The middle ear contains the tympanic cavity and ossicles. The inner ear contains structures like the semicircular canals, utricle, saccule, and cochlea, which enable balance, eye tracking, and hearing. The ear is self-cleaning through the production of earwax. Ears are placed symmetrically on each side of the head, aiding sound localization.

Hearing: 'Hearing' refers to the ability to detect sounds through an ear by perceiving vibrations as changes in surrounding medium pressure. The academic discipline dedicated to studying hearing is auditory science.

Taste: Taste is the sense responsible for flavor perception. It occurs when chemicals in the mouth react with taste receptors on taste buds, mostly on the tongue. Along with smell and nerve stimulation, taste determines food flavors. Humans have taste receptors on taste buds, tongue, and epiglottis. The gustatory cortex is responsible for taste perception.

Tongue: The tongue is a muscular organ in the mouth that aids in chewing, swallowing, and tasting food. It is covered by taste buds and lingual papillae, and is moistened by saliva. The tongue is essential for speech and vocalization and also helps to clean teeth.

Olfactory system: The olfactory system is responsible for the sense of smell. It is a sensory system found in mammals and reptiles. It has two parts: the main olfactory system, which detects airborne substances, and the accessory olfactory system, which senses fluid-phase stimuli.

Nose: A nose is a protrusion in vertebrates that houses the nostrils, which take in and expel air for respiration. It is located centrally on the face in humans and serves as an alternate respiratory passage during infancy. The nose also contains the olfactory mucosa and sinuses, and air passes through the nasal cavity into the rest of the respiratory system. The distinctive separate protruding nose found in therian mammals evolved from the upper jaw of reptilian-like ancestors.

Sense of smell: The sense of smell, or olfaction, detects smells and has various functions like identifying food, dangers, and pheromones. It also plays a part in the sense of taste.

Somatosensory system: The somatosensory system is a network of neural structures that allows us to perceive touch, temperature, body position, and pain. It is part of the sensory nervous system which also encompasses other senses like vision, hearing, smell, taste, and balance.

Pain: Pain is a distressing feeling caused by intense or damaging stimuli. It is an unpleasant sensory and emotional experience associated with actual or potential tissue damage, as defined by the International Association for the Study of Pain.

Visual system: The visual system is the combination of the sensory organ and parts of the central nervous system that enable organisms to see and perceive their environment. It detects and interprets information from the visible spectrum to form a representation of the surroundings. The visual system performs various tasks, including light reception, color vision, depth perception, object identification, motion perception, and visual information integration. It also encompasses visual perception, which involves the processing of visual information, and visual impairment or blindness in case of abnormalities. Additionally, it includes non-image forming functions like the pupillary light reflex and circadian photoentrainment.

Eye: Eyes are organs that provide living organisms with vision and the ability to process visual detail. They detect and convert light into electro-chemical impulses in neurons. In higher organisms, eyes are complex systems that collect and regulate light, focus it through lenses to create images, convert images into electrical signals, and transmit these signals to the brain. Different species have various types of eyes, with image-resolving eyes found in molluscs, chordates, and arthropods.

Visual perception: Visual perception is the interpretation of the environment through various types of vision, such as color, low light, and normal vision. It involves processing visible light reflected by objects. This is distinct from visual acuity, which measures clarity of vision. People can experience difficulties with visual perception despite having good eyesight.

Color vision: Color vision is the ability to perceive differences in light frequencies regardless of intensity. It is mediated by a complex process involving neurons and photoreceptors in the visual system. This ability is found in various animals and is influenced by evolutionary history. In primates, color vision has evolved for tasks such as finding food, detecting camouflage, and recognizing emotional states in other primates.

Reproductive system: The reproductive system, also called genital system, consists of organs involved in sexual reproduction. It includes fluids, hormones, and pheromones. Differentiated species exhibit significant sexual differences, enabling genetic material exchange and potentially enhancing offspring's genetic fitness.

Sex organ: Sex organs, also called reproductive organs, are involved in sexual reproduction. They are responsible for producing and transporting gametes, facilitating fertilization, and supporting the development and birth of offspring. Found in various species, their features vary depending on the species.

Female reproductive system: The female reproductive system consists of internal and external sex organs involved in reproducing offspring. It develops from immaturity at birth to maturity during puberty. Internal organs include the vagina, uterus, fallopian tubes, and ovaries, which can be susceptible to infections. The vagina facilitates sexual intercourse and childbirth, connecting to the uterus. The uterus supports embryo development and produces secretions to aid sperm transport to the fallopian tubes, where fertilization occurs. External sex organs, known as the vulva, include the labia, clitoris, and vaginal opening.

Clitoris: The clitoris is a female sex organ found in mammals, ostriches, and a few other animals. In humans, it is located at the front junction of the labia minora, above the urethral opening. Unlike the male penis, the clitoris does not contain the distal portion of the urethra and is not used for urination. It usually lacks reproductive function in most species, but the spotted hyena has a large clitoris used for urination, mating, and giving birth. Some other mammals, like lemurs and spider monkeys, also have a large clitoris.

Ovary: The ovary is a female reproductive organ that produces eggs and releases them into the fallopian tube. It is found on both sides of the body and secretes hormones that regulate the menstrual cycle and fertility. The ovary undergoes changes from prenatal development to menopause and functions as an endocrine gland by producing different hormones.

Placenta: The placenta is a temporary organ that develops during pregnancy. It facilitates exchange of nutrients, gases, and waste between mother and fetus. It also produces hormones that regulate both maternal and fetal physiology. It connects to the fetus via the umbilical cord and is expelled from the uterus after birth. Placentas are found in placental mammals, marsupials, and some non-mammals with varying levels of development.

Uterus: The uterus is a vital organ in the female reproductive system, responsible for supporting the development of embryos and fetuses until birth. It is a hormone-responsive sex organ that produces uterine milk to nourish the developing embryos.

Vagina: The vagina is a flexible, muscular part of the female reproductive system in mammals. In humans, it stretches from the vestibule to the cervix and is partially covered by the hymen. The cervix protrudes into the vagina, allowing for sexual intercourse and childbirth. Additionally, it facilitates menstrual flow during the menstrual cycle of humans and related primates.

Male reproductive system: The male reproductive system comprises external and internal sex organs involved in human reproduction, located both outside the body and within the pelvis.

Penis: A penis is a male sexual organ found in many animals, used for inseminating females during copulation. It exists in both vertebrates and invertebrates, but not in all species. Additionally, penises may not have common ancestry.

Testicle: A testicle is the male gonad responsible for producing sperm and testosterone. It is equivalent to the female ovary. Testosterone release is regulated by luteinizing hormone from the anterior pituitary, while sperm production is controlled by both follicle-stimulating hormone and gonadal testosterone.

Respiratory system: The respiratory system is a biological system for gas exchange in animals and plants. It consists of organs like the lungs, which contain millions of small air sacs called alveoli or atria. These sacs have a rich blood supply and communicate with the external environment through airways, such as the trachea and bronchioles. Breathing pumps air into the alveoli or atria, facilitated by the muscles of respiration.

Gill: A gill is a respiratory organ used by aquatic organisms to extract oxygen from water and release carbon dioxide. Some species, like hermit crabs, can adapt their gills to respire on land when moist. Gills provide a large surface area for gas exchange and are also known as branchia in zoology.

Lung: The lungs are vital organs in the respiratory system that extract oxygen from the air and release carbon dioxide. They are located near the backbone and work to facilitate gas exchange in humans and most animals. The pleurae reduce friction during breathing, enabling effortless movement of the lungs.

Skeleton: A skeleton is a structural frame that supports the body of animals. It can be classified into three types: exoskeleton, which is a rigid outer shell; endoskeleton, a rigid internal frame; and hydroskeleton, a flexible internal structure supported by body fluids.

Bone: Bones are rigid organs found in vertebrate animals, serving to protect organs, produce blood cells, store minerals, provide support and structure, enable movement, and possess complex internal and external structures. They are lightweight, strong, and versatile, fulfilling multiple essential functions.

Jaw: Jaws are opposable structures at the entrance of the mouth used for grasping and manipulating food. They are part of the body plan of humans and most animals, constituting the vault of the mouth and enabling its opening and closing.

Joint: A joint is the connection between bones or other hard structures in the body, allowing for different types of movement. Some joints, like the knee and shoulder, are self-lubricating and can handle heavy loads while moving smoothly. Other joints, such as those in the skull, have limited movement to protect the brain and sense organs. Joints can be classified structurally and functionally.

Pelvis: The pelvis is the lower part of the trunk, containing the embedded skeleton and located between the abdomen and thighs.

Skull: The skull is a protective bone cavity for the brain, consisting of cranial bones, facial bones, ear ossicles, and the hyoid bone. The cranium and the mandible are the most noticeable parts. It is located at the front of the skeleton and is responsible for housing the brain and sensory structures like the eyes, ears, nose, and mouth. In humans, these sensory structures are part of the facial skeleton.

Vertebral column: The vertebral column, or backbone, is the main part of the skeleton in vertebrate animals. It consists of a series of segmented bones called vertebrae that replace the notochord found in all chordates. These vertebrae are separated by fibrocartilaginous discs. The dorsal part of the vertebral column contains the spinal canal, which protects the spinal cord.

Connective tissue: Connective tissue is a primary animal tissue that develops from the mesenchyme. It is found throughout the body, including the nervous system and meninges. Composed of various components, it includes elastic and collagen fibers, ground substance, and cells. Specialized fluid connective tissues like blood and lymph are also considered part of connective tissue. Common cell types found in connective tissue are fibroblasts, adipocytes, macrophages, mast cells, and leucocytes.

Cartilage: Cartilage is a resilient and smooth connective tissue, covered by the perichondrium membrane. It protects bones at joints and is found in body parts like the rib cage and intervertebral discs. It is less flexible than muscle and harder than bone. The matrix of cartilage contains glycosaminoglycans, proteoglycans, collagen fibers, and sometimes elastin. It grows faster than bone.

Tendon: A tendon is a strong and flexible connective tissue that links muscles to bones, carrying the force from muscle contractions to the skeletal system.

Epithelium: Epithelium is a protective layer of tightly packed cells without much space in between. It lines the outer surfaces of organs, blood vessels, and inner cavities. The epidermis, which is the outer layer of the skin, is an example of epithelial tissue. It is one of the four basic types of animal tissue, along with connective tissue, muscle tissue, and nervous tissue. Epithelial tissue lacks blood or lymph supply but is supported by nerves.

Muscle: Muscle is a type of soft tissue found in animals that allows for movement. It is formed during embryonic development and contains contractile proteins like actin and myosin, which enable muscle contractions. Additionally, muscle tissue includes regulatory proteins like troponin and tropomyosin.

Nervous tissue: Nervous tissue, or neural tissue, is the primary component of the nervous system. It regulates and controls body functions through two parts: the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain and spinal cord, while the PNS includes the branching peripheral nerves. This tissue is composed of neurons, or nerve cells, which receive and transmit impulses, and neuroglia, or glial cells, which aid in impulse propagation and provide nutrients to neurons.

Bladder: The bladder is a hollow organ that stores urine before it is eliminated through urination. It is distensible and located on the pelvic floor. Urine enters through the ureters and exits through the urethra. An average adult bladder holds around 300 to 500 ml of urine.

Kidney: The kidneys are reddish-brown bean-shaped organs that filter blood in humans. They are located in the retroperitoneal space, about 12 centimetres in length. Each kidney is connected to a ureter, which carries urine to the bladder.

Urinary system: The urinary system, or urinary tract, includes the kidneys, ureters, bladder, and urethra. It eliminates waste, regulates blood volume and pressure, controls electrolyte and metabolite levels, and maintains blood pH. The kidneys filter blood and produce urine, which is carried by the ureters to the bladder for storage and excretion through urination. The male and female urinary systems differ only in urethra length.

Plant anatomy: Plant anatomy is the study of the internal structure of plants. It used to include plant morphology, but now focuses solely on internal plant structure. This field explores plant anatomy at the cellular level using tissue sectioning and microscopy techniques.

Plant morphology: Plant morphology is the study of a plant's physical form and external structure. It helps in visually identifying plants and is distinct from plant anatomy, which focuses on internal structure. Recent molecular biology studies have explored the molecular processes that determine plant morphology, including how conservation patterns in gene expression mark important stages in the plant life cycle and potentially restrict evolutionary diversification.

Flower: A flower is the reproductive structure in flowering plants. It consists of sepals to protect the flower, petals to attract pollinators, and reproductive organs that produce gametophytes. Male gametophytes produce sperm in pollen grains, while female gametophytes are contained in ovules produced in the carpels.

Fruit: A fruit is a structure in flowering plants that develops from the ovary after flowering and contains seeds.

Berry (botany): A berry is a fleshy fruit from a single flower's ovary, without a stone. Common examples include grapes, tomatoes, and bananas. The outer layer of the ovary wall ripens into a potentially edible "pericarp". Berries can be formed from one or more carpels. Seeds are typically found in the fleshy interior, but some exceptions exist, like Capsicum species with air instead of pulp around their seeds.

Nut (fruit): A nut is a fruit with a hard or tough shell protecting an edible kernel. In culinary terms, many dry seeds are called nuts, but in a botanical sense, a nut refers to a shell that doesn't open to release the seed.

Leaf: A leaf is a plant appendage specialized for photosynthesis. It is part of the shoot system and collectively called foliage. Leaves usually have a flattened shape with distinct upper and lower surfaces. They contain chlorophyll, which gives them a green color and absorbs light energy for photosynthesis. Some leaves have palisade mesophyll on both sides, making them isobilateral. A leaf with lighter-colored or white patches is called a variegated leaf.

Root: Roots are plant organs that anchor and nourish the plant by absorbing water and nutrients, enabling plants to grow quickly and tall. They are usually found underground but can also grow above the ground or water.

Stoma: A stoma, or stomate, is a pore in plant tissues that controls gas exchange. It is bordered by guard cells that regulate the opening size.

Seed: A seed is a plant embryo and food reserve enclosed in a protective outer covering called a seed coat. It is the product of a fertilized ovule, and grows within the mother plant before growth is halted. The term "seed" can also refer to anything that can be sown, such as seed and husk or tuber.

Shrub: A shrub is a small-to-medium-sized perennial woody plant with persistent woody stems above the ground. They can be deciduous or evergreen and are shorter in height compared to trees, typically less than 6-10 m tall. Some smaller shrubs, less than 2 m tall, are known as subshrubs. Shrubs can be found in various botanical groups, and some have species that are trees or herbaceous plants instead.

Tree: A tree is a perennial plant with an elongated trunk that supports branches and leaves. It includes woody plants with secondary growth and those usable as lumber. Taller palm trees, tree ferns, bananas, and bamboos are also considered trees.

Plant stem: A plant stem is a primary structure of a vascular plant, along with the root. It provides support to leaves, flowers, and fruits, transports water and nutrients, enables photosynthesis, stores nutrients, and produces new tissue. It is also referred to as halm, haulm, or culms.

Bark (botany): Bark is the outermost layer of woody plants, including trees, vines, and shrubs. It consists of the tissues outside the vascular cambium and is composed of the inner and outer bark. The inner bark is alive and includes the innermost layer of the periderm, while the outer bark is dead and covers the stems' surface. The outer bark on trees, known as the rhytidome, lies outside the living periderm.

Trunk (botany): The trunk in botany refers to the main wooden axis of a tree. It is crucial for identifying tree species and varies in appearance from the bottom to the top.

Epidermis (botany): The epidermis in botany is a single layer of cells that covers the leaves, flowers, roots, and stems of plants. It acts as a protective barrier against water loss, facilitates gas exchange, secretes metabolic compounds, and absorbs water and nutrients. The upper and lower leaf surfaces have different constructions and functions. Some stems produce the periderm, a secondary covering that replaces the epidermis for additional protection.

Ground tissue: Ground tissue refers to plant tissues that are neither dermal nor vascular. It is divided into three types based on cell wall characteristics. Parenchyma cells have thin walls and remain alive after maturity, providing filler tissue. Collenchyma cells have thin walls with some thickened areas, offering mechanical support. Sclerenchyma cells have thick, lignified walls and provide the main structural support.

Meristem: Meristem is a plant tissue composed of undifferentiated cells that can divide. It has the potential to develop into various plant organs and tissues. Once cells in the meristem differentiate, they lose their ability to divide.

Vascular tissue: Vascular tissue is a conducting tissue in plants, composed of multiple cell types. It consists of xylem and phloem, which transport fluids and nutrients internally. The vascular tissue system includes two meristems: the vascular cambium and the cork cambium. It plays a crucial role in plant growth and maintenance.

Vascular cambium: The vascular cambium is the primary growth tissue found in the stems and roots of various plants. It produces secondary xylem towards the center and secondary phloem towards the outer surface.

Hypha: A hypha is a long, branching filamentous structure found in fungi, oomycetes, and actinobacteria. It serves as the primary mode of vegetative growth in most fungi, collectively forming a mycelium.

Mycelium: Mycelium is the root-like structure of a fungus made up of branching hyphae. It forms colonies on various substrates, including soil. When two compatible mycelia join, they form a dikaryotic mycelium which can give rise to fruiting bodies like mushrooms. Mycelium can range from microscopic to covering vast areas. It functions like a human brain by sending electrical signals to mushrooms, conveying information and alerting to potential threats.

Physiology: Physiology is the study of how living systems function and their mechanisms. It explores the chemical and physical processes carried out by organisms, organs, cells, and biomolecules. This field can be divided into medical, animal, plant, cell, and comparative physiology based on classes of organisms.

Circadian rhythm: A circadian rhythm is a natural 24-hour cycle that regulates biological processes in organisms. It is controlled by a circadian clock that coordinates these processes for optimal fitness. These rhythms exist in various life forms and evolved independently in animals, plants, fungi, and cyanobacteria.

Digestion: Digestion is the process of breaking down large food compounds into smaller, water-soluble components that can be absorbed into the bloodstream. It involves two main processes: mechanical digestion, which physically breaks down food, and chemical digestion, where enzymes break down food into usable compounds. Absorption of these smaller substances occurs primarily in the small intestine.

Excretion: Excretion is the elimination of metabolic waste from an organism. Vertebrates excrete waste mainly through the lungs, kidneys, and skin. Unlike secretion, excretion serves the purpose of eliminating waste rather than performing specific functions. It is vital for all forms of life. Mammals, for instance, expel urine through the excretory system, specifically the urethra. In unicellular organisms, waste products are discharged directly through the cell's surface.

Blood sugar level: Blood sugar level, also known as blood glucose level, is the amount of glucose present in the blood. It is tightly controlled by the body to maintain metabolic balance.

Metabolism: Metabolism is the set of chemical reactions in organisms that converts food into energy for cellular processes, builds proteins and other molecules, and eliminates waste. It allows organisms to grow, reproduce, and respond to their environment. This term can also encompass all the chemical reactions in living organisms, including digestion and transportation between cells.

Muscle contraction: Muscle contraction is the activation of tension-generating sites in muscle cells. It does not always cause muscle shortening, as tension can be produced without change in length. Muscle relaxation follows contraction, returning the muscle fibers to a low tension-generating state.

Photosynthesis: Photosynthesis is a process used by organisms to convert light energy into chemical energy stored in organic compounds. It produces oxygen and stores energy in carbohydrate molecules. Most plants, algae, and cyanobacteria perform photosynthesis and are called photoautotrophs. This process is responsible for maintaining Earth's oxygen levels and providing energy for complex life.

Respiration (physiology): Respiration is the process of exchanging oxygen and carbon dioxide between the environment and cells in tissues.

Thermoregulation: Thermoregulation is the ability of organisms to regulate their body temperature despite fluctuations in the surrounding temperature. It is a part of homeostasis, which is the body's effort to maintain internal stability. Hyperthermia occurs when the body temperature rises above normal, while hypothermia happens when the body temperature drops below normal. Wet-bulb temperature exceeding 30.55°C can cause heat stress. Thermometers have enabled the measurement of animal temperatures, revealing variations across different body parts. Typically, the rectum is considered the most accurate reflection of internal temperature.

Transpiration: Transpiration is the passive process in which plants move water through their structures and evaporate it from leaves, stems, and flowers. This process helps to cool plants, regulate osmotic pressure, and enable the flow of mineral nutrients. When plant roots absorb less water than is lost through evaporation, plants close tiny pores called stomata to reduce water loss. This, in turn, slows nutrient uptake, limits CO2 absorption, and hampers metabolic processes, photosynthesis, and growth.

Developmental biology: Developmental biology is the study of how animals and plants grow and develop. It includes the biology of regeneration, asexual reproduction, metamorphosis, and the growth and differentiation of stem cells in adults.

Development of the human body: The development of the human body is the process of growth from conception to adulthood. It begins with fertilization, followed by cell division and differentiation. The embryo implants in the uterus and goes through fetal development until birth. After birth, growth and development continue influenced by genetic, hormonal, environmental, and other factors, impacting both physical and psychological aspects throughout life.

Cuticle: A cuticle is a protective outer covering found in organisms, providing toughness and flexibility. It can be of different types, distinguished by their origin, structure, function, and chemical composition.

Embryo: An embryo is the earliest stage of a multicellular organism's development. It starts after the fusion of sperm and egg cells, forming a single-celled zygote. The zygote then undergoes multiple cell divisions creating blastomeres, forming a solid ball called a morula. The morula then develops a fluid-filled cavity known as a blastocoel, turning it into a blastula or blastocyst in mammals.

Fetus: A fetus is the developing offspring of an animal embryo. In humans, fetal development starts at around 9 weeks after fertilization and extends until birth. During this stage, all major body organs are present, but they are not yet fully developed or functional and may not be in their final position.

Imago: The imago is the final stage of an insect's metamorphosis, marking its maturity. This stage follows the last molting of immature instars. It is also referred to as the imaginal stage.

Larva: A larva is a juvenile form of many animals that undergoes metamorphosis into their next life stage. It is common in insects, amphibians, and cnidarians, with indirect development, during their life cycle.

Longevity: Longevity refers to exceptionally long-lived individuals in a population. It should not be confused with life expectancy, which is the statistical average number of remaining years at a certain age. For instance, a population's life expectancy at birth is the average age at death for all individuals born in a specific year.

Metamorphosis: Metamorphosis is a biological process involving a sudden and significant change in an animal's body structure through cell growth and differentiation. It occurs during birth, hatching, or transformation, and is observed in insects, fish, amphibians, mollusks, crustaceans, cnidarians, echinoderms, and tunicates. Metamorphosis is often accompanied by a change in nutrition source or behavior. Animals can undergo complete metamorphosis (holometaboly), incomplete metamorphosis (hemimetaboly), or no metamorphosis (ametaboly).

Moulting: Moulting, also called molting or shedding, is a biological process where an animal sheds parts of its body for a beneficial purpose. This can occur at specific times of the year or points in the animal's life cycle. In many invertebrates, moulting is known as ecdysis.

Nymph (biology): In biology, a nymph is an immature form of certain invertebrates, mainly insects, that gradually transforms into an adult through multiple stages called instars. Nymphs resemble adults but lack wings and do not go through a pupal stage. They moult until their final stage, where they become adult insects.

Ontogeny: Ontogeny is the process of an organism's origin and development from fertilization to adulthood. It can also refer to the study of an organism's entire lifespan.

Puberty: Puberty is the process by which a child's body transforms into an adult body capable of sexual reproduction. It is triggered by hormonal signals from the brain to the ovaries in females and testicles in males. Hormones produced by these organs stimulate growth, brain development, and the transformation of various body parts. This includes changes in the brain, bones, muscles, blood, skin, hair, breasts, and sex organs. As puberty progresses, there is a significant acceleration in physical growth, leading to the development of an adult body. Before puberty, primary sexual characteristics differentiate males and females, while puberty further brings about secondary sex characteristics that distinguish the sexes.

Pupa: A pupa is a life stage of some insects in which they transform from immature to mature stages. This stage is part of the four distinct stages in an insect's life cycle, namely egg, larva, pupa, and imago. Hormones play a crucial role in initiating and completing the pupal stage. The process of becoming a pupa is known as pupation, while the emergence from the pupal case is called eclosion or emergence.

Tadpole: A tadpole is the larval stage in an amphibian's life cycle. It is usually fully aquatic but can also be found on land. Tadpoles have fish-like features like gills, a lateral line, and swimming tails. During metamorphosis, they develop lungs and their diet shifts significantly.

Reproduction: Reproduction is the process of creating new organisms from existing ones. It can be either asexual or sexual.

Asexual reproduction: Asexual reproduction does not involve the fusion of gametes or change in chromosomes. Offspring inherit all genes from a single parent, making them genetically and physically similar or exact clones of the parent. It is the primary reproduction method for single-celled organisms and is common in plants, animals, and fungi. Parthenogenesis is a common form of asexual reproduction in vertebrates, used when reproductive opportunities are limited. Some reptiles, like Komodo dragons and monitor lizards, can reproduce asexually.

Sex: Sex is the trait that determines whether an organism produces male or female reproductive cells. Through sexual reproduction, these cells fuse to form an offspring that inherits traits from both parents. Organisms producing small, mobile gametes are called male, while those producing larger, non-mobile gametes are called female. Some organisms, like certain plants, can produce both types of gametes and are called hermaphrodites.

Sexual reproduction: Sexual reproduction combines two sets of chromosomes from gametes, resulting in a diploid zygote. Animals mainly use this method, but plants, fungi, and other eukaryotes show variations in chromosome sets during sexual reproduction.

Female: Summary: Females are organisms that produce the ovum, which is the gamete that merges with the male gamete during sexual reproduction.

Male: Male is the sex that produces sperm and requires the female ovum for sexual reproduction. While some organisms can reproduce both sexually and asexually, males generally have a Y chromosome that promotes the development of male reproductive organs and higher testosterone levels.

Microbial cyst: A microbial cyst is a dormant stage of a microorganism where metabolic processes slow down and all activities like feeding and movement cease. Many microbes can enter this state of suspended animation.

Spore: Spores are reproductive units in biology that can reproduce sexually or asexually. They are adapted for dispersal and survival in unfavorable conditions for extended periods of time. Spores are found in the life cycles of many plants, algae, fungi, and protozoa.

Egg: An egg is an organic vessel produced by animals for incubating and developing a fertilized egg cell into a self-sufficient animal fetus.

Birth: Birth, or parturition, is the act of giving birth to offspring. Hormones trigger contractions of the uterus, leading to the expulsion of the fetus, which can feed and breathe independently.

Semen: Semen, also known as seminal fluid, is an organic bodily fluid containing spermatozoa. It is produced in the seminal vesicle and released during ejaculation. Besides sperm, seminal fluid contains enzymes, fructose, and other components that aid in sperm survival and movement. Its purpose is to fertilize the female ovum by allowing sperm to travel through the vagina and into the uterus.

Sperm: Sperm is the male reproductive cell found in animals, red algae, fungi, and plants. It can be motile with a tail or non-motile. Animals produce motile sperm called spermatozoa, while red algae and fungi produce non-motile spermatia. Flowering plants have non-motile sperm inside pollen, and ferns and gymnosperms possess motile sperm.

Pregnancy: Pregnancy is when offspring develop inside a woman's uterus. It can involve multiple offspring, like twins.

Childbirth: Childbirth, or labor, is the process of delivering one or more babies from the mother's body either through vaginal delivery or caesarean section. It is estimated that around 140.11 million human births occurred worldwide in 2019. Developed countries predominantly rely on hospital deliveries, whereas home births are more common in developing countries.

Menstrual cycle: The menstrual cycle involves hormonal changes and uterine and ovarian activities, enabling pregnancy. The ovarian cycle regulates egg production, estrogen, and progesterone release. The uterine cycle prepares and maintains the uterus lining for implantation. These cycles typically last 21-35 days, with a median of 28 days, occurring for around 30-45 years.

Menopause: Menopause refers to the permanent cessation of menstrual periods, signaling the end of reproductive years, commonly occurring between the ages of 45 and 55. It can arise naturally or be induced by factors like smoking, certain surgeries, or chemotherapy. Menopause occurs due to a decline in estrogen and progesterone hormone production by the ovaries. Diagnosis can be confirmed through hormone level measurements. Menopause is opposite to menarche, which is the onset of a girl's periods.

Plant reproduction: Plant reproduction is the creation of new plants through sexual or asexual methods. Sexual reproduction involves combining gametes to generate genetically diverse offspring. Asexual reproduction leads to identical plants without gamete fusion unless mutations happen.

Alternation of generations: Alternation of generations is a common life cycle in plants and algae. It involves a multicellular haploid phase (gametophyte) and a multicellular diploid phase (sporophyte).

Gametophyte: A gametophyte is a multicellular organism that develops from a haploid spore and is one of the phases in the life cycles of plants and algae. It is the sexual phase that produces sex organs and gametes for fertilization. The fertilization results in a diploid zygote, which develops into a new multicellular organism called the sporophyte. This sporophyte can produce haploid spores that germinate into new gametophytes.

Plant reproductive morphology: Plant reproductive morphology studies the physical form and structure of plant parts involved in sexual reproduction. It explores the features related to plant reproduction.

Pollen: Pollen is a powdery substance produced by flowers for sexual reproduction. It contains male gametes protected by a hard coat. If it reaches a compatible pistil or female cone, it germinates and transfers sperm to the ovule. Studying pollen, called palynology, is useful in various fields. Pollen enables the transfer of genetic material between flowers for cross-pollination or within the same flower for self-pollination.

Pollination: Pollination is the process where pollen is transferred from a plant's anther (male part) to its stigma (female part), leading to fertilization and seed production. This is usually done by animals like insects, birds, and bats, as well as wind and water. Pollinating animals carry pollen between plants, crucial for genetic diversity in most flowering plants. Self-pollination happens within a single flower, while cross-species pollination can create hybrids in nature and plant breeding.

Sporophyte: A sporophyte is a diploid stage in the plant or alga life cycle that produces asexual spores. It alternates with a haploid gametophyte phase.

Biochemistry: Biochemistry is the study of chemical processes in living organisms, involving the fields of structural biology, enzymology, and metabolism. It explains living processes and contributes to understanding tissues, organs, and organism structure and function. It is closely connected to molecular biology and uses biochemical methods to uncover and develop all areas of life sciences.

Chemical biology: Chemical biology is an interdisciplinary field bridging chemistry and biology. It uses chemical techniques and small synthesized molecules to study and control biological systems. It is different from biochemistry as it applies chemical tools to understand biological phenomena.

Biomolecule: Biomolecules are essential molecules found in living organisms, playing crucial roles in various biological processes. They encompass large macromolecules like proteins, carbohydrates, lipids, and nucleic acids, as well as smaller molecules like vitamins and hormones. These biomolecules are necessary for cell division, development, and morphogenesis. While organisms produce their own biomolecules, they also require external sources of biomolecules, such as nutrients, to survive.

Alkaloid: Alkaloids are basic, naturally occurring organic compounds with at least one nitrogen atom. They can also have neutral or weakly acidic properties. Alkaloids may contain oxygen, sulfur, and sometimes elements like phosphorus, chlorine, and bromine. Some synthetic compounds can also be classified as alkaloids.

Caffeine: Caffeine is a stimulant that promotes wakefulness and enhances cognitive performance. It works by blocking adenosine receptors and increasing the release of acetylcholine. Additionally, it raises cyclic AMP levels through phosphodiesterase inhibition.

Cocaine: Cocaine is a stimulant that is widely used recreationally for its euphoric effects. It is obtained from South American Coca plants and can be administered through various methods such as snorting, topical application, and injection. Additionally, it has medicinal uses in Indigenous South American cultures and as a local anesthetic in developed countries. It can also be turned into a vapor for inhalation.

Morphine: Morphine is a powerful opiate derived from opium poppies. It is primarily used to relieve pain and can be administered through various methods. It acts directly on the central nervous system to alleviate pain and alter perception. Dependence and tolerance can develop with prolonged use. Morphine is commonly used for acute and chronic pain, including that caused by heart attacks, kidney stones, and childbirth. It reaches its maximum effect within 20 minutes when given by injection and within 60 minutes when taken orally. Long-acting forms of morphine are also available.

Nicotine: Nicotine is a natural alkaloid found in plants, commonly used as a stimulant and anxiety reliever. It is also used in pharmaceuticals to help people quit smoking by alleviating withdrawal symptoms. Nicotine acts as a receptor agonist in most nicotinic acetylcholine receptors but functions as a receptor antagonist in two specific receptor subunits.

Biological pigment: Biological pigments, also called pigments or biochromes, are produced by living organisms and create color through specific absorption. They encompass plant and flower pigments and are present in various structures like skin, eyes, feathers, and hair, residing in specialized cells called chromatophores. Some species accumulate pigments over extended periods of an individual's life.

Carotenoid: Carotenoids are organic pigments found in plants, algae, bacteria, archaea, and fungi, giving colors to various natural entities like pumpkins, carrots, corn, and daffodils. They can be classified as xanthophylls and carotenes, with over 1,100 identified variations.

Chlorophyll: Chlorophyll, derived from Greek words meaning "green leaf," is a green pigment found in cyanobacteria, algae, and plant chloroplasts. It enables plants to absorb light energy for photosynthesis.

Melanin: Melanin is a pigment found in organisms, made up of disordered oligomers or polymers. It is produced by melanocytes and provides pigmentation. Melanin is considered one of the last mysterious frontiers in biology.

Carbohydrate: Carbohydrates are biomolecules made up of carbon, hydrogen, and oxygen atoms, with an empirical formula of Cm(H2O)n. They have a hydrogen-oxygen atom ratio of 2:1. However, some carbohydrates may not strictly follow this stoichiometric definition, and not all chemicals that do are classified as carbohydrates.

Fructose: Fructose, also known as fruit sugar, is a ketonic simple sugar found in plants often combined with glucose to form sucrose. It is one of three monosaccharides absorbed into the bloodstream directly. In the liver, both fructose and galactose are converted into glucose, leaving glucose as the sole monosaccharide in circulating blood.

Glucose: Glucose is a highly prevalent sugar (C6H12O6) and the most abundant monosaccharide. It is primarily produced by plants and algae through photosynthesis, utilizing water, carbon dioxide, and sunlight. Glucose plays a crucial role in the formation of cellulose, the most abundant carbohydrate found in cell walls worldwide.

Lactose: Lactose is a disaccharide sugar found in milk, consisting of galactose and glucose subunits. It constitutes around 2-8% of milk by mass and is white, water-soluble, and non-hygroscopic. Lactose has a mildly sweet taste and is commonly used in the food industry.

Cellulose: Cellulose is a polysaccharide found in plants and algae, composed of D-glucose units. It forms the primary cell wall in green plants and some bacteria secrete it to make biofilms. Being the most common organic polymer on Earth, cellulose makes up 90% of cotton fiber, 40-50% of wood, and about 57% of dried hemp.

Chitin: Chitin is a durable polymer found in nature, second only to cellulose in abundance. It makes up cell walls in fungi, exoskeletons in arthropods, and various structures in molluscs, nematodes, and diatoms. It is also synthesized by certain fish and amphibians. Chitin is extracted from shellfish and crustacean shells, which are abundant in the seafood industry. Its structure is similar to cellulose and has similarities to the protein keratin. Chitin finds diverse applications in medicine, industry, and biotechnology.

Glycogen: Glycogen is a glucose-based energy storage molecule found in animals, fungi, and bacteria. In humans, it serves as the primary storage form of glucose in the body.

Starch: Starch is a polymeric carbohydrate made up of glucose units bonded together. It is produced by green plants as a way to store energy. It is the most common carbohydrate in human diets and can be found in staple foods like wheat, potatoes, corn, rice, and cassava.

Hormone: Hormones are signaling molecules that regulate physiology and behavior in multicellular organisms. They are crucial for the proper development of animals, plants, and fungi. Various molecules, including eicosanoids, steroids, amino acid derivatives, proteins or peptides, and gases, can be classified as hormones.

Adrenaline: Adrenaline, also known as epinephrine, is a hormone and medication involved in regulating bodily functions. It is produced by the adrenal glands and plays a crucial role in the fight-or-flight response. Adrenaline increases blood flow to muscles, heart output, pupil dilation, and blood sugar levels by binding to alpha and beta receptors. It is found in humans, animals, and some single-celled organisms. It has also been isolated from the Scoparia dulcis plant in Northern Vietnam.

Dopamine: Dopamine is a neuromodulatory molecule that functions as a neurotransmitter in the brain. It plays vital roles in the motivational component of reward-motivated behavior, as well as in motor control and hormone release. Dopamine is synthesized in the brain, kidneys, plants, and most animals. Its levels increase with anticipation of rewards and are impacted by addictive drugs. This neurotransmitter is part of a dopamine system that modulates various brain pathways and cell groups.

Estrogen: Estrogen is a sex hormone that plays a crucial role in the development and functioning of the female reproductive system and secondary sex characteristics. The three main types of estrogen are estrone, estradiol, and estriol, with estradiol being the most potent and abundant. Estetrol is an additional estrogen produced exclusively during pregnancy.

Insulin: Insulin is a peptide hormone produced by the pancreas that regulates the body's metabolism of carbohydrates, fats, and proteins. It promotes glucose absorption from the blood into various cells and regulates the synthesis of proteins. Insulin's high levels inhibit glucose production by the liver, while low levels promote catabolism and the breakdown of body fat.

Oxytocin: Oxytocin is a hormone and neuropeptide produced in the hypothalamus. It plays roles in behavior such as social bonding, reproduction, and childbirth. The hormone is released during sexual activity and labor, and is also available in pharmaceutical form. Oxytocin stimulates uterine contractions during childbirth and promotes maternal bonding and milk production. Its production is controlled by positive feedback, stimulating the release of more oxytocin. This hormone plays a similar role during lactation and sexual activity.

Testosterone: Testosterone is the primary male sex hormone responsible for the development of male reproductive organs and secondary sexual characteristics. It promotes muscle and bone growth, body hair, and affects behavior, mood, cognition, and metabolism. Insufficient testosterone levels in men may lead to various issues like frailty, weight gain, anxiety, sexual problems, and bone loss.

Plant hormone: Plant hormones are signal molecules produced in low concentrations within plants. They regulate plant growth, development, defense against pathogens, stress tolerance, and reproduction. Unlike animals, every plant cell can produce hormones. The term "phytohormone" was coined by Went and Thimann in 1937.

Lipid: Lipids are diverse organic compounds, including fats, waxes, and sterols. They serve as energy stores, cell membrane components, and signaling molecules. Lipids find applications in cosmetics, food, and nanotechnology.

Fat: Fat refers to esters of fatty acids or a combination of these compounds found in living organisms and food.

Fatty acid: A fatty acid is a type of carboxylic acid with a long, straight chain of carbon atoms. It can be either saturated or unsaturated. Most fatty acids found in nature have an unbranched chain with an even number of carbon atoms ranging from 4 to 28. While some organisms have fatty acids in their pure form, others have them as esters, specifically triglycerides, phospholipids, or cholesteryl esters. Fatty acids serve as a vital energy source for animals and play essential roles in cell structure.

Nucleic acid: Nucleic acids are essential biomolecules found in all cells and viruses. They consist of nucleotides, which have three components: a 5-carbon sugar, a phosphate group, and a nitrogenous base. There are two main types of nucleic acids: DNA and RNA. DNA is made up of deoxyribose sugar, while RNA contains ribose sugar.

DNA: DNA is a double helix polymer that carries genetic instructions for organisms and viruses. It is one of the four major macromolecules crucial for all life, along with proteins, lipids, and carbohydrates.

RNA: RNA is a vital molecule involved in various biological functions. It serves as a template for protein production and is crucial for all forms of life. It consists of nucleotides linked together, and messenger RNA conveys genetic information for protein synthesis. Additionally, some viruses utilize RNA as their genetic material.

Protein: Proteins are large biomolecules made up of amino acids. They have diverse functions, including catalyzing reactions, replicating DNA, responding to stimuli, providing structure, and transporting molecules. Each protein has a unique sequence of amino acids determined by its genes, and this sequence shapes its 3D structure and activity.

Amino acid: Amino acids are organic compounds with amino and carboxylic acid groups. There are over 500 types, but only 22 are essential for protein synthesis as they appear in the genetic code.

Enzyme: Enzymes are proteins that accelerate chemical reactions in living organisms. They convert substrates into different products, playing a crucial role in metabolic processes and sustaining life. Enzymes catalyze individual steps in metabolic pathways. Enzymology is the study of enzymes, which can also reveal pseudocatalytic properties of some enzymes that have lost their biological catalysis ability over evolution.

Hemoglobin: Hemoglobin is an iron-containing protein found in red blood cells that transports oxygen. It is present in almost all vertebrates except for certain fish and invertebrates. It carries oxygen from the respiratory organs to body tissues, enabling aerobic respiration and powering metabolism. A healthy human has 12 to 20 grams of hemoglobin in every 100 mL of blood. Hemoglobin is a metalloprotein, chromoprotein, and globulin.

Protein (nutrient): Proteins are vital nutrients for the body, serving as building blocks for tissue and a source of fuel. They provide the same energy density as carbohydrates but less than lipids. The amino acid composition is the key nutritional aspect of proteins.

Steroid: A steroid is a type of organic compound consisting of four fused rings arranged in a specific molecular structure.

Cholesterol: Cholesterol is a vital sterol found in the tissues of animals, particularly in the brain, spinal cord, and animal fats.

Molecular biology: Molecular biology is a field of biology studying the molecular foundation of biological processes within and between cells. It investigates vital aspects such as biomolecule synthesis, modification, mechanisms, and interactions.

Gene expression: Gene expression is the process where genetic information is used to create functional gene products, like proteins or non-coding RNA, which affects an organism's traits. It follows the central dogma of molecular biology and involves transcription, translation, and replication.

Genetic code: The genetic code is a set of rules that living cells use to convert genetic information into proteins. This process is carried out by the ribosome, which uses RNA molecules to assemble amino acids in a specific order based on the messenger RNA. The code is shared across organisms and can be represented in a table with 64 entries.

DNA replication: DNA replication is the biological process of making two identical copies of DNA from one original molecule. It is crucial for cell division, tissue repair, and genetic inheritance.

Transcription (biology): Transcription (biology) is the copying of DNA into RNA. DNA segments transcribed into mRNA encode proteins, while other segments produce non-coding RNAs.

Translation (biology): Translation in biology is the process of creating proteins using RNA molecules as templates. Amino acid sequences are determined by RNA nucleotide sequences, with each group of three nucleotides corresponding to a specific amino acid. This process is guided by the genetic code and carried out by ribosomes. Overall, translation is a vital part of gene expression in living cells.

Zoology: Zoology, derived from Ancient Greek, is the scientific study of animals. It encompasses the examination of animal structure, embryology, classification, habits, and distribution, including both living and extinct species. Zoology explores animal interactions within their ecosystems and is a significant branch of biology.

Animal: Animals are multicellular organisms in the Animalia kingdom. They breathe oxygen, consume organic material, have myocytes for movement, reproduce sexually, and develop from a blastula during embryonic growth.

Animal coloration: Animal coloration refers to the appearance of an animal caused by light reflection or emission. It varies greatly, with some animals being brightly colored and others being camouflaged. Certain species, like peafowls, have males with striking patterns, vibrant colors, and iridescence, while females are less noticeable.

Camouflage: Camouflage is the use of materials, coloration, or illumination to hide animals or objects by either making them hard to see or disguising them as something else. It includes methods like cryptic resemblance, disruptive coloration, and motion dazzle. Camouflage can also involve transparency, silvering, and countershading in the open ocean. Some animals can actively change their skin pattern and colors for camouflage or signaling. Plants may also use camouflage to avoid being eaten by herbivores.

Ethology: Ethology is a branch of zoology that scientifically studies non-human animal behavior in their natural environment, emphasizing its evolutionary adaptiveness. It originated from the work of naturalists and has evolved into a modern discipline through the contributions of influential scientists like Darwin, Tinbergen, Lorenz, and von Frisch. Ethology combines laboratory and field research, with connections to neuroanatomy, ecology, and evolutionary biology. Ethologists focus on behavioral processes rather than specific animal groups, often examining a particular behavior, such as aggression, across multiple species.

Intelligence: Intelligence is the multifaceted ability to understand, learn, reason, solve problems, and apply knowledge creatively. It involves perceiving and retaining information for adaptive behavior within a given context.

Sleep: Sleep is a altered state of reduced activity where consciousness and sensory activity are hindered. It involves decreased muscle activity and interaction with the environment. While less responsive than wakefulness, sleep still exhibits active brain patterns, setting it apart from coma or disorders of consciousness.

Hibernation: Hibernation is a seasonal state of minimal activity and reduced metabolism that some animals undergo, characterized by low body temperature, slow breathing and heart rate, and decreased metabolic rate. It primarily occurs during winter months.

Carnivore: A carnivore is an organism that obtains its energy by consuming animal tissues, obtained through hunting or scavenging.

Predation: Predation is the act of one organism killing and consuming another, known as prey. It falls under a category of feeding behaviors that includes parasitism and parasitoidism. Predation differs from scavenging and can overlap with herbivory when predators consume plant seeds or destroy fruits.

Scavenger: Scavengers are animals that feed on dead organisms not killed by predation. They consume carrion and also plant material. They play a vital role in the ecosystem by removing dead animal and plant material. Decomposers and detritivores consume the remains after scavengers have finished.

Herbivore: A herbivore is an animal adapted to eating plant material as its main diet. Their mouthparts are usually adapted for rasping or grinding. Examples include horses, which have wide flat teeth for grinding tough plant material.

Grazing: Grazing is an agricultural practice where livestock are allowed to freely roam and eat wild vegetation. This method helps animals convert cellulose from grass and forage into valuable products like meat, milk, and wool. Grazing is typically done on land that is unsuitable for crop farming.

Animal locomotion: Animal locomotion refers to the ways animals move. They use various self-propelled methods like running, swimming, jumping, flying, hopping, soaring, and gliding. Some animals rely on their surroundings for transportation, using passive methods like sailing, kiting, rolling, or riding other animals.

Bipedalism: Bipedalism is the movement of an animal or machine using its two rear limbs or legs. It includes walking, running, and hopping. Animals or machines that move this way are called bipeds, meaning 'two feet'.

Animal migration: Animal migration refers to the seasonal movement of animals over long distances. It is a widespread phenomenon among various animal groups such as birds, mammals, fish, reptiles, amphibians, insects, and crustaceans. Migration is triggered by factors like climate, food availability, mating, and occurs regularly in ecology.

Instinct: Instinct is a natural inclination of living organisms towards specific complex behaviors. It involves innate elements and is characterized by fixed action patterns (FAPs) where a defined stimulus triggers a sequence of unvarying actions.

Sociality: Sociality refers to the level at which animals within a population form social groups and cooperative societies.

Botany: Botany, also known as plant science, is the scientific study of plant life and is a branch of biology. It involves the examination of various plant species by experts called botanists or plant scientists. The term "botany" comes from an Ancient Greek word meaning pasture, herbs, grass, or fodder, which is derived from a word meaning to feed or graze. While traditionally including fungi and algae, botany now mainly focuses on around 410,000 species of land plants, including vascular plants and bryophytes.

Plant: Plants are eukaryotes in the kingdom Plantae, primarily photosynthetic. They derive energy from sunlight using chloroplasts and chlorophyll. However, parasitic plants lack chlorophyll and photosynthesis genes, obtaining energy from other plants or fungi.

Carnivorous plant: Carnivorous plants obtain nutrients by trapping and consuming animals and protozoans, mainly insects and arthropods. They still rely on photosynthesis for energy. These plants thrive in nutrient-poor environments such as acidic bogs and places with thin soil. They can be found on all continents except Antarctica and numerous Pacific islands. Charles Darwin's book in 1875, titled Insectivorous Plants, was the first to highlight the importance of carnivory in plants after thorough study and research.

Flowering plant: Flowering plants, or angiosperms, are the most diverse group of land plants. They bear flowers and fruits, and their seeds are enclosed within a fruit. This group includes grasses, trees, shrubs, vines, and most aquatic plants. With approximately 300,000 known species, they have 64 orders, 416 families, and 13,000 known genera.

Eudicots: Eudicots, also known as Eudicotidae or eudicotyledons, are a group of flowering plants. They are distinctive for having two seed leaves when they first sprout. The name is derived from the term Dicotyledons.

Magnoliids: Magnoliids are a large group of flowering plants, consisting of over 10,000 species. They include well-known plants like magnolias, nutmeg, and avocado. Magnoliids are the third-largest group of angiosperms after eudicots and monocots. They have trimerous flowers, pollen with one pore, and typically have branching-veined leaves.

Monocotyledon: Monocotyledons, also known as monocots, are angiosperms characterized by grass and grass-like flowering plants. Their seeds typically have only one embryonic leaf, or cotyledon. Monocots form a major group within flowering plants, while those with two cotyledons are classified as dicots.

Weed: A weed is an undesirable plant that grows where it conflicts with human preferences, needs, or goals. Weeds have characteristics that make them hazardous, aesthetically unappealing, or difficult to control in managed environments. They are unwanted in various areas including farm land, gardens, and parks. In agriculture, weeds can cause major losses in crop yields. Invasive species may also be considered weeds as they negatively impact ecosystem functioning and biodiversity.

Cell biology: Cell biology is the study of cells, which are the basic building blocks of all living organisms. It investigates the structure, function, and behavior of cells, including their metabolism, communication, and composition. Various techniques like microscopy, cell culture, and cell fractionation are used to understand cell functioning. Research in cell biology has implications for understanding larger organisms and has connections to fields like genetics, molecular biology, immunology, and medical microbiology. It is crucial for biomedical research and provides insights into diseases like cancer.

Programmed cell death: Programmed cell death, also known as PCD, refers to the death of a cell due to internal events like apoptosis or autophagy. It is a biological process that provides advantages in an organism's lifecycle. An example is the separation of fingers and toes in a human embryo, where cells between the fingers undergo apoptosis. PCD plays crucial roles in the development of both plant and animal tissues.

Cell signaling: Cell signaling is an essential biological process where cells communicate with each other, their own components, and their surroundings. It is a crucial aspect of cellular life found in both prokaryotes and eukaryotes.

Stem cell: Stem cells are versatile cells that can develop into different cell types and replicate indefinitely. Found in both embryonic and adult organisms, they exhibit distinct properties. Differing from progenitor and precursor cells, they are the earliest cells in a cell lineage, capable of unlimited division.

Cellular respiration: Cellular respiration is the metabolic process in cells that converts nutrients into ATP and releases waste products. It involves oxidizing biological fuels in the presence of an inorganic electron acceptor, such as oxygen, to produce energy-rich ATP molecules.

Glycolysis: Glycolysis is a metabolic pathway that converts glucose into pyruvate, producing energy in the form of ATP and NADH. It occurs within the liquid part of cells and involves ten enzyme-catalyzed reactions.

Fermentation: Fermentation is a metabolic process that uses enzymes to chemically transform organic substances. It can extract energy from carbohydrates without oxygen and can also improve the quality of food and beverages through the activity of microorganisms. The science behind fermentation is called zymology.

Active transport: Active transport is the movement of molecules or ions across a cell membrane against their concentration gradient, requiring cellular energy. It can be classified into primary active transport (using ATP) and secondary active transport (using an electrochemical gradient). This process differs from passive transport, as it involves energy expenditure for the movement of molecules or ions across the membrane.

Cell cycle: The cell cycle is a series of events in a cell that leads to its division into two daughter cells. These events involve DNA and organelle duplication, as well as the separation of cytoplasm, chromosomes, and other components during cell division.

Fission (biology): Fission in biology refers to the division of a single entity into two or more parts, which then regenerate into separate entities resembling the original. It can occur in cells, organisms, bodies, populations, or species. There are two types of fission: binary fission, where one organism produces two parts, and multiple fission, where one entity produces multiple parts.

Meiosis: Meiosis is a special type of cell division that produces gametes in sexually-reproducing organisms. It involves two rounds of division, resulting in four haploid cells with one copy of each chromosome. Meiosis also involves genetic crossover, creating new combinations of code on each chromosome. During fertilization, the haploid cells fuse to create a zygote with two copies of each chromosome again.

Mitosis: Mitosis is a cell division process in which replicated chromosomes are separated into two new nuclei. It is an equational division resulting in genetically identical cells with the same number of chromosomes. It occurs after the S phase of interphase and is followed by telophase and cytokinesis. The stages of mitosis define the division of the mother cell into two genetically identical daughter cells.

Plasmid: A plasmid is a small DNA molecule found outside the main chromosome in cells. It can replicate independently and is commonly seen in bacteria, but also in archaea and eukaryotes. Plasmids often carry genes that assist an organism's survival and provide resistance to antibiotics. Unlike chromosomes, plasmids are small and contain additional genes for specific situations. In molecular cloning, artificial plasmids are used as vectors to replicate recombinant DNA sequences. Plasmids can be introduced into cells for further study. Synthetic plasmids can be easily procured online.

Cell (biology): A cell is the fundamental unit of life, comprising of cytoplasm enclosed within a membrane. It contains macromolecules like proteins, DNA, RNA, and various small molecules. The term originates from the Latin word cellula meaning 'small room'.

Cell membrane: The cell membrane is a protective barrier in cells, made of a lipid bilayer with proteins and cholesterol. It controls what enters and leaves the cell and facilitates cellular processes such as adhesion and signaling. It also serves as the attachment surface for extracellular structures and can be artificially created in synthetic biology.

Cytoplasm: The cytoplasm is the material within a cell, excluding the nucleus. It consists of cytosol, organelles, and inclusions. It is predominantly water and lacks color.

Cytoskeleton: The cytoskeleton is a dynamic network of protein filaments found in all cells. It includes microfilaments, intermediate filaments, and microtubules, and extends from the nucleus to the cell membrane. This complex structure allows for rapid growth or disassembly, adapting to the cell's needs.

Flagellum: A flagellum is a hairlike structure found in plant and animal sperm, fungal spores, and various microorganisms, used for movement. It enables motility in many protists, which are called flagellates.

Symbiogenesis: Symbiogenesis is an evolutionary theory explaining how eukaryotic cells evolved from prokaryotes. It suggests that mitochondria and chloroplasts in eukaryotic cells originated from once independent prokaryotes that were engulfed by other cells in a process called endosymbiosis. Mitochondria are likely related to Rickettsiales bacteria, while chloroplasts are believed to have descended from cyanobacteria.

Organelle: Organelles are specialized subunits within cells that perform specific functions. The term organelle is derived from the idea that these structures are like organs in the body. They can either have their own lipid bilayers or be spatially distinct functional units. While most organelles are found within cells, some extend outside of cells and are still considered organelles, such as cilia, flagellum, archaellum, and trichocyst.

Cell nucleus: The cell nucleus is a membrane-bound organelle in eukaryotic cells. It usually consists of a single nucleus, but some cell types lack a nucleus. The nucleus is composed of the nuclear envelope, which encloses the organelle, and the nuclear matrix, which provides mechanical support.

Chromosome: A chromosome is a DNA package containing an organism's genetic material. It consists of long DNA fibers coated with nucleosome-forming proteins called histones. These proteins, along with chaperones, condense and preserve the DNA's integrity. Chromosomes also have a complex three-dimensional structure that plays a vital role in gene activation and regulation.

Centriole: A centriole is a cylindrical organelle made of tubulin protein. It is found in most eukaryotic cells but not in certain plant groups. Centrioles form a centrosome when paired and surrounded by dense material called pericentriolar material (PCM).

Endoplasmic reticulum: The endoplasmic reticulum (ER) is the transportation system and a crucial organelle in eukaryotic cells. It consists of the rough ER (RER), involved in protein folding, and the smooth ER (SER). These interconnected membranes form flattened sacs called cisternae and tubular structures. ER membranes are connected to the outer nuclear membrane but are absent in red blood cells and spermatozoa.

Golgi apparatus: The Golgi apparatus, also known as Golgi complex or Golgi body, is an organelle found in eukaryotic cells. It packages proteins into vesicles before sending them to their destination. It plays a crucial role in processing proteins for secretion, utilizing glycosylation enzymes to attach sugars. The Golgi apparatus is located at the intersection of secretory, lysosomal, and endocytic pathways within the cell.

Lysosome: A lysosome is a membrane-bound organelle in animal cells that contains enzymes for breaking down various biomolecules. It has a specific composition of proteins in its membrane and lumen. Operating at an acidic pH, lysosomes resemble the stomach's activity and are involved in degradation, cell processes like secretion and apoptosis, as well as energy metabolism.

Mitochondrion: A mitochondrion is a double-membrane organelle found in most eukaryotes that generates ATP through aerobic respiration, providing chemical energy to the cell. It was discovered in 1857 and is known as the "powerhouse of the cell".

Ribosome: Ribosomes are cellular machines that synthesize proteins by linking amino acids according to messenger RNA codons. They are composed of small and large subunits, consisting of ribosomal RNA molecules and proteins. These macromolecular structures, also known as the translational apparatus, are present in all cells.

Vacuole: A vacuole is a membrane-bound organelle found in plant, fungal, protist, animal, and bacterial cells. It is a compartment filled with water containing various molecules, including enzymes. Vacuoles can also contain solid material. They are formed by the fusion of membrane vesicles and their size and shape vary according to cell needs.

Plant cell: Plant cells are the cells found in green plants. They have primary cell walls with cellulose, hemicelluloses, and pectin. These cells contain plastids that perform photosynthesis and store starch. They have a large vacuole that regulates turgor pressure. Flagella and centrioles are absent, except in gametes. Plant cells divide using a unique method involving a cell plate or phragmoplast.

Cell wall: A cell wall is a structural layer outside the cell membrane, providing support, shape, protection, and acting as a selective barrier. It helps cells withstand osmotic pressure and mechanical stress. Cell walls are common in fungi, algae, plants, and most prokaryotes except mollicute bacteria.

Chloroplast: A chloroplast is a plastid organelle found in plant cells that conducts photosynthesis. Chlorophyll captures sunlight energy and converts it into ATP and NADPH, while releasing oxygen from water. These energy molecules are then used in the Calvin cycle to create organic compounds. Chloroplasts also have other functions like fatty acid and amino acid synthesis, as well as participating in the immune response. The number of chloroplasts per cell varies from one in unicellular algae to up to 100 in plants like Arabidopsis and wheat.

Plastid: Plastids are membrane-bound organelles found in plant, algae, and other eukaryotic cells. They are believed to have originated from endosymbiotic cyanobacteria and include chloroplasts, chromoplasts, and leucoplasts.

Ecology: Ecology is the study of living organisms and their relationship with the environment. It explores individuals, populations, communities, ecosystems, and the biosphere. Ecology is closely related to biogeography, evolutionary biology, genetics, ethology, and natural history.

Biome: A biome is a biological community shaped by the environment and regional climate, which can span across multiple continents. It encompasses various habitats, making it broader than the term "habitat".

Biodiversity: Biodiversity refers to the variety and variability of life on Earth, encompassing genetic, species, and ecosystem diversity. It is not evenly distributed, with higher levels found in the tropics and marine ecosystems along coasts in the Western Pacific. Biodiversity tends to cluster in hotspots and has been increasing historically, but deforestation poses a threat to its future. It encompasses the processes that sustain life, including evolution, ecology, and culture.

Competition (biology): Competition in biology refers to the interaction between organisms or species that compete for limited resources. It reduces the fitness of both organisms as one's presence diminishes the available resources for the other.

Symbiosis: Symbiosis is a close and long-term interaction between two different species, where they live together. It can be mutualistic (beneficial for both), commensalistic (beneficial for one, neutral for the other), or parasitic (beneficial for one, harmful for the other). The term was coined by Heinrich Anton de Bary in 1879, describing the living together of unlike organisms. It can also refer specifically to interactions where both symbionts contribute to each other's support.

Parasitism: Parasitism is a relationship where one species, the parasite, lives on or inside another organism, the host, causing harm. The parasite is structurally adapted to this lifestyle. Examples include protozoans causing malaria and dysentery, animals like lice and mosquitoes, fungi like ringworm, and plants like mistletoe and dodder.

Biosphere: The biosphere, or ecosphere, encompasses all ecosystems on Earth. It is the zone of life and integrates all living beings and their interactions with the lithosphere, cryosphere, hydrosphere, and atmosphere. The biosphere is a closed system for matter but open for energy, with photosynthesis capturing solar energy. It is believed to have emerged around 3.5 billion years ago through biopoiesis or biogenesis.

Ecological niche: An ecological niche refers to how a species adapts to its environment, including the resources available and competition with other species. It also describes how the species influences the environment in return. The specific factors involved can vary between species and contexts.

Ecosystem: An ecosystem is a system where environments and organisms interact. Biotic and abiotic components are connected through nutrient cycles and energy flows.

Endangered species: An endangered species is a species at high risk of extinction due to factors like habitat loss, poaching, and invasive species. The International Union for Conservation of Nature (IUCN) Red List tracks the conservation status globally, while other agencies assess species within specific regions. Many nations have laws protecting these species, prohibiting hunting and promoting conservation measures. Conservation efforts include captive breeding and habitat restoration.

Extinction: Extinction refers to the complete extinction of a group of organisms when its last member dies. In some cases, a group may become functionally extinct if it loses the ability to reproduce and recover. Determining the exact moment of extinction is challenging and often done retrospectively. This difficulty has led to instances like Lazarus taxa, where a species reappears unexpectedly after being presumed extinct.

Extremophile: An extremophile is an organism that thrives in extreme environments with conditions that challenge the limits of known life, including extreme temperature, radiation, salinity, or pH level.

Habitat: Habitat is the specific environment that provides the necessary resources for a particular species to survive and reproduce. It includes physical and biological factors within an area and can be considered the physical representation of a species' ecological niche. The term "habitat" differs from concepts like environment or vegetation assemblages, with "habitat-type" being more suitable for these broader concepts.

Invasive species: An invasive species is introduced to a new environment and becomes overpopulated, causing harm. It affects habitats and regions, leading to ecological, environmental, and economic damage. This term can also refer to native species that become harmful due to human-induced changes in their food web. Since the 20th century, invasive species have become a global threat, posing significant economic, social, and environmental challenges.

Population: The term 'Population' typically refers to the number of people in an area. Governments conduct censuses to measure the size of a resident population. It is also used to describe non-human organisms and has applications in fields like ecology and genetics.

Sustainability: Sustainability is a social goal aiming for long-term co-existence on Earth. It consists of three dimensions - environmental, economic, and social - with emphasis on countering major environmental issues. It guides decisions at various levels and is often used interchangeably with sustainable development, which emphasizes the processes to achieve sustainability. UNESCO differentiates the terms by associating sustainability with a long-term goal and sustainable development with the pathways to attain it.

Wildlife conservation: Wildlife conservation involves protecting wild species and their habitats to maintain healthy populations and restore ecosystems. Threats to wildlife include habitat destruction, overexploitation, poaching, pollution, climate change, and illegal trade. Thousands of species are at risk, with estimates ranging from 42,100 to a million. Ecosystems with endangered species are disappearing. National and international efforts, including conservation agreements like CITES and CBD, aim to preserve Earth's wildlife. NGOs like the Nature Conservancy and World Wildlife Fund also play a crucial role in conservation.

Genetics: Genetics is the study of genes, genetic variation, and heredity in organisms. It explores how traits are inherited and passed down from parents to offspring. Gregor Mendel, a 19th-century friar, was the first to scientifically study genetics. He discovered that traits are inherited through discrete units called genes, which remain a fundamental concept in genetics today.

Gene: In biology, a gene is both a basic unit of heredity and a sequence of nucleotides in DNA. Genes can be categorized into two types: protein-coding genes and non-coding genes.

Heredity: Heredity refers to the transfer of traits from parents to offspring through asexual or sexual reproduction, whereby offspring acquire genetic information from their parents. This process leads to genetic variations that can accumulate and drive species evolution through natural selection. The field of genetics studies heredity in biology.

Mendelian inheritance: Mendelian inheritance refers to the principles of biological inheritance proposed by Gregor Mendel and later rediscovered and popularized by other scientists. These principles initially faced controversy but were later integrated with the chromosome theory of inheritance and became the foundation of classical genetics. The combination of Mendelian inheritance and natural selection formed the basis for population genetics and the modern evolutionary synthesis.

Mutation: A mutation is a change in the DNA sequence of an organism's genome, viral genome, or extrachromosomal DNA. These changes can occur during replication or as a result of damage to DNA. Mutations can also be caused by the insertion or deletion of DNA segments due to mobile genetic elements.

Human genome: The human genome refers to the complete set of DNA sequences found in humans. It is composed of DNA in the chromosomes and mitochondria. The genome includes coding and non-coding DNA, which can encode proteins or have various other functions. Non-coding DNA consists of diverse elements such as regulatory sequences, structural regions, repetitive sequences, and non-functional pseudogenes. However, there is no consensus on the exact amount of non-functional junk DNA.

Epigenetics: Epigenetics is the study of heritable traits that occur without changes to DNA, involving changes in cell function. It encompasses features beyond traditional genetic mechanisms, affecting gene expression regulation. These changes persist through cell division and can be influenced by environmental factors or normal development. Epigenetic alterations have been linked to the development of cancer.

Hybrid (biology): A hybrid is the offspring of two organisms from different varieties, species, or genera through sexual reproduction. It contains genetic material from both parents and can exhibit hybrid vigor, growing larger than either parent. Hybrids are not always intermediate between parents. In animal and plant breeding, individual parentage is important, while in genetics, chromosome numbers are a focus. In taxonomy, the degree of relatedness between parent species is a crucial aspect.

Natural selection: Natural selection is the process by which individuals with favorable traits are more likely to survive and reproduce, resulting in the genetic characteristics of a population changing over time. It is a fundamental part of evolution and was first introduced by Charles Darwin. Unlike artificial selection, natural selection occurs without intentional human intervention.

Genetic drift: Genetic drift, or random genetic drift, refers to the random changes in the frequency of a gene variant in a population. This is caused by chance and can be described as the Wright effect.

Adaptation: Adaptation in biology refers to the process of natural selection that helps organisms fit into their environment, improving their evolutionary fitness. It is also a state achieved by a population during this process. Additionally, adaptation encompasses phenotypic traits in individual organisms that have evolved and are maintained through natural selection.

Human evolution: Human evolution is the process that led to Homo sapiens, a distinct species within the hominid family. It involved the development of traits like bipedalism, dexterity, and complex language. Human evolution was not linear but involved interbreeding with other hominins. The study of human origins, called anthropogeny, involves disciplines like physical anthropology, evolutionary anthropology, paleontology, and genetics.

Australopithecus: Australopithecus is a genus of early hominins that lived in Africa during the Pliocene and Early Pleistocene. It is an important member of the Australopithecina subtribe, which may also include Ardipithecus. Species within Australopithecus include A. garhi, A. africanus, A. sediba, and A. afarensis. It is debated whether some Australopithecus species should be classified under different genera. Homo, Paranthropus, and Kenyanthropus are believed to have evolved from certain Australopithecus species.

Paranthropus: Paranthropus, an extinct hominin genus, comprises two accepted species - P. robustus and P. boisei. The validity of Paranthropus is debated, and it is sometimes considered synonymous with Australopithecus. These robust australopithecines lived around 2.9 to 1.2 million years ago, spanning the end of the Pliocene to the Middle Pleistocene.

Homo habilis: Homo habilis, an extinct archaic human species, lived in East and South Africa from about 2.31 million years ago to 1.65 million years ago. Initially controversial, it gained recognition as a distinct species over time. It was proposed to be a human ancestor, evolving into Homo erectus and eventually modern humans. Some specimens were later divided into "H. rudolfensis" and "H. gautengensis", with the former receiving more support.

Homo erectus: Homo erectus was an ancient human species that lived during the Pleistocene, about 2 million years ago. They are considered early members of the Homo genus.

Denisovan: Denisovans (di-NEE-sə-və) were an extinct archaic human species in Asia during Paleolithic times. Limited physical remains exist, so most knowledge comes from DNA evidence. More complete fossil material is needed to establish a formal species name.

Neanderthal: Neanderthals, or cavemen, were an extinct species of archaic humans living in Eurasia until 40,000 years ago. Neanderthal 1, the type specimen, was discovered in Germany's Neander Valley in 1856.

Cro-Magnon: Cro-Magnons were the first early modern humans in Europe, arriving around 56,800 years ago. They interbred with Neanderthals but left no genetic legacy in modern Europeans. A second wave of modern humans formed a single founder population around 37,000 years ago, contributing ancestry to present-day Europeans. They developed Upper Palaeolithic cultures, including the Aurignacian and Gravettian. The Last Glacial Maximum caused climatic changes, leading to the split of the Gravettian into the Epi-Gravettian and Solutrean. As Europe warmed, the Magdalenian culture emerged around 20,000 years ago, eventually being replaced by Mesolithic cultures.

Arthropod: Arthropods are invertebrates with an exoskeleton made of chitin. They have a segmented body and jointed appendages. The process of moulting allows them to grow. With over 10 million species, they are a highly diverse group.

Bilateria: Bilateria is a major group of animals known as bilaterians, recognized by their bilateral symmetry during embryonic development. They have a body plan centered around a longitudinal axis with front and rear ends, as well as a symmetrical belly and back. While most bilaterians maintain this symmetry as adults, echinoderms are an exception, developing pentaradial symmetry. Cephalization, where sense organs and nerve ganglia concentrate in the front of the body, is a prominent feature among bilaterians.

Chordate: A chordate is a type of animal belonging to the phylum Chordata. It is characterized by five unique physical traits: a notochord, a hollow dorsal nerve cord, an endostyle or thyroid, pharyngeal slits, and a post-anal tail. The name "chordate" comes from the notochord, which plays a crucial role in their body plan and movements. Chordates are bilaterally symmetric, have a coelom, a closed circulatory system, and exhibit metameric segmentation.

Craniate: A craniate is a chordate animal with a hard bone or cartilage skull. Living craniates include hagfish, hyperoartia, and gnathostomata. Previously excluding hagfish, recent research has now considered them as vertebrates, making craniates synonymous with vertebrates.

Gnathostomata: Gnathostomata refers to jawed vertebrates and comprises around 60,000 species, representing 99% of all living vertebrates, including humans. These animals possess opposing jaws, true teeth, and paired appendages. They also have distinct physiological and cellular traits such as myelin sheaths in neurons and an adaptive immune system with discrete lymphoid organs. The inner ear of gnathostomes contains a horizontal semicircular canal, and their antigen recognition sites are generated through V(D)J recombination.

Invertebrate: Invertebrates are animals without a backbone. They do not have a vertebral column, which evolved from the notochord. Invertebrates include a wide range of animals, such as arthropods, mollusks, annelids, echinoderms, flatworms, cnidarians, and sponges. They form a paraphyletic group, excluding vertebrates.

Tetrapod: A tetrapod refers to any four-limbed vertebrate animal. This superclass includes both living and extinct amphibians and amniotes. Amniotes have evolved into two major groups: sauropsids and synapsids. Some tetrapods, like snakes and caecilians, have lost their limbs due to mutations in the Hox gene, but may still retain remnant hindlimbs.

Vertebrate: Vertebrates are animals with a backbone made of bones or cartilage. This includes fish, amphibians, reptiles, birds, and mammals. They are part of the subphylum Vertebrata and make up the majority of the phylum Chordata, with approximately 69,963 known species.

Domestic short-haired cat: Domestic short-haired cats are cats with short fur that do not belong to any recognized breed. They are commonly known as moggies in the United Kingdom. Unlike specific breeds, they are not registered with cat breed registries. Domestic short-haired cats are the most common type of cat in the United States, making up about 96% of the cat population. They are also referred to as house cats or alley cats.

Siamese cat: The Siamese cat is a recognized breed that originated from Thailand. It became popular in Europe and North America in the 19th century. The modern-style Siamese has distinct features like blue almond-shaped eyes, a triangular head, large ears, and a slender and muscular body. There are also traditional Siamese cats with rounder heads. The breed is described as affectionate, intelligent, and playful, seeking human interaction and enjoying the company of other cats.

American Brahman: The American Brahman is a breed of beef cattle in the United States. It was developed from Indian cattle, mainly Gir, Guzerá, and Nelore, with some other breeds. The Brahman is known for its ability to tolerate heat, sunlight, and humidity, as well as its resistance to parasites. It has been exported to many countries and is the most common breed in Australia. The Brahman has also been used to create other hybrid breeds such as Brangus and Brahmousin.

Hereford cattle: The Hereford cattle is a British beef breed from Herefordshire in England. It was developed through selective breeding by families in Herefordshire from the mid-18th century, predating Robert Bakewell's notable work.

Holstein Friesian: The Holstein Friesian is a highly popular breed of dairy cattle found in over 160 countries. Originating in northern Germany and Dutch provinces, it is dominant in industrial dairy farming globally. Also known as Holstein, Friesian or Black and White, it is recognized for its milk production capabilities.

Gun dog: Gun dogs, also known as bird dogs, are hunting dogs specialized in locating and retrieving game. These canines are trained to assist hunters using firearms and are classified into three categories: pointers and retrievers, setters and spaniels, and water dogs.

Herding dog: A herding dog, also called stock or shepherd dog, is trained or bred to excel in herding. These dogs possess skills and instincts that enable them to control and guide livestock efficiently.

Hound: A hound is a hunting dog bred for tracking and chasing prey. Hunters rely on hounds to pursue and locate their targets.

Livestock guardian dog: A Livestock guardian dog (LGD) is a specialized breed of dog that protects livestock from predators.

Mastiff: A mastiff is a powerful type of dog known for its large size, short coat, and long low-set tail. They have a broad and short muzzle, drooping ears, and big feet. Mastiffs have been used as guard dogs for centuries, protecting homes and property. They have also been used as hunting dogs and war dogs. Historical records show that mastiffs have been involved in blood sports, such as fighting other animals like bulls, bears, and even lions.

Spitz: Spitz: A domestic dog with 68 breeds known for long, thick fur, pointed ears and muzzles. Their tails curl or droop, and smaller breeds resemble foxes while larger ones resemble jackals, coyotes, wolves, and dingoes.

Terrier: Terriers are small, wiry, and fearless dogs bred to hunt vermin. They come in various breeds and sizes, ranging from 1 kg to over 60 kg. Terrier breeds are categorized by size or function and can belong to one of five different groups, each with distinct shapes and sizes.

Arabian horse: The Arabian horse is a distinct breed with roots in the Arabian Peninsula. Known for its unique head shape and high tail carriage, it is one of the oldest horse breeds. Archaeological evidence dates back 3,500 years showing similar horses. Arabian horses have had a global impact through war and trade, improving other breeds with their speed, endurance, and strong bone. Their bloodlines can now be found in almost every modern breed of riding horse.

Andalusian horse: The Andalusian, also known as the Pure Spanish Horse or PRE, is a horse breed from the Iberian Peninsula. It has been recognized as a distinct breed since the 15th century and has maintained its conformation over the centuries. Prized by nobility for its prowess in warfare, it was used in diplomacy and spread throughout Europe. However, herd numbers declined due to warfare, disease, and crossbreeding in the 19th century. While exports were restricted until the 1960s, the breed has since spread worldwide, despite its low population. As of 2010, there were over 185,000 registered Andalusians worldwide.

Friesian horse: The Friesian horse is a breed from the Netherlands, known for its black coat color, long mane and tail, feathering on legs, high head carriage, and high stepping action. Classified as a light draught horse, it almost went extinct multiple times but is now commonly used for riding and driving.

Thoroughbred: The Thoroughbred is a breed of horse known for its agility, speed, and spirit. Developed specifically for horse racing, Thoroughbreds are considered "hot-blooded" horses. Although the term is sometimes used more broadly, it technically refers only to this breed.

Pony: A pony is a small horse with specific conformation and temperament. It may have a thicker coat, mane, tail, shorter legs, wider barrel, heavier bone, thicker neck, and broader head compared to larger horses. The term "pony" originated from the old French word for foal, meaning a young and immature horse.

Mule: A mule is a hybrid animal resulting from the breeding of a male donkey and a female horse. It cannot reproduce due to the different number of chromosomes in the horse and donkey. Mules are more easily obtainable and common compared to another hybrid called a hinny, which is the offspring of a female donkey and a male horse.

Merino: Merino is a group of domestic sheep known for their soft and fine wool. Originating in Spain during the Middle Ages, it was strictly controlled by the Spanish monarchy. In the 18th century, the breed was introduced to various European countries. Over time, Merinos spread to different parts of the world like South Africa, Australia, and New Zealand. Today, the breed has diversified into many recognized types, including American Merino, Australian Merino, and Rambouillet in Europe.

Mammal: Mammals are vertebrate animals with milk-producing mammary glands, a neocortex in the brain, fur or hair, and three middle ear bones. They differ from reptiles and birds and have over 6,400 described species divided into 29 orders. Mammals evolved over 300 million years ago from ancestors in the Carboniferous Period.

Pangolin: Pangolins are scaly anteaters, belonging to the order Pholidota. They are mammals with three genera, Manis, Phataginus, and Smutsia, found in Asia and sub-Saharan Africa. They vary in size, ranging from 30 to 100 cm. In addition to the existing species, there are also several extinct pangolin species. As of September 2023, a total of nine species have been reported.

Proboscidea: Proboscidea is a taxonomic order of Afrotherian mammals that includes the elephants and their close relatives. It consists of one living family (Elephantidae) and various extinct families. Proboscideans are known for being some of the largest land mammals, with the extinct elephant Palaeoloxodon namadicus possibly being the largest ever, estimated to be up to 5.2 m (17.1 ft) tall and weigh up to 22 t. The African bush elephant is the largest living proboscidean, reaching a height of 4 m (13.1 ft) and weighing 10.4 t. Notably, proboscideans have tusks and long, muscular trunks, which were less developed or absent in earlier species.

Elephant: Elephants are the largest land animals, with three species: African bush elephant, African forest elephant, and Asian elephant. They belong to the family Elephantidae and order Proboscidea, and are known for their long trunk, tusks, pillar-like legs, and tough yet sensitive grey skin. The trunk is prehensile and used for feeding and grasping objects, while tusks serve as weapons and tools. Their large ear flaps help regulate body temperature and communicate. African elephants have larger ears and concave backs, whereas Asian elephants have smaller ears and convex or level backs.

Mammoth: Mammoths were extinct elephantids with long, curved tusks that lived from the Pliocene to the Holocene. They had various species present across Africa, Europe, Asia, and North America. Mammoths are closely related to Asian elephants rather than African elephants.

Sirenia: Sirenia, also known as sea cows or sirenians, are fully aquatic, herbivorous mammals that inhabit various water bodies. They belong to the order Sirenia and have two living families, Dugongidae and Trichechidae, with four species in total. They evolved around 50 million years ago in the Eocene and are closely related to elephants and hyraxes. Dugongidae and Trichechidae diverged in the late Eocene or early Oligocene.

Aardvark: The aardvark is a nocturnal, burrowing mammal found in Africa. It is the sole living member of the order Tubulidentata with a distinctive pig-like snout, allowing it to locate food.

Hyrax: Hyraxes, known as dassies, are small, herbivorous mammals resembling pika and marmots. They have fur, short tails, and measure 30-70 cm in length, weighing between 2-5 kg. Surprisingly, hyraxes are closely related to elephants and sea cows.

Bat: Bats, belonging to the Chiroptera order, are the only mammals capable of sustained flight. With adapted forelimbs as wings, they possess agile flight abilities surpassing most birds. Their long digits are covered in a thin membrane, allowing them to achieve flight. The smallest bat is Kitti's hog-nosed bat, measuring 29-34mm in length and weighing 2-2.6g. Conversely, the flying foxes, such as the giant golden-crowned flying fox, can reach a weight of 1.6kg and possess a wingspan of 1.7m.

Megabat: Megabats, also known as fruit bats or flying foxes, belong to the family Pteropodidae in the order Chiroptera. They are the only member of the superfamily Pteropodoidea and are part of the suborder Yinpterochiroptera. There are currently 197 known species of megabats.

Pteropus: Pteropus is a genus of large bats, also known as fruit bats or flying foxes. They reside in South Asia, Southeast Asia, Australia, East Africa, and some islands in the Indian and Pacific Oceans. With over 60 species, Pteropus is recognized as one of the largest bat genera globally.

Microbat: Microbats are a suborder of bats known as Microchiroptera. They are differentiated from Megachiroptera (megabats) based on their size and use of echolocation. Molecular evidence suggests that microbats form a paraphyletic group.

Vampire bat: Vampire bats are leaf-nosed bats found in Central and South America. They have a unique diet of blood, known as hematophagy. There are three existing species: the common, hairy-legged, and white-winged vampire bats. Two extinct species were found in North America.

Carnivora: Carnivora is a major order of mammals known as carnivorans. They are specialized in consuming flesh and make up the fifth largest order, with over 279 species.

Bear: Bears are dog-like carnivores found in North America, South America, and Eurasia. They have large bodies, stocky legs, and long snouts. They also possess shaggy hair, round ears, and plantigrade paws with nonretractile claws. There are eight extant bear species, adapted to a wide range of habitats in the Northern and Southern Hemispheres.

Brown bear: The brown bear is a large bear found in Eurasia and North America. It is one of the largest terrestrial carnivores, second only to the polar bear. Their range spans across several countries, including Russia, China, Canada, United States, Iran, and Europe. In North America, they are called grizzly bears, and the subspecies in Kodiak Islands is known as Kodiak bear.

Giant panda: The giant panda is a bear species endemic to China, recognized for its distinctive black-and-white coat. It mainly eats bamboo, but may also consume grasses, tubers, and occasionally even meat. Although part of the Carnivora order, it is a folivore. Giant pandas in captivity may be fed a variety of foods, including honey, eggs, fish, yams, shrub leaves, oranges, and bananas.

Polar bear: The polar bear is a large bear found in the Arctic and nearby regions. It is closely related to the brown bear. Adult males can weigh 300-800 kg and are the largest carnivores on land. Females are smaller. The polar bear has white- or yellowish-fur, black skin, and a thick layer of fat. It is slimmer than the brown bear, with a narrower skull, longer neck, and lower shoulder hump. Its sharp teeth are adapted for cutting meat. The bear's large paws allow it to walk on ice and swim in water.

Canidae: Canidae is a family of dog-like carnivores known as canids. It consists of three subfamilies: Caninae, Borophaginae (extinct), and Hesperocyoninae. Caninae are called canines and include domestic dogs, wolves, coyotes, foxes, jackals, and other species.

Coyote: The coyote is a smaller species of canine native to North America, similar in size to the eastern wolf and red wolf. It is larger and more predatory than the golden jackal in Eurasia and has been referred to as the American jackal. Historical names for the coyote include the prairie wolf and the brush wolf.

Dog: The dog is a domesticated mammal descended from the wolf. It was the first species to be domesticated over 15,000 years ago by hunter-gatherers in Oberkassel, Bonn. Dogs have a close relationship with humans and have adapted to thrive on a starch-rich diet.

Dingo: The dingo is an ancient dog species found in Australia. Its classification is debated, with various scientific names used. It is considered either a form of domestic dog, a subspecies of dog or wolf, or a distinct species.

Fox: Foxes are medium-sized mammals belonging to the Canidae family. They have flattened skulls, triangular ears, pointed snouts, and long bushy tails. They are omnivorous.

Jackal: Jackals are medium-sized canids found in Africa and Eurasia. "Jackal" typically refers to three species: the black-backed jackal, side-striped jackal, and golden jackal. The African golden wolf was previously classified as a jackal as well.

Wolf: The wolf, also known as the gray wolf, is a large canine native to Eurasia and North America. It is the largest member of the Canidae family and has distinguishable features like less pointed ears, a shorter torso, and a longer tail. Wolves have more than thirty recognized subspecies, including the dog and dingo. Their fur is usually mottled with various colors, but arctic subspecies can be mostly white. Wolves are closely related to smaller Canis species and can produce fertile hybrids with them.

Felidae: Felidae is a family of mammals known as cats. They belong to the order Carnivora. Felidae includes both wild and domestic cats, and they are commonly referred to as felids. The term "cat" can be used to describe all felids as well as specifically the domestic cat.

Cat: The cat, a domesticated species in the Felidae family, originated in the Near East around 7500 BC. It is commonly kept as a house pet or farm cat, but can also live as a feral cat. Valued for companionship and hunting vermin, it has retractable claws and is skilled at killing small prey. With a strong body, quick reflexes, sharp teeth, and enhanced night vision and smell, cats are solitary hunters and active during dusk and dawn. They communicate through various vocalizations and body language, and possess exceptional hearing and the ability to sense pheromones.

Cheetah: The cheetah is a large cat known for its tawny or creamy white fur with solid black spots. It has a small, rounded head with tear-like facial streaks. With a height of 67–94 cm at the shoulder and a length of 1.1–1.5 m, it weighs between 21 and 72 kg. Considered the fastest land animal, it can reach speeds of 93 to 104 km/h. The cheetah has evolved specialized features like a light build, long thin legs, and a long tail that enable it to run at such high speeds.

Cougar: The cougar, also known as the puma or mountain lion, is a large cat native to the Americas. It is the second largest cat after the jaguar and is not considered a "true" big cat due to its smaller size and inability to roar. The cougar's range spans from Canadian provinces to the Western United States and further south into Mexico, the Amazon Rainforest, and the southern Andes Mountains in Patagonia. It is widely distributed across Central and South America, making it the most widely distributed large terrestrial mammal in the Western Hemisphere. The cougar is an adaptable species that can live in various habitats, including dense underbrush and rocky areas.

Lynx: A Lynx is a medium-sized wild cat genus. There are four extant species. The name comes from the Greek word "lynx," referring to its reflective eyes.

Jaguar: The jaguar is a large cat species found in the Americas. It is the largest cat in the Americas and the third largest in the world. With a distinct coat featuring yellow-tan fur and spots that transition to rosettes, it also has a black variant. Jaguars can pierce turtle shells and employ a unique killing method by delivering a fatal bite to the brain.

Leopard: The leopard is a member of the Panthera genus, known for its pale yellowish to dark golden fur with dark spots in rosettes. It has a slender and muscular body, measuring 92-183 cm in length with a 66-102 cm long tail and a shoulder height of 60-70 cm. Males weigh an average of 30.9-72 kg, while females weigh around 20.5-43 kg.

Lion: The lion is a large cat found in Africa and India. It has a powerful build, a round head, round ears, and a hairy tail. Male lions are larger and have a mane. Lions live in groups known as prides, consisting of adult males, related females, and cubs. Females hunt in groups, targeting large animals. Lions are apex predators, but they rarely seek out or prey on humans.

Snow leopard: The snow leopard, also known as the ounce, is a large cat species native to Central and South Asia. With a population of fewer than 10,000 mature individuals, it is listed as Vulnerable on the IUCN Red List. Its main threats come from poaching and habitat destruction due to development. Found in alpine and subalpine zones at elevations of 3,000–4,500 m (9,800–14,800 ft), the snow leopard resides in areas ranging from Afghanistan to Siberia and China.

Tiger: The tiger is the largest living cat species, recognized by its orange fur with dark vertical stripes and a white underside. It is an apex predator that mostly hunts ungulates like deer and wild boar. Tigers are solitary but social predators, requiring large areas of habitat for prey and raising their offspring. Tiger cubs stay with their mother for about two years before becoming independent and establishing their own territory.

Mustelidae: The Mustelidae, or mustelids, are carnivorous mammals that include weasels, badgers, otters, martens, grisons, and wolverines. They form the largest family in the Caniformia suborder of Carnivora, with around 66 to 70 species divided into nine subfamilies.

European badger: The Eurasian badger, also known as the European badger, is a species in the Mustelidae family. It is native to Europe, West Asia, and parts of Central Asia. The European badger has a large, stable population and is classified as least concern on the IUCN Red List. It is the predominant badger species in Europe, often referred to simply as "badger."

Honey badger: The honey badger, known as the ratel, is a mammal found across Africa, Southwest Asia, and the Indian subcontinent. It is considered Least Concern on the IUCN Red List due to its widespread distribution and ability to adapt to various habitats.

Marten: A marten is a weasel-like mammal in the genus Martes that belongs to the family Mustelidae. They have bushy tails, partially retractile claws, and their fur varies from yellowish to dark brown. These slender and agile animals are well adapted to living in the taiga and can be found in coniferous and northern deciduous forests across the Northern Hemisphere. Martens are highly valued for their fur in the animal trapping industry.

Otter: Otters are carnivorous mammals belonging to the subfamily Lutrinae. They are semiaquatic, aquatic, or marine and primarily feed on fish and invertebrates. Lutrinae is a subdivision of the Mustelidae family, which encompasses various animals like weasels, badgers, mink, and wolverines.

Sea otter: The sea otter is a heaviest member of the weasel family found in the North Pacific Ocean. It weighs between 14 and 45 kg and has an extremely dense fur coat for insulation. The sea otter can live solely in the ocean but also walk on land.

Weasel: Weasels are small, active predators with long and slender bodies and short legs. They belong to the genus Mustela, which includes polecats, stoats, ferrets, and European mink. The family Mustelidae is commonly known as the "weasel family". In the UK, the term "weasel" typically refers to the least weasel, the smallest species in the carnivore group.

Stoat: The stoat, also known as the Eurasian ermine, is a mustelid native to Eurasia and parts of North America. It was introduced into New Zealand to control rabbits but had a negative impact on native bird populations. This widely distributed species is listed as Least Concern on the IUCN Red List and has been recognized as one of the world's top 100 "worst invaders."

Wolverine: The Wolverine, also known as the glutton or carcajou, is the biggest land-dwelling species in the Mustelidae family. It is a powerful carnivore that lives alone. Despite its small size, the wolverine is infamous for its incredible ferocity and strength, capable of overpowering prey much larger than itself.

Pinniped: "Pinnipeds, or seals, are a diverse group of carnivorous marine mammals that have adapted to a semi-aquatic lifestyle. They are widely distributed and consist of three extant families, Odobenidae, Otariidae, and Phocidae, with a total of 34 species. Pinnipeds were previously believed to have descended from two different evolutionary lines, but recent molecular evidence suggests they form a single lineage. They belong to the suborder Caniformia of the order Carnivora and share a common ancestry with musteloids, having diverged approximately 50 million years ago."

Eared seal: Eared seals, also known as otariids or otaries, are a family of marine mammals called Otariidae. They consist of 15 species in seven genera, including sea lions and fur seals. Eared seals are different from true seals and walruses. They have adapted to a semi-aquatic lifestyle, spending time in water for feeding and migrating, while breeding and resting on land or ice. They can be found in subpolar, temperate, and equatorial waters across the Pacific and Southern Oceans, as well as the southern Indian and Atlantic Oceans. However, they are absent in the north Atlantic.

Earless seal: Earless seals, also known as phocids or true seals, are a group of mammals within the seal lineage, Pinnipedia. They are distinguished from fur seals and sea lions and belong to the family Phocidae. True seals inhabit the oceans of both hemispheres, predominantly in polar, subpolar, and temperate climates. With the exception of the Baikal seal, which exclusively lives in freshwater, they primarily reside in marine environments.

Walrus: The walrus is a large marine mammal found in the Arctic and subarctic regions. It is the only species in the family Odobenidae and is divided into two subspecies: the Atlantic and Pacific walrus, each living in different oceans.

Procyonidae: Procyonidae is a family of New World carnivores, including raccoons, coatis, and kinkajous. They are omnivorous and inhabit diverse environments.

Hyena: Hyenas are carnivorous mammals belonging to the family Hyaenidae. They are a small family in the Carnivora order and play an essential role in African ecosystems.

Smilodon: Smilodon is an extinct genus of saber-toothed felids that lived in the Americas during the Pleistocene epoch. Often referred to as the saber-toothed tiger, it was not closely related to modern tigers or other cats. The genus was named in 1842 and three species are recognized: S. gracilis, S. fatalis, and S. populator. The largest collection of Smilodon fossils comes from the La Brea Tar Pits in Los Angeles.

Skunk: Skunks are mammals known for their ability to spray a strong-smelling liquid from their anal glands. They belong to the family Mephitidae and come in different appearances, such as black-and-white, brown, cream, or ginger colored. Skunks possess warning coloration.

Mongoose: A mongoose is a small carnivorous mammal that belongs to the family Herpestidae. It is split into two subfamilies, with 23 living species found in southern Europe, Africa, and Asia. The family originated about 21.8 million years ago in the Early Miocene and genetically diverged into two main lineages around 19.1 million years ago.

Hedgehog: A hedgehog is a spiny mammal found in Europe, Asia, Africa, and New Zealand. There are 17 species in 5 genera. They are not native to Australia or the Americas, except for the extinct genus Amphechinus in North America.

Mole (animal): Moles are small mammals that live underground and have cylindrical bodies, velvety fur, small eyes and ears, short hindlimbs, and powerful forelimbs with large digging paws.

Shrew: Shrews are small mole-like mammals in the order Eulipotyphla. They should not be confused with other shrew-like animals, such as treeshrews, otter shrews, and elephant shrews, which belong to different families or orders.

Artiodactyl: Artiodactyls are mammals that belong to the order Artiodactyla. They are typically ungulates that distribute weight evenly on their third and fourth toes. Unlike perissodactyls, they have an even number of toes and often digest plant cellulose in specialized stomach chambers. Recent findings show that cetaceans, like whales and dolphins, are closely related to hippos and fall under this group. Some use the name Cetartiodactyla to include cetaceans, while others keep them separate.

Ruminant: A ruminant is a herbivorous animal that can digest and extract nutrients from plant-based food by fermenting it in a specialized stomach. This process, called foregut fermentation, involves regurgitating and chewing the fermented food again. This rechewing, known as rumination, helps break down plant matter and aids digestion. The term "ruminant" comes from the Latin word "ruminare," meaning "to chew over again."

Bovidae: Bovidae is a family of cloven-hoofed, ruminant mammals that includes various animals like cattle, bison, antelopes, and more. They have 143 living species and 300 known extinct species. The family originated 20 million years ago in the early Miocene and is divided into 11 subfamilies and thirteen tribes. The term 'bovid' refers to a member of this family.

African buffalo: The African buffalo is a large bovine found in sub-Saharan Africa. It has five recognized subspecies, including the Cape buffalo, the largest one found in Southern and East Africa. The smallest subspecies is common in forest areas of Central and West Africa. The African buffalo's distinct feature is its fused horn bases that form a continuous bone shield on top of the head known as a "boss."

Antelope: Antelopes are diverse ruminant animals belonging to the Bovidae family. They are found in Africa, India, the Middle East, Central Asia, and parts of Eastern Europe. While not forming a monophyletic group, antelopes are closely related to bovines, goats, and sheep within the Bovidae family.

Gazelle: A gazelle is a type of antelope, with multiple species in the genera Gazella, Eudorcas, Nanger, and Procapra. Gazelles are found mainly in Africa and Asia.

Impala: The impala is a medium-sized antelope found in eastern and southern Africa. It is the only extant member of the genus Aepyceros. Two subspecies are recognized, the common impala in grasslands and the black-faced impala in scrubland. The impala measures 70-92 cm at the shoulder, weighs 40-76 kg, and has a glossy reddish-brown coat. The male impala has slender, lyre-shaped horns measuring 45-92 cm in length.

Wildebeest: The wildebeest, also known as gnu, is an antelope species native to Eastern and Southern Africa. They belong to the Bovidae family, along with other hoofed mammals like antelopes, cattle, goats, and sheep. There are two species of wildebeest: the black wildebeest or white-tailed gnu, and the blue wildebeest or brindled gnu.

Aurochs: The aurochs is an extinct cattle species, serving as the wild ancestor of modern domestic cattle. It was among the largest herbivores of the Holocene, with males reaching heights of 180 cm (71 in) and females reaching heights of 155 cm (61 in). It possessed long, wide horns that measured around 80 cm (31 in) in length.

Capra(genus): Capra is a mammal genus consisting of ten species, including the markhor and various ibexes. This genus also includes the domestic goat, which has been domesticated for over 8,500 years from the wild goat.

Goat: The goat is a domesticated species of goat-antelope belonging to the Bovidae family. It is closely related to sheep and has over 300 distinct breeds. It was domesticated from the wild goat of Southwest Asia and Eastern Europe and is one of the oldest domesticated animals, with earliest evidence of domestication in Iran around 10,000 years ago.

Cattle: Cattle are domesticated, large ungulates that belong to the subfamily Bovinae. They are widespread and prominent members of the genus Bos. Bulls are mature males, cows are mature females, and young cattle are often colloquially referred to as cows, including heifers, bullocks, and steers.

Gaur: The gaur, an Indian bison native to South and Southeast Asia, is classified as Vulnerable on the IUCN Red List. Its global population of around 21,000 mature individuals is mostly found in India.

Muskox: The muskox, a hoofed mammal of the Bovidae family, is native to the Arctic. It is known for its thick coat and the strong odor emitted by males during mating season. This musky scent helps attract females. In Inuktitut, its name "umingmak" translates to "the bearded one."

Sheep: Sheep are domesticated ruminant mammals commonly kept as livestock. They belong to the order Artiodactyla and are the most numerous species of sheep, with over one billion individuals. In everyday usage, the term sheep usually refers to domesticated sheep, although it can also include other species in the genus Ovis. They have different names depending on their gender and age: adult females are called ewes, intact males are rams or occasionally tups, castrated males are wethers, and young sheep are lambs.

Water buffalo: The water buffalo, also known as the domestic water buffalo or Asian water buffalo, is a large bovid native to the Indian subcontinent and Southeast Asia. It can now be found in several other regions including Italy, the Balkans, Australia, North America, South America, and some African countries. The water buffalo is classified into two main types: the river buffalo, present in India, the Balkans, Egypt, and Italy, and the swamp buffalo, found from Assam to China. These classifications are based on their physical characteristics and behavior.

Yak: The yak is a domesticated long-haired cattle species found in the Himalayan region, Tibetan Plateau, Gilgit-Baltistan, Tajikistan, Mongolia, and Siberia. It is known as the Tartary ox or hairy cattle and is descended from the wild yak.

American bison: The American bison, known as the buffalo, is a native species to North America. It is one of two remaining bison species, with the European bison being the other. Historically, the American bison roamed a vast grassland known as the great bison belt, stretching from Alaska to the Gulf of Mexico and east to the Atlantic Seaboard. Sightings of American bison have been reported as far north as New York and as far south as Florida.

European bison: The European bison, also known as the wisent or zubr, is a species of bison native to Europe. It is the heaviest land animal in Europe and shares its classification with the American bison. During late antiquity and the Middle Ages, the European bison became extinct throughout most of Europe and Asia. Today, it survives only in northern-central Europe and the northern Caucasus Mountains. By the early 20th century, bison were hunted to extinction in the wild.

Alpaca: The alpaca is a smaller species of South American mammal often mistaken for a llama. It can crossbreed with llamas and is believed to have been domesticated from wild relatives. There are two breeds: Suri and Huacaya alpacas.

Guanaco: The guanaco is a South American camelid, closely related to the llama. It is one of two wild camelid species in South America, with the other being the vicuña, found at higher elevations.

Llama: The llama: a domesticated South American camelid, used for meat and as a pack animal by Andean cultures since ancient times.

Vicuña: The vicuña is a wild South American camelid that lives in the Andes. It is closely related to llamas and is believed to be the wild ancestor of domesticated alpacas. Vicuñas produce small amounts of extremely fine wool, which is very expensive. The Inca highly valued their wool and wearing vicuña garments was exclusive to royalty. Today, the vicuña is the national animal of Peru.

Camel: Camels are even-toed ungulates with distinctive fatty humps on their backs. They have been domesticated and are used for food, textiles, and transportation in desert habitats. There are three species of camels: the one-humped dromedary (94% of the population), the two-humped Bactrian camel (6% of the population), and the critically endangered wild Bactrian camel.

Bactrian camel: Bactrian camel, also known as the Mongolian camel, is a two-humped camel native to Central Asia. It has a population of 2 million, mostly in domestication. Named after the historical region of Bactria, it differs from the single-humped dromedary.

Dromedary: The dromedary, also called Arabian camel, is a large even-toed ungulate with a single hump on its back. It belongs to the Camelus genus.

Cetacea: Cetacea is an infraorder of aquatic mammals, including whales, dolphins, and porpoises. They have a fully aquatic lifestyle, streamlined bodies, large size, and carnivorous diet. These animals use their tail with a paddle-like fluke for propulsion and their flipper-shaped forelimbs for maneuvering in water.

Whale: Whales are fully aquatic mammals that belong to the order Cetartiodactyla, along with dolphins and porpoises. They are large members of the infraorder Cetacea, excluding dolphins and porpoises. Whales diverged from hippos around 54 million years ago. There are two groups of whales: baleen whales (Mysticeti) and toothed whales (Odontoceti). Mysticetes consist of four families, while Odontocetes include dolphins, porpoises, and six additional families.

Blue whale: The blue whale is the largest animal ever recorded, measuring up to 29.9 meters (98 ft) and weighing up to 199 tonnes. It is a marine mammal with a long and slender body, varying shades of greyish-blue on top and lighter underneath. It has four recognized subspecies found in different ocean regions. Additionally, there may be a fifth subspecies off the coast of Chile.

Humpback whale: The humpback whale is a large baleen whale known for its unique body shape, long pectoral fins, and tubercles on its head. It is the only species in the Megaptera genus, reaching lengths of 14-17m and weighing up to 40 metric tons. This whale is famous for its breaching and other distinct surface behaviors, making it a favorite for whale watchers. Males of this species produce a complex song lasting anywhere from 4 to 33 minutes.

Dolphin: A dolphin is an aquatic mammal belonging to the infraorder Cetacea. There are 40 extant species of dolphins, categorized into families Delphinidae, Platanistidae, Iniidae, and Pontoporiidae, and possibly extinct Lipotidae.

Orca: The orca, or killer whale, is the largest member of the oceanic dolphin family. It is a toothed whale with a black-and-white patterned body. Orcas are found worldwide, from Arctic to Antarctic regions and tropical seas.

Porpoise: Porpoises are small cetaceans closely related to narwhals and belugas. They are smaller toothed whales and distinct from dolphins due to their flattened, spade-shaped teeth and lack of pronounced beaks. There are eight existing species of porpoise, and they belong to the Cetartiodactyla clade, along with other cetaceans and even-toed ungulates.

Sperm whale: The sperm whale is the largest toothed predator and a member of the toothed whale family. It is the only living species in its genus, Physeter, and one of three current species in the sperm whale family, including the pygmy and dwarf sperm whales.

Deer: Deer, a ruminant mammal, belongs to the Cervidae family. There are two main groups: Cervinae (including elk and red deer) and Capreolinae (including reindeer and white-tailed deer). All male deer and female reindeer grow and shed antlers annually, distinguishing them from permanently horned antelope in a separate family.

Red deer: The red deer is one of the largest deer species, found in Europe, Asia, and Northern Africa. Males are called stags or harts, while females are called hinds. They have been introduced to other regions, including Australia, New Zealand, and the Americas. Red deer are hunted for their venison meat.

Elk: The elk, also known as wapiti, is a large deer species found in North America and Central and East Asia. It is the second largest member of the deer family, Cervidae, and one of the biggest land mammals in its native range. The term "elk" originally referred to a European moose species but was later used for the Cervus canadensis by North American settlers. The name "wapiti" comes from Native American words meaning "white rump," referring to its distinctive light-colored fur on the rear region.

Moose: The moose, also known as the elk, is the tallest land animal in North America and the world's tallest and heaviest deer. It is the only species in the genus Alces. Adult male moose have broad, palmate antlers, distinguishing them from other deer. They inhabit boreal forests and thrive in cooler climates.

Reindeer: The reindeer, or caribou, is a deer species found in regions of Northern Europe, Siberia, and North America. It has a circumpolar distribution and inhabits Arctic, subarctic, tundra, boreal, and mountainous areas. It belongs to the genus Rangifer and recent studies propose identifying six distinct species within this group.

Giraffe: The giraffe is the tallest living terrestrial animal and the largest ruminant on Earth. It belongs to the genus Giraffa and was traditionally believed to be one species with nine subspecies. However, recent research suggests there may be up to eight extant species. The giraffe is an African mammal with both mitochondrial and nuclear DNA variations, as well as distinct morphological measurements. Additionally, seven extinct species of Giraffa are known from fossils.

Sus(genus): Sus is the genus of wild and domestic pigs, including the common Eurasian wild boar and other species. It is part of the Suidae family, which also includes babirusa, pygmy hog, warthogs, and other pig genera from Africa. Sus species are native to Eurasia and Africa, and are closely related to peccaries.

Pig: The pig, also known as swine or hog, is a domesticated mammal that belongs to the genus Sus. It is an omnivore and has a long, pointed head. Adult pigs can weigh between 50 and 350 kg, but some well-fed individuals can exceed this range. They are distinct from other even-toed ungulates because of their omnivorous diet. Pigs make grunting and snorting sounds.

Wild boar: The wild boar, also called the wild swine or wild pig, is a suid found in Eurasia, North Africa, Americas, and Oceania. It is highly adaptable and widespread, making it one of the most common suiform mammals. Despite being an invasive species in some areas, it is assessed as least concern on the IUCN Red List. Wild boars originated in Southeast Asia and outcompeted other suid species as they spread worldwide.

Peccary: A peccary is a pig-like ungulate found in Central and South America, Trinidad, and southwestern North America. They weigh about 20 to 40 kg and measure between 90 and 130 cm in length. Peccaries are the closest relatives of pigs and are part of the suborder Suina within the Artiodactyla order.

Pronghorn: The pronghorn is an artiodactyl mammal found in western and central North America. It is colloquially known as the American antelope and prong buck due to its resemblance to antelopes. Despite not being a true antelope, it fills a similar ecological role. It is the sole surviving member of the Antilocapridae family.

Hippopotamus: The hippopotamus, commonly known as the hippo, is a large semiaquatic mammal found in sub-Saharan Africa. It belongs to the family Hippopotamidae and is one of two extant species, the other being the pygmy hippopotamus. The name "hippopotamus" comes from the ancient Greek meaning "river horse."

Lagomorpha: Lagomorpha is a taxonomic order of mammals consisting of two families: Leporidae (rabbits) and Ochotonidae (pikas). There are 110 recent species, including rabbits, hares, and pikas. The name comes from the Ancient Greek words for hare and shape.

Hare: Hares, belonging to the genus Lepus, are herbivorous mammals found in Africa, Eurasia, and North America. They live solitarily or in pairs and nest in depressions called forms. Hares are skilled runners with powerful hind legs and large ears for regulating body temperature. The genus includes the largest lagomorphs, and their young are independent and self-sufficient shortly after birth. A young hare is known as a "leveret," while a group is called a "husk," "down," or "drove."

Rabbit: Rabbits, or bunnies, are small mammals belonging to the family Leporidae. They are part of the order Lagomorpha. The European rabbit, Oryctolagus cuniculus, is the most well-known and has been introduced worldwide. There are 305 breeds of domestic rabbits derived from it. Sylvilagus includes 13 wild rabbit species, including seven types of cottontail. Rabbits have significant ecological and cultural impacts across the globe. They are commonly used for food, clothing, as companions, and as a source of inspiration in art.

Marsupial: Marsupials are mammals that belong to the infraclass Marsupialia. They are found in Australasia, Wallacea, and the Americas. Most marsupials carry their young in a pouch. Well-known living marsupials include kangaroos, koalas, opossums, Tasmanian devils, wombats, wallabies, and bandicoots. There are also many extinct marsupial species, such as the thylacine, Thylacoleo, and Diprotodon.

Dasyuromorphia: Dasyuromorphia is an order of carnivorous marsupials found mainly in Australia and some in South America. It includes animals like quolls, dunnarts, the numbat, the Tasmanian devil, and the extinct thylacine. Some extinct kangaroos, thylacoleonids, and members of Sparassodonta were also carnivorous. However, exceptions in Australia are the bandicoots and marsupial moles, which are omnivorous.

Tasmanian devil: The Tasmanian devil is a carnivorous marsupial related to the thylacine. Once found in mainland Australia, it is now only found in Tasmania. It has a stocky build, black fur, and emits a strong odor. It is known for its loud screech and powerful bite. It hunts prey and feeds on carrion.

Opossum: Opossums are marsupials endemic to the Americas, comprising 126 species in 18 genera. They originated in South America and migrated to North America during the Great American Interchange.

Peramelemorphia: Peramelemorphia is an order including bandicoots and bilbies, which are native to Australia-New Guinea. These mammals have a distinct bandicoot shape, with a plump, arch-backed body, long snout, large ears, thin legs, and a tail. They range in size from 140 grams to 4 kilograms, with an average weight of about one kilogram.

Diprotodontia: Diprotodontia is the biggest order of marsupials, comprising around 155 species like kangaroos, wallabies, possums, koalas, and wombats. Notable extinct species include the huge Diprotodon and Thylacoleo, known as the "marsupial lion."

Kangaroo: Kangaroos are four marsupials found in Australia and New Guinea. The term commonly refers to the largest species, the red kangaroo, along with the antilopine, eastern grey, and western grey kangaroos. The Australian government estimates a decline in the kangaroo population from 53.2 million in 2013 to 42.8 million in 2019 within commercial harvest areas.

Koala: The koala, also known as the koala bear, is a herbivorous marsupial native to Australia. It is the only living member of the Phascolarctidae family, with wombats as its closest relatives. Koalas are found in coastal areas of eastern and southern Australia, specifically in Queensland, New South Wales, Victoria, and South Australia. They have a stout, tailless body with a large head, round fluffy ears, and a dark nose. Koalas' body length ranges from 60-85 cm and they weigh between 4-15 kg, with fur colors that can vary from silver grey to chocolate brown. Northern koalas tend to be smaller and lighter in color compared to those further south, possibly indicating separate subspecies but this is a matter of debate.

Monotreme: Monotremes are unique mammals that lay eggs instead of giving birth to live young. The platypus and four species of echidnas are the only existing monotremes. They exhibit distinct structural differences in their brain, jaws, digestive tract, reproductive tract, and other body parts compared to other mammals. Despite laying eggs, female monotremes still nurse their offspring with milk.

Echidna: Echidnas, also known as spiny anteaters, are quill-covered monotremes found in Australia and New Guinea. They are the only living mammals that lay eggs and belong to the order Monotremata, alongside the platypus. Echidnas have a diet that includes ants and termites and are not closely related to true anteaters or hedgehogs. Their offspring are called puggles.

Platypus: The platypus is a unique mammal found in Australia. It is semiaquatic, lays eggs, and has a duck-like bill. It is the only surviving member of its family and genus, with some related species in the fossil record.

Perissodactyla: Perissodactyla is an order of ungulates that includes 17 living species divided into three families: Equidae, Rhinocerotidae, and Tapiridae. They typically have three or one weight-bearing toes and may have present, absent, vestigial, or posteriorly positioned nonweight-bearing toes. Unlike artiodactyls, perissodactyls digest plant cellulose in their intestines instead of stomach chambers.

Rhinoceros: A rhinoceros, often called a rhino, is a large odd-toed ungulate belonging to the family Rhinocerotidae. There are five existing species, two found in Africa and three in South and Southeast Asia. The term can also encompass extinct species of the superfamily Rhinocerotoidea.

Tapir: Tapirs are large, herbivorous mammals similar in shape to pigs, with a short, prehensile nose trunk. They can be found in the jungles and forests of South and Central America, as well as Southeast Asia. Tapirs are one of three branches of Perissodactyla, along with equines and rhinoceroses. Only the genus Tapirus currently exists. They migrated from North America to South America through the Isthmus of Panama during the Pleistocene epoch. Tapirs were once present in North America but became extinct in the Late Pleistocene around 12,000 years ago.

Equidae: Equidae is a family of animals that includes horses, asses, and zebras, as well as other fossil species. They evolved from multi-toed ungulates into single-toed animals around 50 million years ago. All existing species belong to the genus Equus, which originated in North America. Equidae is part of the Perissodactyla order, which includes tapirs, rhinoceros, and extinct families.

Donkey: The donkey, a domesticated equine, comes from the African wild ass known as Equus africanus. It can be classified as a subspecies or a separate species. Domestication occurred in Africa around 5000–7000 years ago. Donkeys have been utilized primarily as working animals throughout history.

Horse: The horse is a domesticated mammal belonging to the Equidae family. It has one toe and has evolved over millions of years into the large, single-toed animal we know today. Humans began domesticating horses around 4000 BCE, and by 3000 BCE, it was widespread. While some domesticated horses live in the wild, true wild horses have never been domesticated. The equine world has a specialized vocabulary to describe various aspects of horses, including their anatomy, life stages, size, colors, markings, breeds, locomotion, and behavior.

Zebra: Zebras are African equines known for their black-and-white striped coats. There are three species: Grévy's, plains, and mountain zebras. They share the same genus as horses and asses. The stripes of zebras are unique to each individual and are believed to deter biting flies. Zebras can be found in various habitats across eastern and southern Africa, including savannahs, grasslands, woodlands, shrublands, and mountains.

Primate: Primates are a diverse order of mammals, divided into strepsirrhines (lemurs, galagos, and lorisids) and haplorhines (tarsiers and simians). They arose 85–55 million years ago from small terrestrial mammals, adapting to life in tropical forests. Key primate characteristics include large brains, sharp vision, color perception, flexible shoulder joints, and dexterous hands. They vary greatly in size, from a 30g mouse lemur to a 200kg eastern gorilla. There are currently 376–524 known primate species, with new discoveries continuing into the present day.

Monkey: Monkeys are mammals in the infraorder Simiiformes, commonly referred to as simians. This term traditionally excludes apes, but in the broader sense, apes are also considered monkeys. Therefore, monkeys form an incomplete paraphyletic group, and the terms monkeys and simians are synonymous in their scope.

Ape: Apes are a group of tailless primates found in sub-Saharan Africa and Southeast Asia. They are divided into two main branches: gibbons (lesser apes) and hominids (great apes). Gibbons are highly arboreal and have smaller social groups, while hominids include orangutans, gorillas, bonobos, chimpanzees, and humans. Apes do not have tails due to a mutation in the TBXT gene. The term "ape" can sometimes include certain tailless primates from the Cercopithecidae family as well, but it is not equivalent to the scientific classification of Hominoidea.

Gibbon: Gibbons are apes found in subtropical and tropical rainforests across Southeast Asia. They belong to the family Hylobatidae, which was originally one genus but is now divided into four genera and 20 species. Their habitat stretches from eastern Bangladesh to northeastern India, southern China, and Indonesia.

Gorilla: Gorillas are large herbivorous apes found in equatorial Africa. There are two species, eastern and western gorillas, with several subspecies. They share 95-99% DNA similarity with humans and are closest to us after chimpanzees and bonobos.

Orangutan: Orangutans are large apes found in the rainforests of Indonesia and Malaysia. They currently reside in Borneo and Sumatra, but used to have a wider range in Southeast Asia and South China. Initially believed to be one species, orangutans were later divided into three: Bornean orangutan, Sumatran orangutan, and Tapanuli orangutan. They are the only surviving species in the Ponginae subfamily, which diverged from other hominids over 15 million years ago.

Pan(genus): The Pan genus includes two species: chimpanzees and bonobos, collectively known as panins. They were previously referred to as "chimpanzees" or "chimps" and "pygmy" or "gracile chimpanzees" respectively. Together with humans, gorillas, and orangutans, they belong to the family Hominidae. Chimpanzees and bonobos are native to sub-Saharan Africa, mainly found in the Congo jungle. Chimpanzees can also be found in West Africa. Both species are endangered according to IUCN and chimpanzees have been granted special protection by the Convention on Migratory Species in 2017.

Chimpanzee: The chimpanzee, or chimp, is a great ape found in tropical Africa. It has four confirmed subspecies and is closely related to humans. Chimpanzees have black hair, bare face, hands, and feet. They are larger and heavier than bonobos, their closest relatives. Males weigh 40-70 kg and females weigh 27-50 kg, standing at 150 cm tall.

Bonobo: The bonobo, also known as the pygmy chimpanzee, is an endangered great ape and a distinct species in the genus Pan. Initially thought to be a subspecies of Pan troglodytes, bonobos share physical similarities with chimpanzees. They are part of the chimpanzee/bonobo subtribe Panina, collectively referred to as panins.

Human: Humans, or modern humans, are bipedal primates with large brains and advanced cognitive skills. They thrive and adapt in diverse environments, using complex tools and forming intricate social structures. Humans are highly social, belonging to various cooperating or competing groups, from families to political states. They possess a strong curiosity, driving advancements in science, technology, philosophy, and religion. With more than 8 billion currently alive, humans are the most widespread and common species.

New World monkey: New World monkeys are primates found in tropical regions of Mexico, Central and South America. They belong to five families: Callitrichidae, Cebidae, Aotidae, Pitheciidae, and Atelidae. These families are ranked together as Ceboidea, the only remaining superfamily in the parvorder Platyrrhini.

Capuchin monkey: The capuchin monkey is a New World monkey found in Central and South America. They are known as the "organ grinder" monkey and have appeared in movies and TV shows. Capuchin monkeys reside in tropical forests in countries like Costa Rica and Panama. In Central America, they are called white-faced monkeys and inhabit wet lowland and deciduous dry forests.

Spider monkey: Spider monkeys, belonging to the genus Ateles, are New World monkeys found in tropical forests of Central and South America. The genus has seven species, all facing threats, especially the critically endangered brown spider monkey. They are known for being easily bred in captivity.

Old World monkey: Old World monkeys, in the Cercopithecidae family, are the largest primate family with 24 genera and 138 recognized species. They include baboons, macaques, and red colobus among others. Other Old World monkeys are known by names like talapoin, guenon, vervet, and mandrill.

Baboon: Baboons are a type of primate in the Papio genus, belonging to the Old World monkeys. There are six different species, including the hamadryas, Guinea, olive, yellow, Kinda, and chacma baboons, each found in specific areas of Africa and the Arabian Peninsula. These baboons have been around for over two million years and are among the largest non-hominoid primates.

Macaque: The term 'Macaque' refers to a genus of gregarious Old World monkeys called Macaca. There are 23 species of macaques distributed across Asia, North Africa, and Europe. They primarily eat fruits and also consume seeds, leaves, flowers, and tree bark. Some species occasionally include small amounts of meat in their diet. Macaques are known to be social animals, with dominant matriarchs leading their social groups.

Rhesus macaque: The rhesus macaque, also known as the rhesus monkey, is a type of Old World monkey. It comes in different colors and sizes, with various subspecies found in China and India. This versatile primate can be found across South, Central, and Southeast Asia, adapting to diverse climates and habitats. Feral populations have also been established in the United States.

Strepsirrhini: Strepsirrhini, a suborder of primates, includes lemurs, galagos, pottos, and lorises. It also encompasses extinct adapiform primates, known as "lemur-like" creatures. Strepsirrhini originated in Africa, with some species spreading to Asia and North America. As the climate cooled, adapiforms disappeared from the Northern Hemisphere.

Galago: Galagos, also known as bush babies or nagapies, are small nocturnal primates found in sub-Saharan Africa. They belong to the Galagidae family and are closely related to the Lorisidae family.

Lemur: Lemurs are primates found only on the island of Madagascar. They belong to the superfamily Lemuroidea, comprising 15 genera and around 100 existing species. With small size, a pointed snout, large eyes, and a long tail, lemurs predominantly inhabit trees and are nocturnal creatures.

Slow loris: The Slow loris is a group of primates found in Southeast Asia known as Nycticebus. They range from Bangladesh to Java and from Yunnan province to the Sulu Archipelago. There are at least eight species: Sunda, Bengal, Javan, Philippine, Bangka, Bornean, Kayan River, and Sumatran slow lorises. The pygmy slow loris is now classified under a different genus. They are closely related to slender lorises, pottos, false pottos, and angwantibos, and distantly related to lemurs. Limited fossil record and inconsistent molecular clock studies make their evolutionary history uncertain.

Tarsier: Tarsiers are primates found in Southeast Asia. They belong to the family Tarsiidae and are the only extant family within the infraorder Tarsiiformes. Originally widespread, they are now only found in Brunei, Indonesia, Malaysia, and the Philippines.

Rodent: Rodents, members of the order Rodentia, are mammals with continuously growing incisors in their upper and lower jaws. They make up about 40% of all mammal species and are found on all major land masses, except New Zealand, Antarctica, and some oceanic islands. Humans have introduced rodents to most of these areas.

Capybara: The capybara is a giant rodent from South America, known as the largest living rodent. It is closely related to guinea pigs and rock cavies. It inhabits savannas and dense forests near water bodies. Capybaras are highly social animals, often found in groups of up to 100 individuals. They are hunted for their meat, hide, and grease from their thick fatty skin.

Nutria: The nutria, also known as the coypu, is a large semi-aquatic rodent from South America. Originally native to South America, it has been introduced to North America, Europe, Asia, and Africa. Nutria live in burrows near water and feed on river plant stems. They are considered an invasive species due to their destructive burrowing and feeding habits, often conflicting with humans. Nutria also transmit diseases through water contamination, posing risks to humans and animals.

Beaver: Beavers are large, semi-aquatic rodents found in the Northern Hemisphere. They are the second-largest living rodents, weighing up to 50 kg. Beavers have stout bodies, long incisors, brown or gray fur, and flat, scaly tails. They differ in skull and tail shape and fur color between the North American and Eurasian species. Beavers inhabit freshwater habitats like rivers, lakes, and ponds, and are herbivorous, feeding on tree bark, aquatic plants, grasses, and sedges.

Dormouse: The dormouse is a nocturnal rodent found in Africa, Asia, and Europe. It belongs to the Gliridae family and is known for its extended hibernation period lasting six months or more.

Guinea pig: The guinea pig, also known as the cavy, is a domesticated rodent native to the Andes region of South America. Despite its name, it is not related to pigs nor is it from Guinea. The animal is commonly used in scientific and laboratory settings, while breeders refer to it as the "cavy." Guinea pigs are believed to be domesticated descendants of a closely related cavy species. Originally bred for meat, they are still consumed in some regions.

Hamster: Hamsters are rodent pets that belong to the subfamily Cricetinae, including 19 species in seven genera. The golden hamster, also known as the Syrian hamster, is the most popular pet species. Other common pet species include three types of dwarf hamsters: Campbell's, Winter White, and Roborovski.

Muridae: The Muridae, or murids, are the largest family of rodents and mammals with around 1,383 species. They include various mice, rats, and gerbils that are native to Eurasia, Africa, and Australia.

Rat: Rats are medium-sized rodents with long tails. They belong to the Rattus genus, although other rat genera include Neotoma, Bandicota, and Dipodomys.

Brown rat: The brown rat, also called the common rat, is a widespread species of rodent. It is one of the largest muroids, measuring up to 28 cm in length with a slightly shorter tail. Weighing between 140 and 500 g, it is brown or grey in color. Originally from northern China, it has now spread to all continents except Antarctica and is prominent in Europe and North America. The brown rat is commonly found wherever humans reside, especially in urban areas.

Mouse: A mouse is a small rodent with a pointed snout, rounded ears, a scaly tail, and a high breeding rate. The common house mouse is the most famous species. Mice are often kept as pets and can invade homes for food and shelter.

Muskrat: The muskrat is a rodent native to North America, but also found in parts of Europe, Asia, and South America. It is a semiaquatic species commonly found in wetlands. This medium-sized animal plays a significant role in wetland ecology and serves as a valuable food and fur resource for humans.

Porcupine: Porcupines are large rodents with sharp spines that protect them from predators. They belong to two different families: the Old World porcupines and the New World porcupines. Both families have similar coats made of rigid or semi-rigid quills. Despite the similarities, the two groups are distinct and not closely related within the rodent order. Porcupines are the third-largest living rodents and have the largest species among them.

Squirrel: Squirrels are small to medium-sized rodents that belong to the family Sciuridae. They come in different types such as tree squirrels, ground squirrels, and flying squirrels. Indigenous to the Americas, Eurasia, and Africa, squirrels were brought to Australia by humans. Fossil evidence shows their existence since the Eocene epoch. Squirrels are closely related to the mountain beaver and dormice within the larger group of living rodents.

Marmot: Marmots are large ground squirrels found in Asia, Europe, and North America. They are herbivores, active in summer and hibernate in winter. Marmots are the heaviest members of the squirrel family.

Anteater: Anteaters are mammal species known for eating ants and termites. They are part of the suborder Vermilingua and are closely related to sloths within the order Pilosa. The term "anteater" is often mistakenly used for unrelated animals such as aardvarks, numbat, echidnas, and pangolins.

Armadillo: The armadillo is a New World placental mammal in the order Cingulata, part of the superorder Xenarthra. There are 21 extant species of armadillo, native to the Americas, with different armor bands. They inhabit various environments in the Americas.

Sloth: Sloths are slow-moving Neotropical mammals that live in the trees of South and Central American rainforests. They consist of arboreal tree sloths and extinct ground sloths. Known for hanging upside down, tree sloths spend their lives in the treetops. They are closely related to anteaters and belong to the xenarthran order Pilosa.

Bird: Birds are warm-blooded vertebrates with feathers, toothless beaked jaws, and the ability to lay hard-shelled eggs. They have a high metabolic rate, a four-chambered heart, and a lightweight yet strong skeleton. Birds can be found worldwide, varying in size from the tiny bee hummingbird to the large common ostrich. There are over 11,000 living species, with more than half being perching birds. Wings, developed from forelimbs, enable most birds to fly, although flight is lost in certain species. Digestive and respiratory systems of birds are adapted for flight, and some species have further adapted for swimming in aquatic environments. The study of birds is known as ornithology.

Bird of prey: Birds of prey, also known as raptors, are hypercarnivorous birds that actively hunt and feed on other vertebrates. They possess strong speed, strength, keen eyesight, sharp talons, and powerful beaks for hunting and tearing flesh. While primarily hunting live prey, they also scavenge and consume carrion.

Palaeognathae: Palaeognathae is an infraclass of birds, also known as paleognaths, which are part of the Archosauria clade in the Aves class. It is one of the two existing infraclasses of birds, alongside Neognathae, together forming Neornithes. Palaeognathae consists of five flightless lineages called ratites, such as the kiwis, cassowaries, emus, rheas, and ostriches, as well as one flying lineage known as the Neotropic tinamous. There are 47 species of tinamous, five of kiwis, three of cassowaries, one of emus, two of rheas, and two of ostriches. Recent studies indicate that paleognaths are monophyletic, and the traditional distinction between flightless and flighted forms is incorrect, as flightlessness developed independently multiple times through parallel evolution within the ratite group, which includes tinamous.

Seabird: Seabirds are marine-adapted birds that show convergent evolution due to similar adaptations to environmental challenges and feeding niches. They first evolved in the Cretaceous period, and modern seabird families emerged in the Paleogene.

Flamingo: Flamingos are wading birds in the family Phoenicopteridae. They belong to the only extant family in the order Phoenicopteriformes. There are four species in the Americas and two species in Afro-Eurasia.

Loon: Loons, also known as divers, are aquatic birds found in North America and northern Eurasia. They belong to the Gavia genus in the Gaviidae family and Gaviiformes order.

Accipiter: Accipiter is a diverse genus of birds of prey in the Accipitridae family, with 49 recognized species. Most species are called goshawks or sparrowhawks, while New World species are known as hawks. They lack a procoracoid foramen, which distinguishes them from other birds in their family. There are two small species, with a large procoracoid foramen, that may be separated in the old genus Hieraspiza based on DNA sequence.

Eagle: The term "Eagle" refers to various birds of prey in the Accipitridae family, including the golden and bald eagles. True eagles are part of the Aquila genus. Out of the 68 eagle species, most are found in Eurasia and Africa. The rest are distributed across North and South America, as well as Australia.

Golden eagle: The golden eagle is a highly distributed bird of prey found in the Northern Hemisphere. It belongs to the family Accipitridae and is well-known for its dark brown plumage and golden-brown nape. With their agility and powerful talons, they hunt various prey including hares, rabbits, and ground squirrels. These eagles have large territories and build nests in high places to breed. They are monogamous, laying up to four eggs and incubating them for six weeks. Juvenile eagles become independent after three months and establish their own territory in around four to five years.

Falcon: Falcons are a diverse group of birds of prey found worldwide, excluding Antarctica. They belong to the genus Falco and encompass approximately 40 species. While closely related raptors were present in Antarctica during the Eocene, true falcons did not inhabit the continent.

Peregrine falcon: The peregrine falcon, also known as the peregrine, is a large bird of prey. It has a blue-grey back, white underparts, and a black head. It is famous for its incredible speed, being able to reach over 320 km/h during hunting. The fastest recorded speed of a peregrine falcon is 389 km/h. Females are significantly larger than males.

New World vulture: New World vultures, also known as condors, are a family of birds of prey found in the Americas. There are seven extant species in five genera, including five vultures and two condors. They are distinct from Old World vultures and have similar appearance and behavior due to convergent evolution. They inhabit warm and temperate areas.

Old World vulture: Old World vultures are found in Europe, Asia, and Africa. They belong to the family Accipitridae, which includes eagles, buzzards, kites, and hawks.

Osprey: The osprey, also known as sea hawk and fish hawk, is a large bird of prey that feeds on fish. It has a wide range of habitats and is diurnal. With a length of over 60 cm and a wingspan of 180 cm, it has brown upperparts and a greyish head and underparts.

Secretarybird: The Secretarybird is a large bird of prey found in Africa. It inhabits open grasslands and savannas. It was described by John Frederick Miller in 1779 and belongs to the Accipitriformes order. It is placed in its own family called Sagittariidae.

Duck: Ducks are waterfowl in the Anatidae family, smaller than swans and geese. They are not a monophyletic group, distinct from swans and geese. Ducks are mostly aquatic birds and can be found in both fresh and sea water.

Mallard: The mallard is a dabbling duck found across temperate and subtropical regions. It has been introduced to several countries. Belonging to the Anatinae subfamily of waterfowl, males have green heads and females have brown-speckled plumage. Both have a speculum on their wings. The mallard is around 50-65 cm long, with a wingspan of 81-98 cm and a bill length of 4.4 to 6.1 cm. It is slightly heavier than other dabbling ducks, weighing 0.7-1.6 kg. Mallards live in wetlands, eat water plants and small animals, and prefer to gather in groups or flocks.

Goose: A goose is a waterbird belonging to the Anatidae family, specifically the genera Anser and Branta. It is related to swans and ducks, with swans being larger and ducks being smaller. Some other bird species, like shelducks, also have "goose" in their names.

Swan: Swans are birds in the family Anatidae, closely related to geese and ducks. They belong to the genus Cygnus and are often grouped with geese in the subfamily Anserinae, forming the tribe Cygnini. Some consider swans as a distinct subfamily called Cygninae.

Hummingbird: Hummingbirds are small birds in the biological family Trochilidae, native to the Americas. They comprise about 366 species and 113 genera, with a wide distribution from Alaska to Tierra del Fuego. Most species are found in Central and South America. Unfortunately, around 28 species are endangered or critically endangered, and many others are experiencing population decline.

Swift (bird): Swifts, belonging to the family Apodidae, are speedy aerial birds. While they resemble swallows, they are not closely related to any passerine species. Found in the order Apodiformes with hummingbirds, true swifts are distinct from the closely related treeswifts, which form a separate family known as Hemiprocnidae.

Nightjar: Nightjars are medium-sized birds in the family Caprimulgidae and order Caprimulgiformes. They have long wings, short legs, and very short bills. They are known as goatsuckers due to a folklore belief that they sucked milk from goats and primarily feed on insects. Some New World species are called nighthawks. The term "nightjar" originally referred to the European species.

Auk: An auk is a bird in the Alcidae family of Charadriiformes order, including murres, guillemots, auklets, puffins, and murrelets. There are 25 existing or recently extinct species categorized into 11 genera.

Gull: Gulls, also known as seagulls, are seabirds in the Laridae family. They are closely related to terns and skimmers, but distantly related to auks and waders. Most gulls were classified under the Larus genus until recently, when multiple new genera were recognized. In some regional dialects, gulls are referred to as mews, which is similar to their names in German, Danish, Swedish, Dutch, Norwegian, and French.

Tern: Terns are slender seabirds found worldwide near bodies of water. They belong to the Laridae family and share similarities with gulls and skimmers. With their long, forked tails, narrow wings, long bills, and short legs, these birds are lightly built. Most species have pale grey and white plumage with a black cap on their heads, although some have dark plumage temporarily. While males and females look the same, young terns differ from adults. During non-breeding periods, terns often display a white forehead and a reduced black cap.

Sandpiper: The Sandpiper is a type of shorebird, part of the Scolopacidae family, which includes other species like curlews and snipes. Sandpipers mainly feed on small invertebrates found in mud or soil. Their bills vary in length, allowing different species to coexist in the same habitat without competing for food, particularly along the coast.

Heron: Heron is a family of long-legged, long-necked birds found in freshwater and coastal areas. There are 72 recognized species, some of which are called egrets or bitterns. Egrets are mainly white or have decorative plumes in breeding plumage. Herons have long beaks. Bitterns are referred to as members of the Botaurus and Ixobrychus genera, along with the zigzag heron in the Zebrilus genus.

Ibis: Ibis are long-legged wading birds found in wetlands, forests, and plains. The term "Ibis" originates from Latin and Ancient Greek. The western cattle egret was misidentified in 1757 as a sacred ibis.

Shoebill: The shoebill, also called the whalebill or whale-headed stork, is a large wading bird in East Africa. It is named after its distinctive shoe-shaped bill. With a stork-like appearance, it was originally classified with storks but is now grouped with pelicans and herons based on genetic evidence. The adult is mainly grey, while juveniles have a brown coloration. It inhabits large swamps in tropical East Africa, from South Sudan to Zambia.

Stork: Storks are large wading birds with long legs, necks, and stout bills. They belong to the Ciconiidae family and the Ciconiiformes order, which previously included herons and ibises. Other families have since been moved to different orders.

Columbidae: Columbidae is a bird family including doves and pigeons. They have stout bodies, short necks, and slender bills. Some species have fleshy ceres. They feed on plants, with some species eating seeds on the ground, while others feed on fruits from branches. Columbidae is the only family in the Columbiformes order. They are found globally, with the highest diversity in the Indomalayan and Australasian regions, often living in close proximity to humans.

Dodo: The dodo was a flightless bird endemic to Mauritius in the Indian Ocean. It is now extinct and was closely related to the Rodrigues solitaire. Both birds belonged to the Raphinae subfamily, which included other extinct flightless birds and is part of the pigeon and dove family. The Nicobar pigeon is the closest living relative. Claims of a white dodo on Réunion were likely based on confusion with the extinct Réunion ibis and depictions of white dodos in paintings.

Passenger pigeon: The passenger pigeon, an extinct species of pigeon, was native to North America. Its name reflects its migratory nature. The mourning dove was often mistaken as its relative, but genetic analysis revealed a closer relationship with the Patagioenas genus.

Rock dove: The rock dove, also known as the rock pigeon or common pigeon, is a member of the Columbidae bird family. It is commonly referred to as the "pigeon", although the domesticated form is more familiar to people. The wild rock dove is the original form of this bird.

River kingfisher: River kingfishers, also known as pygmy kingfishers, are a subfamily of kingfishers found in Africa, Asia, and Australia. They include species that dive for fish, with their origin believed to be in Asia. The common kingfisher is the only species found in Europe and northern Asia.

Hornbill: Hornbills are colorful birds found in Africa, Asia, and Melanesia. They have a distinctive long, downward-curved bill with a sometimes horn-like structure on top. These birds have a unique kidney structure and fused neck vertebrae. They are omnivorous, eating fruits and small animals. Hornbills are monogamous and nest in tree cavities or cliffs. Unfortunately, some hornbill species are endangered, particularly in Southeast Asia.

Hoopoe: The Hoopoe is a colorful bird with a distinctive feathered "crown." It can be found in Africa, Asia, and Europe. There are three living species and one extinct species recognized. Some experts consider all three living species to be the same. The Eurasian hoopoe is abundant and not threatened, but its population is declining in Western Europe. However, its numbers are increasing in the South Sinai region.

Cuckoo: Cuckoos, found in the Cuculidae family of birds, belong to the order Cuculiformes. They include various species like the common cuckoo, roadrunners, koels, malkohas, couas, coucals, and anis. Sometimes, the coucals and anis are classified as separate families. The Cuculiformes order is part of a larger group called Otidimorphae, along with turacos and bustards. With 150 species divided into 33 genera, the Cuculidae family is diverse.

Hoatzin: The Hoatzin is a unique tropical bird found in swamps and forests of South America. It is the only bird in the Opisthocomidae family, under the Opisthocomiformes order. Its taxonomic position remains debated among specialists.

Turaco: Turaco refers to the bird family Musophagidae, also known as "banana-eaters", comprising of plantain-eaters and go-away-birds. In southern Africa, turacos and go-away-birds are commonly called loeries. They have semi-zygodactylous feet, with a flexible fourth toe. Some species have conjoined second and third toes. Musophagids often possess prominent crests and long tails, while turacos are famous for their vivid green and red feathers, thanks to unique pigments.

Galliformes: Galliformes is an order of ground-feeding birds including turkeys, chickens, quail, and others. Known as gallinaceous birds, they play vital roles as seed dispersers and predators in ecosystems. Humans rear them for meat and eggs, while they are also hunted for sport.

Grouse: Grouse are birds in the family Phasianidae, order Galliformes. They belong to the tribe Tetraonini, supported by mitochondrial DNA studies, and are recognized by various ornithological groups.

Guineafowl: Guineafowl are African birds in the Galliformes order, known for their ancient lineage. They evolved after the Cracidae but before the Odontophoridae. A fossil lineage called Telecrex, found in Mongolia, is associated with guineafowl and may have given rise to blood pheasants and eared pheasants. These birds adapted to high-altitude and montane environments with the emergence of the Tibetan Plateau. While most guineafowl species are found only in Africa, the helmeted guineafowl has been introduced and domesticated in various locations.

Peafowl: Peafowl refers to two bird species, Pavo and Afropavo, in the family Phasianidae. Males are called peacocks, females are called peahens, but both are commonly referred to as "peacocks."

Chicken: Chickens are a domesticated species descended from red junglefowl in Southeast Asia. They hybridize with other junglefowl species. Adult males are called roosters or cocks, while younger males are cockerels and castrated males are capons. Adult females are hens and immature females are pullets. Humans keep chickens for food or as pets. They were historically bred for cockfighting and are still used in some areas. Chickens bred for meat are broilers, while those bred for eggs are layers.

Domestic turkey: The domestic turkey is a large fowl, closely related to the wild turkey. It was thought to have been domesticated in central Mesoamerica around 2,000 years ago, with a possible second domestication event in the southwestern United States between 200 BC and 500 AD. All modern domestic turkey varieties can be traced back to the turkeys raised in central Mexico and later brought to Europe by the Spanish in the 16th century.

Common pheasant: The common pheasant is a bird in the pheasant family, known scientifically as Phasianus colchicus. It gets its genus name, Phasianus, from the Latin word for "pheasant". The species name, colchicus, refers to the country Colchis, where pheasants were first discovered by Europeans. Recent studies have found that the common pheasant is not closely related to junglefowl and domesticated chickens, even though they were previously thought to be. They diverged from each other more than 20 million years ago.

Common quail: The common quail is a small migratory game bird found in the western Palearctic. It belongs to the pheasant family, Phasianidae, and nests on the ground. During winter, it migrates to Africa and southern India.

Gruiformes: Gruiformes is an order of birds, including both living and extinct families, characterized by their crane-like appearance. They exhibit a wide geographic distribution.

Crane (bird): Cranes are large birds in the Gruidae family, with long legs and necks. They have 15 species divided among four genera: Antigone, Balearica, Leucogeranus, and Grus. Most cranes have grey or white plumage with black and red patches on the face. However, the Balearica genus exhibits vibrant-colored wings and golden "crowns." Unlike other birds, cranes fly with their necks extended outward and legs stretched out.

Bustard: Bustards are large birds found in dry grasslands and steppes of the Old World. They belong to the family Otididae and range from 40 to 150 cm in length. They include floricans and korhaans.

Rail (bird): Rails are small to medium-sized birds found worldwide, occupying diverse habitats including wetlands, marshes, and forests. They come in various forms and comprise species like crakes, coots, and gallinules. While some rail species are common, others are extremely rare or endangered. Rails are associated with dense vegetation and are known to nest in marshes, rice paddies, and flooded fields. They can be found in all terrestrial habitats except for dry deserts, polar regions, freezing areas, and alpine regions. Rallidae species are present on every continent except Antarctica, and there are numerous unique rail species on different islands.

Passerine: Passerines, also known as perching birds, make up more than half of all bird species. They belong to the order Passeriformes and have an anisodactyl arrangement of their toes, allowing them to perch easily.

Songbird: A songbird, also known as Oscines, is a type of bird belonging to the Passeri suborder of perching birds. They are found worldwide and are known for their complex and diverse bird songs, thanks to their well-developed vocal organs. The Passeriformes group, which includes around 5,000 species, is where songbirds belong.

Bird-of-paradise: The bird-of-paradise is a family of birds known for their colorful plumage and elaborate feathers. They are found in eastern Indonesia, Papua New Guinea, and eastern Australia. There are 45 species in 17 genera. Males have long feathers on the beak, wings, tail, or head, and exhibit sexual dimorphism. They live in dense rainforests and primarily eat fruit and arthropods. Breeding systems vary from monogamy to polygamy.

Corvidae: The Corvidae family is a diverse group of birds including crows, ravens, magpies, and jays. They are commonly known as the crow family or corvids. There are 135 species in this family, with the genus Corvus alone comprising over a third of the entire family. Ravens, which are corvids, are the largest passerine birds.

Corvus: Corvus is a genus of birds in the family Corvidae, including crows, ravens, and rooks. The species commonly found in Europe are carrion crows, hooded crows, common ravens, and rooks. The name "crow" or "raven" is based on their size, with crows generally being smaller. The genus name, Corvus, is derived from the Latin word for "raven."

Common raven: The common raven is a large all-black bird found across the Northern Hemisphere. It is widely distributed and has at least eight subspecies with little variation in appearance. Recent research has revealed significant genetic differences among regional populations. This raven is one of the largest corvids and possibly the heaviest passerine bird. It measures around 63 cm in length and weighs about 1.47 kg. While their typical lifespan is shorter, common ravens can live over 23 years in the wild. They travel in flocks when young but mate for life, defending a territory as a mated pair.

Eurasian magpie: The Eurasian magpie, a member of the crow family, is a resident breeding bird in the northern part of Eurasia. It is part of the "monochrome" magpie group and is often referred to as simply "magpie" in Europe. Unlike the Australian Magpie, the Eurasian magpie is not closely related and is the only magpie found in Europe, aside from the Iberian magpie in the Iberian Peninsula.

Honeyeater: The honeyeaters are a diverse family of small to medium-sized birds, known as Meliphagidae. They are most commonly found in Australia and New Guinea, but can also be found in New Zealand, the Pacific islands and Wallacea. Some notable species include Australian chats, myzomelas, friarbirds, wattlebirds, miners and melidectes. Honeyeaters are known for their wide distribution and are represented by a single species in Bali, situated across the Wallace Line.

Lyrebird: The lyrebird is a ground-dwelling Australian bird known for its ability to mimic sounds from its surroundings. It belongs to the genus Menura and the family Menuridae. The male lyrebird displays a spectacular fanned-out tail during courtship. They have distinct neutral-colored tail feathers and are iconic native birds of Australia.

Shrike: Shrikes are passerine birds in the Laniidae family, consisting of 34 species across two genera.

Bulbul: Bulbuls are medium-sized passerine songbirds that belong to the family Pycnonotidae. They are found in various habitats across Africa, the Middle East, Asia, and some tropical islands. The family includes greenbuls, brownbuls, leafloves, and bristlebills, with a total of 166 species in 32 genera. African bulbuls are commonly found in rainforests, while Asian bulbuls prefer open areas. They have a diverse distribution and are known for their melodious songs.

Bunting (bird): Buntings, comprising the Emberiza genus, are a group of Old World passerine birds. They are the sole genus in the Emberizidae family, consisting of 45 species. These seed-eating birds have short, cone-shaped bills.

Cardinalidae: The Cardinalidae is a family of New World passerine birds, including cardinals, grosbeaks, and buntings. It also comprises other genera like Piranga and Granatellus. Membership is determined more by molecular work than physical traits. These songbirds vary in size, with stout features and some species having large bills.

Finch: Finches are small to medium-sized birds in the family Fringillidae. They have stout conical bills for eating seeds and nuts and often display colorful plumage. These resident birds are found in various habitats worldwide, except for Australia and the polar regions. The family Fringillidae consists of over 200 species in 50 genera, including canaries, siskins, redpolls, serins, grosbeaks, euphonias, and Hawaiian honeycreepers.

Icterid: Icterids, also known as New World blackbirds, are a family of small to medium-sized, colorful birds found in the Americas. With 108 species in 30 genera, they showcase a wide range of sizes, shapes, behaviors, and colors. Most icterids have black plumage with vibrant accents of yellow, orange, or red. The name originates from the Greek ikteros, meaning "jaundiced ones," and includes New World blackbirds, orioles, bobolinks, meadowlarks, grackles, cowbirds, oropendolas, and caciques.

Lark: Larks are passerine birds found worldwide, with the highest species diversity in Africa. They are known for their ability to live in diverse habitats, including dry regions. The Eurasian skylark is a commonly referred to species when using the term "lark".

Mockingbird: Mockingbirds are New World passerine birds known for mimicking the songs of other birds and sounds of insects and amphibians. They belong to the family Mimidae, consisting of about 17 species in two genera. Some mockingbird species were previously placed in a separate genus called Nesomimus. Interestingly, the mockingbirds do not form a monophyletic lineage, as Melanotis is more closely related to catbirds, while Mimus appears to be closer to thrashers like the sage thrasher.

New World warbler: The New World warblers, or wood-warblers, are a family of small, colorful birds found exclusively in the New World. They belong to the family Parulidae and consist of 120 species. Unlike Old World and Australian warblers, they are not closely related. Most of them live in trees, but some, like the ovenbird and waterthrushes, prefer terrestrial habitats. These birds are mainly insectivores.

Old World flycatcher: Old World flycatchers are small passerine birds that are primarily found in the Old World, with a few exceptions. They are mainly insectivores and catch their prey while flying. The Muscicapidae family consists of 351 species divided into 54 genera.

European robin: The European robin is a small passerine bird belonging to the chat subfamily. It is found across Europe, Western Siberia, and North Africa. In Great Britain and Ireland, it is commonly known as the robin or robin redbreast. The bird is insectivorous and mostly sedentary, except in the far north.

Common nightingale: The common nightingale, also known as the rufous nightingale or nightingale, is a small bird famous for its beautiful and strong song. It was previously classified as a thrush, but is now considered an Old World flycatcher. This species is part of a group of mainly terrestrial birds often called chats.

Old World sparrow: Old World sparrows, also known as true sparrows, are small passerine birds in the family Passeridae. They are distinct from New World sparrows and other similar birds. Many species inhabit cities and nest on buildings, with Eurasian tree sparrows being particularly common. These sparrows primarily eat seeds but also consume small insects. Some species scavenge for food in urban areas and have a varied diet.

House sparrow: The house sparrow is a small bird found worldwide, with males having distinctive black, white, and brown markings. It belongs to the sparrow family Passeridae and is one of about 25 species in the genus Passer. Native to Europe, the Mediterranean Basin, and Asia, it has been introduced to many other regions, making it the most widely distributed wild bird.

Ploceidae: Ploceidae is a family of small passerine birds known as weavers, weaverbirds, weaver finches, or bishops. They build intricately woven nests using vegetation. This family originated in the mid-Miocene and consists of birds native to the Old World, mostly in Africa. Some species have been introduced to other regions.

Starling: Starlings are small to medium-sized passerine birds from the family Sturnidae. They have 128 species divided into 36 genera. Asian species are called mynas, while African species are known as glossy starlings due to their shiny feathers. Starlings are native to Europe, Asia, Africa, northern Australia, and the Pacific islands, but have been introduced to North America, Hawaii, and New Zealand, where they are considered invasive. The most familiar species in Europe and North America is the common starling, while the common myna is prevalent in Asia and the Pacific.

Common myna: The common myna, also known as the Indian myna, is an adaptable bird found in Asia. It belongs to the Sturnidae family and is known for its omnivorous diet. With a strong territorial instinct, it thrives in urban environments as well as open woodlands.

Common starling: The common starling, known as the European starling in North America and the starling in Great Britain and Ireland, is a medium-sized bird with glossy black plumage and a metallic sheen. It is about 20 cm long, has pink legs and a black bill in winter (yellow in summer), and young birds have browner feathers. It is noisy and has a varied song. The common starling is known for its gift of mimicry, mentioned in literature such as the Mabinogion, Pliny the Elder's works, and William Shakespeare's writings.

Sunbird: Sunbirds and spiderhunters are small, colorful passerine birds from the Old World. They have downward-curved bills and many males display vibrant, iridescent feathers. Some species have long tail feathers. They are found in Africa, the Middle East, Asia, and Australia, with the highest diversity in equatorial regions.

Swallow: Swallows are passerine songbirds found worldwide, known for their aerial feeding skills and distinctive appearance. There are around 90 species divided into 19 genera, with the highest diversity in Africa. They are colloquially called "swallow" in Europe, mainly referring to the barn swallow. They can be found on all continents, including Antarctica, and some oceanic islands. While European and North American species migrate long distances, those in West and South Africa are nonmigratory. Swallows are believed to have evolved as hole-nesters in Africa.

Tit (bird): Tits are small passerine birds found mainly in the Northern Hemisphere and Africa. They belong to the family Paridae, which also includes chickadees and titmice. Previously, most of them were classified under the genus Parus.

Thrush (bird): Thrushes are small to medium-sized ground living birds found worldwide. They belong to the passerine bird family Turdidae. They feed on insects, other invertebrates, and fruit. The family was once larger, but biologists reclassified some species as Old World flycatchers. Some unrelated species are named after thrushes due to their resemblance to this bird family.

American robin: The American robin, a migratory bird, is part of the true thrush genus and Turdidae family. It is named after the European robin but is not closely related to it. Known for its reddish-orange breast, the American robin is widespread throughout North America, wintering from southern Canada to central Mexico and along the Pacific coast.

Wren: Wrens are a family of brown passerine birds found mainly in the Americas. There are 88 species divided into 19 genera. The Eurasian wren is the only one occurring in the Old World, where it is commonly called "wren". The name has also been used for unrelated birds in New Zealand and Australia.

Antbird: Antbirds are a diverse family of passerine birds found in Central and South America. With over 230 species, they are known by various names such as antshrikes, antwrens, and fire-eyes. They are not related to wrens, vireos, or shrikes but are closely related to other bird families like antthrushes and tapaculos.

Ovenbird (family): Ovenbirds, belonging to the family Furnariidae, are small suboscine passerine birds found across Mexico and Central to southern South America. With about 315 species and 70 genera, they make up a large family. However, the ovenbird itself, found in North America, is not a furnariid but instead a distantly related member of the wood warbler family, Parulidae.

Tyrant flycatcher: Tyrant flycatchers are a diverse family of passerine birds found in North and South America. With over 400 species, they are the largest bird family in the world. These birds vary in shape, size, and color, with some resembling Old World flycatchers. While they belong to the suborder Tyranni, they do not possess advanced vocal abilities like most songbirds.

Cormorant: Cormorants are a family of about 40 aquatic bird species known as cormorants and shags. The International Ornithologists' Union has established a consensus taxonomy of seven genera within this family. In Britain and Ireland, the great cormorant and the common shag are the only commonly encountered species. The terms "cormorant" and "shag" have been given to other species in the family somewhat randomly.

Darter: Darters, also known as anhingas or snakebirds, are tropical waterbirds in the Anhingidae family. They have a long, snake-like neck and impale fish with their thin beak. There are four species, with one classified as near-threatened. The American darter, also called anhinga or "water turkey," is a common species with a long tail, often hunted for food.

Frigatebird: Frigatebirds are seabirds found in tropical oceans. They have black feathers, long forked tails, and hooked bills. Males have a red pouch they inflate to attract mates. With wingspans up to 2.3 meters, they have the largest wing area to body weight ratio among birds.

Pelican: Pelicans are large water birds with long beaks and throat pouches for catching prey and draining water. They have pale plumage, except for brown and Peruvian pelicans. Before breeding, their bills, pouches, and facial skin become brightly colored.

Sulidae: The Sulidae family consists of gannets and boobies, known as sulids. They are medium-large coastal seabirds that dive for fish and similar prey. Initially, older sources considered all 10 species to be in the same genus, Sula. However, distinctive characteristics in morphology, behavior, and DNA sequences differentiate the gannets (Morus) from the true boobies (Sula). Abbott's booby (Papasula) is a unique lineage that stands apart from both and may be closer to the gannets than to the true boobies.

Honeyguide: Honeyguides are birds in the order Piciformes with a tropical distribution. They are known as indicator birds or honey birds. They primarily reside in Africa and Asia. Honeyguides have a unique interaction with humans as they guide them to bee colonies, allowing themselves to feast on the grubs and beeswax left behind.

Toucan: Toucans are colorful birds in the Ramphastidae family, closely related to American barbets. They are known for their large bills and bright markings. With over 40 species, they belong to five different genera.

Woodpecker: Woodpeckers are birds found worldwide, except in certain regions. They reside in forests, woodlands, deserts, and rocky hillsides. They are part of the Picidae family, which also includes piculets, wrynecks, and sapsuckers. The Gila woodpecker is known for its unique ability to exploit cacti as a food source.

Procellariiformes: Procellariiformes is an order of seabirds consisting of albatrosses, petrels, shearwaters, and storm petrels. They are often referred to as petrels, except for the albatrosses. These seabirds are mainly found in the open ocean and have a global distribution, with a higher diversity in the vicinity of New Zealand.

Albatross: Albatrosses are large seabirds found in the Southern Ocean and North Pacific. They are related to other seabirds in the order Procellariiformes. Albatrosses have long wingspans, with some species reaching up to 3.7 m (12 ft). They are typically grouped into four genera, but the exact number of species is debated. Albatrosses used to occur in the North Atlantic but are now absent, although occasional strays can be found.

Procellariidae: Procellariidae is a family of seabirds including petrels, prions, and shearwaters. They are part of the Procellariiformes order, which also includes albatrosses and storm petrels.

Cockatoo: A cockatoo is a type of parrot belonging to the family Cacatuidae. They are part of the order Psittaciformes and are mainly found in Australasian regions including the Philippines, Indonesia, New Guinea, Solomon Islands, and Australia. There are 21 different species of cockatoos, making up the only family in the superfamily Cacatuoidea.

Parrot: Parrots, also known as psittacines, are tropical and subtropical birds with a strong curved beak, upright stance, and clawed feet. They belong to four families: Psittaculidae, Psittacidae, Cacatuoidea, and Strigopidae. There are about 410 species in 101 genera, with one-third at risk of extinction, making parrots one of the most endangered bird groups. They have a wide distribution, including temperate regions, but are most diverse in South America and Australasia.

Budgerigar: The budgerigar, also known as the common parakeet, is a small, long-tailed parrot that primarily eats seeds. It is the only species in the Melopsittacus genus. Wild budgies are green and yellow with black markings. Captive-bred budgies come in various colors and even have small crests. Juveniles and chicks look similar, but adults can be distinguished by their cere coloring and behavior.

Ara(bird): The Ara genus of macaws includes eight living species and two extinct species. Coined by Bernard Germain de Lacépède in 1799, Ara is part of the Arini tribe and derives its name from the Tupi word for the sound macaws make.

Cassowary: Cassowaries are flightless, ratite birds found in tropical forests of New Guinea, the Aru Islands, and northeastern Australia. They belong to the genus Casuarius and the order Casuariiformes.

Emu: The emu is the largest native bird of Australia and the second-tallest in the world after the ostrich. It is the only surviving member of the genus Dromaius and is endemic to Australia. Its range covers most of the mainland, and subspecies on Tasmania, Kangaroo Island, and King Island went extinct after European settlement in 1788.

Kiwi (bird): Kiwi are flightless birds found only in New Zealand. They belong to the order Apterygiformes, family Apterygidae, and genus Apteryx. Kiwi are the smallest ratites, about the size of a domestic chicken.

Moa: Moa were flightless birds that lived in New Zealand, but became extinct during the Late Pleistocene-Holocene. There were nine species, with the largest reaching 3.6 meters in height and weighing 230 kilograms. The smallest species was similar in size to a turkey. The moa population at the time of Polynesian settlement is estimated to have been between 58,000 and 2.5 million.

Common ostrich: The common ostrich, a flightless bird found in Africa, is one of two surviving species of ostriches. It belongs to the ratite order of birds and is the only member of the Struthio genus. The Somali ostrich is the other species, recently recognized as distinct by BirdLife International.

Rhea (bird): The Rhea, also called ñandu or South American ostrich, is a moderately-sized bird found in South America. It belongs to the order Rheiformes and is closely related to the emu and African ostriches. Rheas are slightly smaller than emus and share similar characteristics.

Tinamou: The Tinamou is a bird species belonging to the Tinamiformes order. It is part of the Tinamidae family, with 46 species found in Mexico, Central America, and South America. They are ground-dwelling birds that prefer hiding or running rather than flying when faced with danger. Tinamous can be found in various habitats, from alpine grasslands to rainforests. The two subfamilies, Nothurinae and Tinaminae, are distinguished by their habitats: steppe/open country and forest, respectively.

Penguin: Penguins are aquatic flightless birds that are highly adapted for life in the ocean. They have dark and white plumage to blend with their surroundings, along with flippers for swimming. Found mostly in the Southern Hemisphere, penguins feed on krill, fish, and squid, catching their prey with their bills and swallowing whole while swimming. They also possess a spiny tongue and strong jaws to grip slippery prey.

Owl: Owls are nocturnal birds of prey with over 200 species. They have an upright stance, a broad head, and sharp talons. Owls are known for their binocular vision, binaural hearing, and feathers adapted for silent flight. Some exceptions to their solitary nature are the diurnal northern hawk-owl and the gregarious burrowing owl.

Eurasian eagle-owl: The Eurasian eagle-owl, also known as Uhu, is a large owl species found in Eurasia. It is one of the biggest owls, with females reaching a length of 75 cm and a wingspan of 188 cm. Their upper parts are mottled with darker blackish and tawny coloration, while the underparts are buff and streaked. The owl has distinctive ear tufts and orange eyes. It is occasionally referred to as just the eagle-owl in Europe.

Barn owl: The barn owl, or common barn owl, is a widespread species of owl found almost everywhere in the world except for polar and desert regions, Asia north of the Himalayas, some Indonesian islands, and some Pacific Islands. It is a member of the Tytonidae family, forming one of the two main lineages of living owls.

Trogon: The trogons and quetzals are birds in the order Trogoniformes, with 46 species in one family. These birds have existed for 49 million years and are believed to be closely related to mousebirds and owls. The name "trogon" comes from Greek and refers to their habit of gnawing holes in trees to make nests.

Resplendent quetzal: The resplendent quetzal is a small bird found in southern Mexico and Central America, specifically in tropical forests. They are a part of the Trogonidae family and have two recognized subspecies. These birds primarily eat fruits from the laurel family but also target insects, lizards, frogs, and snails.

Archaeopteryx: Archaeopteryx, also known as "Urvogel," is a genus of avian dinosaurs. Its name combines the Greek words for "ancient" and "feather" or "wing." For a long time, it was considered the oldest-known bird. However, newer findings have identified older potential avialans such as Anchiornis, Xiaotingia, and Aurornis.

Reptile: Reptiles are tetrapods with cold-blooded metabolism and amniotic development. They include turtles, crocodilians, squamates, and rhynchocephalians. The Reptile Database lists around 12,000 living species. The study of reptiles, along with amphibians, is known as herpetology.

Crocodilia: Crocodilia is an order of mostly large, predatory, semiaquatic reptiles known as crocodilians. They first appeared 94 million years ago in the Late Cretaceous period and are the closest living relatives of birds. Members of the order's total group, the clade Pseudosuchia, appeared about 250 million years ago in the Early Triassic period. The order includes true crocodiles, alligators, caimans, gharials, and false gharials. Crocodilians are the only known survivors of the Archosauria.

Alligator: Alligators, also known as gators, are large reptiles in the Crocodilia order. They belong to the genus Alligator and the family Alligatoridae. The two surviving species are the American alligator and the Chinese alligator. Alligators have been present since the Oligocene epoch, around 37 million years ago.

Caiman: Caimans are small crocodilian reptiles found in Mexico and Central & South America. They have scaly skin and lead a nocturnal lifestyle. The black caiman is the largest species, growing over 4 meters long and weighing more than 1,000 kg. The Cuvier's dwarf caiman is the smallest species, reaching lengths of 1.2 to 1.5 meters. There are six different caiman species in total, and they primarily inhabit marshes, swamps, mangrove rivers, and lakes in the region.

Crocodile: Crocodiles are large reptiles found in tropical regions worldwide and are part of the Crocodilia order, which also includes alligators, caimans, and gharials.

Lizard: Lizards are squamate reptiles found worldwide, excluding Antarctica, and comprise over 7,000 species. Some lizards are closer related to snakes than to other lizards. They vary in size from a few centimeters to the massive Komodo dragon.

Gecko: Geckos are carnivorous lizards, found worldwide in warm climates, except Antarctica. Belonging to the Gekkota infraorder, they vary in size from 1.6 to 60 centimeters.

Gila monster: The Gila monster is a venomous lizard found in the Southwestern United States and northwestern Mexico. It is a slow-moving reptile, measuring up to 56 centimeters long. They are the only venomous lizards native to the United States, while their close relatives, four beaded lizards, are found in Mexico and Guatemala. Although not generally dangerous or a threat to humans, they have a fearsome reputation and are sometimes killed, despite being protected by state law in Arizona.

Komodo dragon: The Komodo dragon is an enormous reptile from the monitor lizard family Varanidae found only in Indonesia. It is the biggest living lizard, reaching up to 3 m (9.8 ft) in length and weighing around 70 kg (150 lb).

Skink: Skinks are a diverse family of lizards, with over 1,500 species in 100 genera. They have smaller legs than typical lizards and inhabit various habitats, excluding arctic and subarctic regions.

Chameleon: Chameleons are a unique group of Old World lizards, with around 200 known species. They are famous for their ability to change colors, ranging from different hues to brightness. While some chameleons primarily change brightness, others display a wide variety of color combinations.

Green iguana: The green iguana, a large lizard belonging to the Iguana genus, is also known as the American iguana. It is primarily arboreal and mostly herbivorous. Found in a wide geographic area from southern Brazil to Mexico, it is commonly referred to as the iguana.

Horned lizard: The horned lizard, also known as the horned lizard, horny toad, or horntoad, is a type of North American lizard. They have horns on their heads, flattened bodies, rounded shapes, and blunt snouts. The horned lizard is part of the Phrynosomatidae family.

Tuatara: Tuatara are unique reptiles found only in New Zealand. They belong to the order Rhynchocephalia, distinguishing them from lizards. The term "tuatara" originates from the Māori language, meaning "peaks on the back."

Snake: Snakes are limbless, carnivorous reptiles with elongated bodies covered in scales. They are ectothermic and have skulls with additional joints, allowing them to swallow prey larger than their heads. Snakes have paired organs appearing one in front of the other and typically possess only one functional lung. Some species still retain vestigial claws and a pelvic girdle. Although legless lizards resemble snakes, they have eyelids and external ears, unlike snakes.

Boidae: The Boidae, also known as boas, are a family of nonvenomous snakes found in Americas, Africa, Europe, and Asia. They include some of the world's largest snakes, such as the South American green anaconda. Boas generally range from medium to large in size, with females typically larger. There are currently 15 genera and 54 species recognized within the family.

Garter snake: The Garter snake is a small to medium-sized snake found in North and Central America. It belongs to the genus Thamnophis in the Colubridae family. These snakes are native to all of the lower 48 United States and most of the Canadian provinces, except for Newfoundland and Labrador. They can be found from west-central Canada to the subarctic plains, as well as from the Maritime Provinces to Florida and across the southern and central United States. Garter snakes also inhabit the arid regions of the southwest, Mexico, Guatemala, and the neotropics, including Costa Rica.

Naja: Naja is a widespread genus of venomous snakes known as cobras. They are recognized as the true cobras and can be found in Africa, Southwest Asia, South Asia, and Southeast Asia. Other snakes like the king cobra and rinkhals are commonly called cobras, but they belong to different genera.

Coral snake: Coral snakes are a diverse group of elapid snakes separated into two main categories: Old World coral snakes and New World coral snakes. The Old World group consists of 16 species in three genera, while the New World group includes over 65 recognized species in two genera. Studies suggest that the oldest lineages originated in Asia. Venomous, New World species rarely cause death, with only two confirmed fatalities in the past century. The genus Micruroides has never caused a medically significant bite.

Mamba: Mambas are highly venomous snakes native to sub-Saharan Africa. There are four recognized species, with three being arboreal and green, and one terrestrial and brown or grey. The black mamba is particularly feared across its range. These snakes are known for their speed and have numerous legends and stories associated with them in Africa.

Sea snake: Sea snakes, also known as coral reef snakes, are elapid snakes that live in marine environments. They are divided into two subfamilies, Hydrophiinae and Laticaudinae. Hydrophiinae includes both marine and terrestrial snakes found in Australasia, while Laticaudinae includes only the sea kraits. There are 69 species of sea snakes in total, belonging to seven different genera.

Agkistrodon piscivorus: The Agkistrodon piscivorus is a venomous snake found in the Southeastern United States. It is a large semi-aquatic viper known for its painful and potentially fatal bite. When threatened, it coils its body, displays its fangs, and may bite. It prefers to inhabit or stay near water, including slow-moving lakes, streams, and marshes. This snake is an adept swimmer and can occasionally be found swimming between barrier islands and the mainland.

Eastern copperhead: The eastern copperhead, or simply copperhead, is a venomous snake native to eastern North America. It belongs to the subfamily Crotalinae within the Viperidae family.

Rattlesnake: Rattlesnakes are venomous vipers that reside in diverse habitats, capturing small animals like birds and rodents.

Adder: Vipera berus, also called common European adder, is a venomous snake found all across Europe and East Asia. It belongs to the Viperidae family and has three known subspecies.

Turtle: Turtles are reptiles with a unique shell formed mainly from their ribs. They can be split into two groups, Pleurodira and Cryptodira, depending on how their heads retract. With about 360 species, including tortoises and terrapins, they inhabit various continents, islands, and oceans. Turtles, like other amniotes, breathe air and typically do not lay eggs underwater, although they often live near water.

Alligator snapping turtle: The Alligator Snapping Turtle is a large and heavy freshwater turtle native to the United States. It is the biggest freshwater turtle in North America and one of the heaviest globally. Although it shares some similarities with the common snapping turtle, they are not closely related. The species name temminckii honors the Dutch zoologist Coenraad Jacob Temminck.

Box turtle: Box turtles are a group of turtle species found in Asia and North America. They have a dome-shaped shell that can be closed tightly for protection. Asian box turtles belong to the Cuora or Pyxidea genus, while North American box turtles belong to the Terrapene genus. These two genera differ in habitat, behavior, and appearance, and are not classified in the same family. Box turtles are popular pets, but their captive care requires complexity, and capturing them can harm wild populations.

Common snapping turtle: The common snapping turtle is a large freshwater turtle found in the Americas. It has a wide range that extends from Canada to Florida. It is one of the few remaining species in its family, Chelydridae. The common snapping turtle is known for its widespread distribution.

Painted turtle: The painted turtle is a widespread native turtle in North America, found from Canada to Mexico and from the Atlantic to the Pacific. It prefers wetlands with long inundation periods and has adapted to withstand freezing temperatures. Belonging to the Chrysemys genus in the Emydidae family, fossils indicate its existence 15 million years ago. Some consider the southern painted turtle as a separate species or subspecies.

Red-eared slider: The red-eared slider is a popular pet turtle known for its invasive nature. It is a semiaquatic turtle belonging to the family Emydidae and is the most commonly traded turtle globally.

Sea turtle: Sea turtles, also known as marine turtles, are reptiles found in oceans. There are seven species: flatback, green, hawksbill, leatherback, loggerhead, Kemp's ridley, and olive ridley. Six of these species are found in U.S. waters and are endangered or threatened. Globally, all species except flatback are considered threatened on the IUCN Red List. Flatback turtles are exclusive to Australia, Papua New Guinea, and Indonesia.

Tortoise: Tortoises are reptiles (Testudinidae) with a protective shell to avoid predation. They have a hard shell, retracting their necks and heads into it for protection.

Galápagos tortoise: The Galápagos tortoise is the largest species of tortoise, with some weighing up to 417 kg. It belongs to the genus Chelonoidis and consists of 15 subspecies. These tortoises are the largest living tortoises and terrestrial ectotherms.

Dinosaur: Dinosaurs are a reptile group that appeared over 200 million years ago and became the main land-dwelling animals after a major extinction event. Birds are considered feathered dinosaurs, evolving from theropods in the Late Jurassic. This makes birds the only surviving dinosaur lineage, while all other dinosaurs are now extinct.

Triceratops: Triceratops is a late Cretaceous dinosaur from western North America, known for its three horns and the frill on its head. It lived until the Cretaceous-Paleogene extinction event, about 66 million years ago. The name Triceratops originates from Greek words meaning 'three-horned face'.

Iguanodon: Iguanodon is a genus of dinosaur that lived during the Late Jurassic and Early Cretaceous periods. It is primarily based on one well-established species called I. bernissartensis. These large herbivores measured around 9-11 meters in length and weighed about 4.5 metric tons. They had distinctive thumb spikes for defense and long, grasping fifth fingers for foraging. The fossils of Iguanodon have been found in Belgium, Germany, England, and Spain, dating back 126-122 million years ago.

Stegosaurus: Stegosaurus is an herbivorous armored dinosaur from the Late Jurassic. It had distinctive upright plates on its back and spikes on its tail. Its fossils have been found in the western United States and Portugal, dating back 155 to 145 million years. Three species are universally recognized. Over 80 individual animals of this genus have been discovered. Stegosaurus coexisted with dinosaurs like Apatosaurus, Diplodocus, Camarasaurus, and may have been preyed upon by Allosaurus.

Apatosaurus: Apatosaurus is a herbivorous dinosaur that lived in North America during the Late Jurassic period. It was first described in 1877 and named A. ajax, with a second species, A. louisae, named in 1916. Apatosaurus fossils are found in Colorado, Oklahoma, New Mexico, Wyoming, and Utah. They measured about 21-23 meters in length and weighed around 16.4-22.4 tons on average. Some specimens were even larger, reaching a length 11-30% greater than average and weighing around 33 tons.

Diplodocus: Diplodocus was a dinosaur genus, a type of sauropod with long necks and tails. Its fossils were discovered in 1877 and the name comes from the Greek words for "double" and "beam," referring to unique double-beamed chevron bones found in its tail.

Allosaurus: Allosaurus is a large carnosaurian theropod dinosaur that lived during the Late Jurassic period. Its unique concave vertebrae gave it the name "different lizard" in Greek. Described in 1877 by Othniel Charles Marsh, Allosaurus is one of the first well-known theropod dinosaurs in history.

Velociraptor: Velociraptor was a small dinosaur genus that lived in Asia during the Late Cretaceous period, around 75 to 71 million years ago. It is known for two recognized species, V. mongoliensis and V. osmolskae. The first species was described in 1924 and its fossils were found in Mongolia's Djadochta Formation. The second species, named in 2008, was identified from skull material in China's Bayan Mandahu Formation.

Tyrannosaurus: The Tyrannosaurus is a large theropod dinosaur that lived in what is now western North America. The most well-known species is Tyrannosaurus rex or T. rex, which is one of the most complete and studied theropods. It had a wide range and lived on an island continent called Laramidia. Fossils of Tyrannosaurus have been found in various rock formations from the Upper Cretaceous period, around 72.7 to 66 million years ago. It was one of the last non-avian dinosaurs before the Cretaceous-Paleogene extinction event.

Pterosaur: Pterosaurs were ancient flying reptiles that lived from the Late Triassic to the end of the Cretaceous period. They were the first vertebrates to evolve powered flight and had wings made of a skin membrane stretching from their ankles to an elongated fourth finger.

Plesiosaur: Plesiosaurs were ancient marine reptiles that lived during the Mesozoic era. They belong to the Sauropterygia group and are now extinct.

Synapsid: Synapsids are a major group of vertebrate animals in the Amniota group, dominating the land during the late Paleozoic and early Mesozoic eras. Unlike other amniotes, they have a single temporal fenestra, an opening low in the skull behind each eye orbit. Synapsids diverged from sauropsids about 318 million years ago, and mammals are the only surviving group in the Cenozoic era.

Dimetrodon: Dimetrodon is a non-mammalian synapsid that lived around 295-272 million years ago. It had a large sail on its back formed by elongated spines and measured 1.7-4.6 m long, weighing 28-250 kg. It had a tall, curved skull with large teeth of different sizes. Fossils have been found in the Southwestern United States, primarily in the Red Beds of Texas and Oklahoma, but also in Germany. Over a dozen species have been named since its discovery in 1878.

Amphibian: Amphibians are a class of vertebrate animals that are ectothermic and have four limbs. They are a diverse group, excluding amniotes, and are mostly found in freshwater, wetland, or terrestrial habitats. They belong to the subclass Lissamphibia, consisting of three orders: frogs, salamanders, and caecilians. Amphibians undergo a life cycle that starts as aquatic larvae called tadpoles, although some species have adapted to skip this stage.

Caecilian: Caecilians are limbless, worm-shaped or snake-shaped amphibians found in the tropics of South and Central America, Africa, and southern Asia. Living hidden in soil or streambeds, caecilians are cryptic and among the least known amphibians. They have small or absent eyes and feed on subterranean creatures. Their cylindrical bodies are often darkly colored, with a bullet-shaped and strong skull. Caecilian heads have unique adaptations like fused cranial and jaw bones, a two-part jaw muscle system, and a chemosensory tentacle. Their slimy skin bears ringlike markings or grooves and may contain scales.

Frog: A frog is a short-bodied, tailless amphibian that belongs to the order Anura. They are carnivorous and widely distributed, with the highest species diversity found in tropical rainforests. Frogs make up 88% of all amphibian species and are one of the top five diverse vertebrate groups. The distinction between frogs and toads is not based on taxonomy or evolutionary history, but is informal.

Hylidae: 'Hylidae' is a family of frogs known as "tree frogs and their allies". Despite their name, hylids encompass various frog species that inhabit not only trees but also terrestrial and semiaquatic environments.

Leptodactylidae: The Leptodactylidae are a diverse family of frogs that likely appeared during the Cretaceous period. They are known as "southern frogs," deriving their name from Greek, meaning slender-toed animals. The family consists of 206 species, divided into 13 genera, predominantly found in Mexico, the Caribbean, Central, and South America. This group includes frogs with various lifestyles, such as terrestrial, burrowing, aquatic, and arboreal, adapting to a wide range of habitats. Notably, taxonomic revisions have resulted in the Eleutherodactylinae subfamily being classified as its own family, called Eleutherodactylidae.

True toad: A true toad is a member of the Bufonidae family in the order Anura. It is the only family where all members are referred to as toads, although some may be called frogs. There are over 35 genera of bufonids, with Bufo being the most famous.

True frog: The true frogs (Ranidae) are a widespread family of frogs, found on all continents except Antarctica. They have the widest global distribution of any frog family, occurring in North and South America, Europe, Africa, and Asia. One species, the Australian wood frog, has even reached the far north of Australia.

American bullfrog: The American bullfrog, also known simply as the bullfrog, is a sizable frog native to eastern North America. It prefers living in large bodies of water like swamps and lakes, but can also adapt to manmade habitats. The male bullfrog is named for its deep bellowing sound during breeding season. It is a large frog and is commonly consumed, particularly in the southern United States where it is abundant.

Salamander: Salamanders are amphibians with lizard-like bodies, slender shapes, blunt snouts, and tails in both larvae and adults. They belong to the order Urodela in the group Caudata, with ten families. They are most diverse in eastern North America, particularly in the Appalachian Mountains, and are also found in the Holarctic and Neotropical realms.

Newt: A newt is a semiaquatic salamander that goes through three life stages: aquatic larva, terrestrial juvenile (eft), and adult. They are found in North America, Europe, North Africa, and Asia. Adult newts have lizard-like bodies and breed in water annually, while living in moist land habitats.

Fish: A fish is an aquatic animal with gills, lacking limbs with digits. This includes various species such as hagfish, lampreys, cartilaginous and bony fish, as well as extinct related groups. Most fish species (95%) are ray-finned and belong to the class Actinopterygii, with teleosts accounting for the majority (99%) of these.

Chondrichthyes: Chondrichthyes, or cartilaginous fish, are a class of jawed fish with skeletons made mostly of cartilage. They differ from bony fish by lacking bones as their main skeletal component. These aquatic vertebrates have paired fins, paired nares, placoid scales, a conus arteriosus in the heart, and do not possess an opecula or swim bladders. Cartilaginous fish are unique among jawed vertebrates within the infraphylum Gnathostomata.

Osteichthyes: Osteichthyes, known as bony fish, are vertebrate animals with skeletons primarily made of bone. They differ from Chondrichthyes, which have cartilage skeletons. Osteichthyes is a highly diverse group with over 28,000 species, making it the largest class of vertebrates today.

Actinopterygii: Actinopterygii, also known as ray-finned fish, is a bony fish class that makes up more than half of all vertebrate species. Their fins are made of webbing supported by thin bony spines called lepidotrichia, different from the fleshy lobed fins of other fish. These fan-like fins have the ability to change shape and wetted area, providing better movement efficiency. The fin rays are directly attached to the skeletal elements, called radials, which connect the fins to the internal skeleton.

Sarcopterygii: Sarcopterygii, also known as lobe-finned fish or sarcopterygians, have muscular limb buds (lobes) within their fins, supported by articulated appendicular skeletons. They are distinct from the other group of bony fish, Actinopterygii, which have fins supported by skin-covered bony spines.

Coelacanth: Coelacanths are an ancient group of lobe-finned fish in the class Actinistia. They are closely related to lungfish and tetrapods, rather than ray-finned fish.

Lungfish: Lungfish are unique freshwater vertebrates with the ability to breathe air and retain ancestral traits within Osteichthyes and Sarcopterygii. They are the closest living relatives of tetrapods and have tooth plates in their mouths to crush hard shelled organisms.

Batoidea: Batoidea is a superorder of rays, a type of cartilaginous fish. They belong to the subclass Elasmobranchii along with their close relatives, the sharks. With over 600 species in 26 families, rays are the largest group of cartilaginous fishes. Their key features include flattened bodies, pectoral fins fused to the head, and gill slits located on their underside.

Manta ray: Manta rays are large rays in the genus Mobula, with M. birostris reaching 7 m (23 ft) wide and M. alfredi reaching 5.5 m (18 ft) wide. They have triangular pectoral fins, horn-shaped cephalic fins, and forward-facing mouths. Manta rays, classified among Myliobatiformes in the family Myliobatidae, possess the largest brains and brain to body ratio among fish and can pass the mirror test.

Electric ray: Electric rays are cartilaginous fish with enlarged pectoral fins. They belong to the order Torpediniformes and have the ability to produce an electric discharge. This discharge can range from 8 to 220 volts and is used for stunning prey and self-defense. There are a total of 69 species of electric rays, spread across four families.

Sawfish: Sawfish, also called carpenter sharks, are large rays with a distinct long, narrow nose lined with sharp, saw-like teeth. They can grow up to 7-7.6 m (23-25 ft) in length. Found globally in tropical and subtropical areas, they inhabit various water bodies including seas, estuaries, and freshwater rivers. Sadly, all sawfish species are currently endangered.

Skate (fish): Skate (fish) are cartilaginous fish in the Rajidae family of the Batoidea superorder. They include more than 150 described species across 17 genera. Formerly considered subfamilies, softnose and pygmy skates are now recognized as distinct families. The term "skate" can also extend to the entire Rajiformes order.

Stingray: Stingrays are cartilaginous fish related to sharks. They belong to the suborder Myliobatoidei and consist of eight families. There are approximately 220 known stingray species categorized into 29 genera.

Chimaera: Chimaeras, or ghost sharks, are cartilaginous fish (Chimaeriformes) also called rat fish, spookfish, or rabbit fish. They should not be confused with other species named rattails, Opisthoproctidae, or Siganidae.

Shark: Sharks are elasmobranch fish with a cartilaginous skeleton, gill slits on the head, and separate pectoral fins. They belong to the Selachimorpha group and are closely related to the Batoidea. Extinct Chondrichthyes with shark-like traits are sometimes included. Shark-like species appeared in the Devonian Period, while confirmed modern sharks date back to the Early Jurassic, about 200 million years ago. True shark records might go back even further.

Nurse shark: The nurse shark is a type of fish in the Ginglymostomatidae family. It is globally assessed as Vulnerable and near threatened in the western Atlantic Ocean due to threats in South America, Central America, and the Caribbean. It is targeted in certain fisheries and considered by-catch in others.

Whale shark: The whale shark is the largest known fish and a filter-feeding shark. It can reach lengths of up to 18.8 m (61.7 ft) and is the most massive non-mammalian animal in the world. It is the only member of its genus and family, belonging to a subclass of cartilaginous fish called Elasmobranchii. Previously classified differently, the whale shark now holds its own scientific classification.

Great white shark: The great white shark, also known as the white shark, is a large mackerel shark found in coastal waters of major oceans. It is the only surviving species of its genus. The largest female specimen measures about 5.83 m (19.1 ft) and weighs around 2,000 kg (4,410 lb) at maturity. They have a lifespan of up to 70 years and take over two decades to reach sexual maturity. Great white sharks can swim at speeds of 25 km/h (16 mph) and dive to depths of 1,200 m (3,900 ft).

Hammerhead shark: The hammerhead shark is a unique type of shark with a flattened and extended head called a cephalofoil. Its eyes are situated on either end of the T-shaped structure, with a small mouth in the center. Most hammerhead species belong to the genus Sphyrna, while the winghead shark is in its own genus, Eusphyra. The cephalofoil serves various purposes, such as sensory reception, maneuvering, and manipulating prey. It also provides the shark with excellent binocular vision and depth perception.

Tiger shark: The tiger shark is a large, ground-dwelling shark found in tropical and temperate waters. It is the only member of its genus and family. Female tiger sharks can grow over 5m in length. They are known for their dark stripes resembling a tiger's pattern, which fade as they mature.

Sturgeon: Sturgeon is a family of fish (Acipenseridae) comprising 28 species. They are descended from acipenseriform fish and have existed for over 174 million years. Sturgeons, along with paddlefish, belong to the Acipenseriformes group. The family includes the genera Acipenser, Huso, Scaphirhynchus, and Pseudoscaphirhynchus. Some sturgeon species are possibly extinct in the wild. They inhabit rivers, lakes, and coastlines in Eurasia, North America, and Africa.

Eel: Eels are fish that belong to the order Anguilliformes, consisting of about 1000 species. They undergo significant development, starting as larvae and growing into predators as adults.

Flying fish: Flying fish, scientifically known as Exocoetidae, are marine ray-finned fish that belong to the Beloniformes order. They are also referred to as flying cod. With around 64 species in seven genera, flying fish possess long wing-like fins that allow them to glide above the water's surface for significant distances. While they cannot truly fly like birds, they can propel themselves out of the water to evade predators like swordfish, mackerel, tuna, and marlin. However, this flight behavior also makes them vulnerable to attacks from birds such as frigate birds.

Characiformes: Characiformes is an order of fish that includes characins and related species. It consists of 18 recognized families with over 2000 different species, including famous fish like piranhas and tetras.

Characidae: The Characidae, also known as characids or characins, is a family of freshwater fish found in subtropical and tropical regions. They belong to the order Characiformes and are considered a predominantly monophyletic group. Tetras, including Hemigrammus and Hyphessobrycon, are some of the fish that are part of this family. Characidae species are both food sources and popular choices for aquariums.

Piranha: A piranha is a freshwater fish found in South American rivers, lakes, and reservoirs. It belongs to the family Serrasalmidae and is known for its predatory habits, eating both fish and plant material, making it omnivorous.

Anchovy: Anchovy fish are small forage fish from the Engraulidae family. They are commonly found in marine waters but can also live in brackish or fresh water in South America.

Herring: Herring are small, oily fish from the Clupeidae family, commonly used as forage food.

Ilish: The ilish, also called ilishi or hilsa, is a fish species closely related to herring. It is highly valued for its taste and is widely consumed in the Indian subcontinent. It holds the status of being the national fish of Bangladesh and the state fish of West Bengal.

Sardine: Sardines are small, oily fish in the herring family. The term 'sardine' originated in the 15th century and might relate to the Italian island of Sardinia, where sardines were once plentiful.

Sprat: Sprats are small, oily forage fish found in the genus Sprattus. They belong to the Clupeidae family and are often grouped with other similar small forage fish. Sprats are known for their high activity levels and travel in large schools with other fish. They swim constantly throughout the day.

Cypriniformes: Cypriniformes is an order of ray-finned fish, including carps, minnows, loaches, and relatives. It belongs to the Superorder Ostariophysi and contains 11-12 families, with over 400 genera and 4,250 species. They are highly diverse in southeastern Asia and absent from Australia and South America. The bigmouth buffalo holds the record for the longest-lived cypriniform fish at 112 years old.

Cyprinidae: Cyprinidae, also known as the carp or minnow family, is the largest and most diverse family of freshwater fish. It includes carps, true minnows, barbs, barbels, and others. With about 3,000 species, it is the largest vertebrate animal family. However, only 1,270 of these species still exist today, divided into approximately 200 valid genera. Cyprinids vary in size from 12 mm to the giant 3 m long barb. They represent more than two-thirds of the Cypriniformes order. The family name is derived from the Greek word kyprînos.

Carp: Carp, a group of freshwater fish from the family Cyprinidae, are native to Eurasia and valued for food and ornamental purposes in the Old World. However, they are considered invasive pests and often considered worthless trash fish in Africa, Australia, and most of the United States.

Goldfish: The goldfish is a popular freshwater pet, commonly kept in indoor aquariums. It belongs to the family Cyprinidae and order Cypriniformes. Unfortunately, released goldfish have become invasive in some parts of North America.

Koi: Koi, or nishikigoi, are colorful carp kept in outdoor ponds for decoration. They may be classified as a separate species in the future due to their distinction from the common carp.

Cyprinodontiformes: Cyprinodontiformes is an order of small, mostly freshwater ray-finned fish. It includes popular aquarium fish like killifish and live-bearers. They are closely related to Atheriniformes and sometimes grouped together. They are known as toothcarps, although they are not true carps and belong to the Acanthopterygii superorder, not Ostariophysi.

Guppy: The guppy, also known as the millionfish or rainbow fish, is a popular freshwater aquarium species. It is widely distributed and highly adaptable to different environments. Guppies are live-bearing and originate from northeast South America but have been introduced globally. Male guppies have ornamental fins and feed on algae and insect larvae. They are used as a model organism in ecology, evolution, and behavioral studies.

Northern pike: The northern pike is a carnivorous fish found in salty and fresh waters of the Northern Hemisphere. It belongs to the Esox genus and is known as a pike in Great Britain, Ireland, Eastern Europe, Canada, and the U.S.

Alaska pollock: The Alaska pollock, also known as walleye pollock, is a marine fish species belonging to the cod genus Gadus and family Gadidae.

Cod: Cod is a type of demersal fish belonging to the family Gadidae. It is used to refer to various fish species, but not all species in the Gadus genus are called cod.

Haddock: The haddock is a saltwater fish from the true cod family. It is found in the North Atlantic Ocean and is important for fisheries. It is marketed fresh, frozen, and smoked, including varieties like Finnan haddie and Arbroath smokie.

Stickleback: The sticklebacks are ray-finned fishes found in various water types across the Holarctic region. Initially believed to be related to pipefish and seahorses, recent studies suggest a stronger connection to eelpouts and sculpins.

Milkfish: The milkfish is a species in the Chanidae family and is the only living member. It originated during the Cretaceous period, and there are five extinct genera related to it. The term 'milkfish' comes from the Greek word khanos.

Electric eel: Electric eels, part of the Electrophorus genus, are neotropical freshwater fish found in South America. They possess a unique ability to generate electricity, delivering shocks of up to 860 volts, which they use to stun their prey. The study of their electrical capabilities since 1775 has played a significant role in the invention of the electric battery in 1800.

Oarfish: The oarfish are elongated fish found in oceans, ranging from temperate to tropical areas. They belong to the Regalecidae family and include three species in two genera. The giant oarfish holds the record for being the longest bony fish, reaching lengths of up to 11 meters (36 feet).

Anglerfish: The Anglerfish is a type of bony fish belonging to the Lophiiformes order. They have a unique way of hunting using a luminescent fin ray that acts as a lure. This light is generated by symbiotic bacteria acquired from seawater.

Mullet (fish): The mullet (fish) is a family of ray-finned fish found worldwide in coastal waters, both temperate and tropical, with some species even inhabiting fresh water. They have been a significant food source in Mediterranean Europe since ancient Roman times. The Mugilidae family consists of approximately 78 species across 20 genera.

Ophidiiformes: Ophidiiformes is an order of slender, small-headed ray-finned fish including cusk-eels, pearlfishes, and viviparous brotulas. They have smooth or no scales, a long dorsal fin, and an anal fin merging into the caudal fin. Found in tropical and subtropical regions, they inhabit freshwater, marine, and abyssal habitats. Ophidiiformes display diverse feeding methods, from parasitism to egg-laying or viviparous reproduction.

Galaxiidae: The Galaxiidae are a family of small freshwater fish mainly found in Southern Australia and New Zealand, but are also present in South Africa, southern South America, Lord Howe Island, New Caledonia, and the Falkland Islands. The common galaxias, a galaxiid species, is widely distributed in the Southern Hemisphere. These coolwater species thrive in temperate latitudes, with some adapted to subtropical habitats. Many Galaxiidae species specialize in cold, high-altitude upland rivers, streams, and lakes.

Smelt (fish): Smelt fish are small members of the Osmeridae family found in North Atlantic, North Pacific oceans, and various water bodies in Europe, North America, and Northeast Asia. They are also referred to as freshwater or typical smelts, distinguishing them from other related fish families.

Arapaima: The Arapaima is a large freshwater fish native to the Amazon and Essequibo basins in South America. They can reach lengths of up to 3 meters (9.8 feet) and are important as a food source. Overfishing and habitat loss have led to a decline in their native range. Arapaima have been introduced to other tropical regions, where they are considered invasive species. They can escape from aquaculture ponds, as seen in Kerala, India in 2018. The Portuguese name "pirarucu" translates to "red fish" in the Tupi language.

Perciformes: Perciformes, known as Acanthopteri, are ray-finned fish in the Percomorpha clade. They are commonly called perch-like fish. This group includes popular species like perch, darters, sea bass, and groupers.

Barracuda: The barracuda is a large predatory fish known for its fierce appearance and behavior. It is found in tropical and subtropical oceans worldwide, near coral reefs and sea grasses. Barracudas are targeted by sport-fishing enthusiasts.

Marlin: Marlins are fish belonging to the Istiophoridae family, with approximately 10 species.

Swordfish: The swordfish, also known as broadbills, is a large predatory fish with a long, pointed bill. They are elusive sport fish found in tropical and temperate oceans. Swordfish are round-bodied and lose their teeth and scales as adults. They can reach a length of 3 meters and weigh up to 650 kg.

Cichlid: Cichlids are fish from the family Cichlidae in the order Cichliformes. They first appeared in Tanzania about 46-45 million years ago. Cichlids are diverse and widely dispersed, with at least 1,650 scientifically described species. However, the actual number of species remains unknown, with estimates between 2,000 and 3,000. They are closely related to the convict blenny and are classified in the Cichliformes along with it.

Tilapia: Tilapia is a type of cichlid fish, consisting of about a hundred species. They are primarily found in freshwater habitats like streams, ponds, rivers, and lakes, occasionally in brackish water. These fish have been historically significant in African artisanal fishing and are increasingly important in aquaculture and aquaponics. While they can become invasive in warm-water habitats such as Australia, they cannot survive in cold water in temperate climates.

Goby: A goby is a type of fish with a large head and tapered body. They can be found in marine, brackish, and freshwater environments.

Siamese fighting fish: The Siamese fighting fish, also known as betta, is a popular freshwater fish native to Southeast Asia. It belongs to the Betta genus and is highly valued as a pet due to its vibrant colors and easy care requirements.

Mahi-mahi: The mahi-mahi, also known as dorado or dolphin, is a surface-dwelling fish found in temperate, tropical, and subtropical waters worldwide. It belongs to the Coryphaenidae family and is commonly found in the Gulf of Mexico, Costa Rica, Hawaii, and the Indian Ocean.

Perch: Perch is a type of freshwater fish belonging to the Perca genus of the Percidae family. They are part of the large order Perciformes. The name "perch" originates from the European perch, which is the type species of this genus.

Remora: The remora, also known as a suckerfish, is a type of fish with a unique oval-shaped dorsal fin that acts as a suction cup. This allows them to attach themselves firmly to larger marine animals. They range in size from 30 to 110 cm and can increase or release suction by sliding backward or swimming forward. Remoras have been observed attaching to small boats and even divers. They swim using a sinuous, or curved, motion.

Mackerel: Mackerel is a type of pelagic fish from the Scombridae family. It encompasses various species and can be found in temperate and tropical seas. These fish typically inhabit coastal areas or live offshore in the oceanic environment.

Tuna: Tuna is a saltwater fish belonging to the Thunnini tribe in the mackerel family. There are 15 species across five genera, with sizes ranging from the bullet tuna to the Atlantic bluefin tuna. The bluefin tuna can reach lengths of 2 meters (6.6 feet) and has an average lifespan of 50 years.

Serranidae: Serranidae is a large fish family that belongs to the order Perciformes. It consists of around 450 species in 65 genera, including sea basses and groupers. While many species are small, the giant grouper stands out as one of the world's largest bony fishes, reaching lengths of 2.7 m and weighing 400 kg. These fish primarily inhabit tropical and subtropical seas across the globe.

European seabass: The European seabass, also known as the European bass, is primarily an ocean-going fish found in the waters off Europe's western and southern coasts and Africa's northern coasts. It is also found in shallow coastal waters and river mouths during the summer and late autumn. It belongs to the Moronidae family, commonly known as temperate basses.

Grouper: Groupers are a type of fish found in the Epinephelinae subfamily of the Serranidae family. They belong to the Perciformes order.

Wrasse: Wrasse is a diverse family of marine fish known for their vibrant colors. With over 600 species in 81 genera, they come in different sizes, although most are small, with the largest reaching 2.5 m. They are carnivorous and feed on various small invertebrates. Some wrasses trail larger fish to scavenge disturbed prey. Certain species of wrasses seek shelter among the tentacles of coral.

Flatfish: Flatfish are ray-finned demersal fish found in the order Pleuronectiformes. They belong to the Heterosomata, sometimes considered a suborder of Perciformes. These fish have both eyes located on one side of their head, with one eye typically migrating around the head during development. Depending on the species, some face their left side upward, some face their right side upward, while others can face either side upward.

Flounder: Flounders are flatfish found worldwide, inhabiting ocean bottoms and occasionally estuaries.

Halibut: Halibut refers to three types of flatfish in the genera Hippoglossus and Reinhardtius. They belong to the family of right-eye flounders. This term is also occasionally used to describe other species of large flatfish in certain areas.

Plaice: Plaice is a type of flatfish that includes four species: European, American, Alaskan, and scale-eye plaice.

Turbot: Turbot is a large flatfish found in the Northeast Atlantic, Baltic Sea, and Mediterranean Sea. It is a demersal fish and a significant food source. In the Black Sea, it is known as the Black Sea turbot. The Northwest Atlantic has a different species called the Greenland halibut or Greenland turbot, which was involved in the "Turbot War" between Canada and Spain.

Bichir: Bichir is an archaic ray-finned fish belonging to the family Polypteridae, which is the sole family in the order Polypteriformes.

Salmonidae: Salmonidae is the only family in the Salmoniformes order, comprising over 200 species of coldwater fish known as "salmonids" or "salmonoids". These mid-level predators include salmon, trout, char, graylings, and others. They inhabit subarctic and cool temperate waters in the Northern Hemisphere. The family and order names are derived from the Latin name of the Atlantic salmon, which is also included in this family.

Salmon: Salmon is a commercially significant fish found in the North Atlantic and North Pacific. It belongs to the Salmonidae family, which includes trout, char, grayling, and other coldwater fish. These species are native to river tributaries and cooler temperate regions, with some populations in Central Asia.

Trout: Trout refers to various carnivorous freshwater fish species in the genera Oncorhynchus, Salmo, and Salvelinus. They are part of the Salmonidae family and Salmoninae subfamily. The term trout is also used for non-salmonid fish with a similar shape, like the spotted seatrout/speckled trout.

Scorpaeniformes: Scorpaeniformes is a diverse order of ray-finned fish known as lionfishes and sculpins, also called Scleroparei. It is among the top five largest orders of bony fishes, containing over 1,320 species.

Catfish: Catfish are diverse ray-finned fish known for their whisker-like barbels. They vary in size from large species like Mekong giant catfish, wels catfish, and piraíba to tiny parasitic species called candiru. Catfish can be detritivores and some are armored or naked. They belong to the Siluriformes order and have commercial and aquarium significance. They have diverse behaviors, with some being nocturnal and others crepuscular or diurnal.

Loricariidae: Loricariidae is the largest catfish family, with over 680 species and 92 genera. These fish are found in freshwater habitats of Costa Rica, Panama, and South America. They have bony plates covering their bodies and suckermouths. Some species, like Hypostomus plecostomus, are popular as aquarium fish and commonly known as "plecos".

Seahorse: Seahorses are small marine fish with a horse-like head and neck. They have segmented bony armor, an upright posture, and a curled prehensile tail. The name "Hippocampus" comes from the Greek words for "horse" and "sea monster." Seahorses, along with pipefishes and seadragons, belong to the family Syngnathidae. They are comprised of 46 different species.

Ocean sunfish: The ocean sunfish, also known as the common mola, is a large bony fish found in tropical and temperate waters worldwide. It is one of the largest bony fish, with adults weighing between 247 and 1,000 kg. The species belongs to the Mola genus in the Molidae family. The ocean sunfish is characterized by its flattened laterally body, resembling a fish head without a tail. When their dorsal and ventral fins are extended, they can be as tall as they are long.

Tetraodontidae: Tetraodontidae, also known as pufferfish, are primarily marine and estuarine fish. They belong to the order Tetraodontiformes and share similarities with porcupinefish. These unique creatures have various names such as blowfish, balloonfish, and globefish. Their scientific name refers to their four large teeth fused for crushing hard crustaceans and mollusks.

Placodermi: Placodermi is an armored class of prehistoric fish found in fossils. They lived during the Silurian and Devonian periods. With articulated plates on their head and thorax, their body was either scaled or naked. Placoderms were one of the first jawed fish, believed to have evolved jaws from gill arches.

Acanthodii: Acanthodii, an extinct class of fish, are considered to be a predecessor to living sharks, rays, and chimaeras. They possess a combination of features found in both bony fish and cartilaginous fish. Their body shape resembles that of modern sharks, but their skin is covered in small rhomboid platelets, similar to the scales of other fish.

Agnatha: Agnatha is a group of jawless fish in the phylum Chordata, including living (cyclostomes) and extinct species. Cyclostomes, the most recent members, are closely related to jawed vertebrates known as gnathostomes.

Hagfish: Hagfish are eel-shaped jawless fish found in the oceans. They have a skull but no vertebral column, though they possess rudimentary vertebrae. Hagfish are marine predators and scavengers that release large amounts of slime to defend against predators.

Lamprey: Lampreys are an ancient type of jawless fish with a toothed, sucking mouth. They belong to the order Petromyzontiformes. The name "lamprey" may come from Latin lampetra, possibly meaning "stone licker". They are often referred to as lamprey in both singular and plural form.

Ostracoderm: Ostracoderms were armored jawless fish that existed during the Paleozoic Era. Although not commonly used in classifications today because it does not represent a single evolutionary lineage, the term is still informally used to group together these ancient fishes.

Ostracod: Ostracods, also called seed shrimp, are small crustaceans belonging to the class Crustacea. They are diverse, with around 33,000 identified species grouped into 7 orders. Ostracods typically measure about 1 mm, but can range from 0.2 to 30 mm in size. Their bodies are flattened and protected by a bivalve-like shell made of chitin and calcium carbonate. Some species lack calcium carbonate. Ostracods vary in diet, with some being carnivores, herbivores, scavengers, or filter feeders, but most are deposit feeders.

Malacostraca: Malacostraca is the second largest class of pancrustaceans, with about 40,000 species divided into 16 orders. Its members, malacostracans, include crabs, lobsters, shrimp, and more. They are found in marine, freshwater, and terrestrial habitats. Malacostracans have a common body plan with 20 segments and are divided into head, thorax, and abdomen.

Woodlouse: A woodlouse is a crustacean in the suborder Oniscidea. They are called woodlice because they are commonly found in old wood. Despite their name, woodlice are not parasitic insects.

Krill: Krill are small crustaceans found in oceans worldwide. The name comes from a Norwegian word meaning "small fry of fish," often associated with certain fish species.

Decapoda: Decapoda is an order of crustaceans that includes crabs, lobsters, crayfish, shrimp, and prawns. They are mainly scavengers. The order has about 15,000 living species and 3,300 fossil species, with crabs being the most abundant. Shrimp, hermit crabs, porcelain crabs, and squat lobsters are also part of this diverse group. Their existence dates back to the Devonian period.

Crab: Crabs are crustaceans with a short "tail" hidden under the thorax. They inhabit oceans, freshwater, and land, are covered by a thick exoskeleton, and possess a single pair of pincers on each arm. Crabs emerged in the Jurassic Period.

Astacus astacus: Astacus astacus, also known as the European crayfish or noble crayfish, is the most prevalent crayfish species in Europe. It thrives in unpolluted freshwater environments and can be found in streams, rivers, and lakes across Central and Eastern Europe, as well as Scandinavia and Finland. The males can reach a length of 16 cm, while the females grow up to 12 cm. Additionally, the European crayfish holds cultural significance as a traditional food source.

Lobster: Lobsters are marine crustaceans with long bodies and muscular tails. They live in crevices or burrows on the sea floor and have three pairs of legs with claws, the first pair being the largest. Valued as seafood, lobsters are economically significant and highly profitable commodities in coastal areas.

Shrimp: A shrimp is an elongated crustacean primarily known for its swimming ability, typically belonging to the Caridea or Dendrobranchiata groups of the decapod order. However, other crustaceans are also referred to as "shrimp."

Arachnid: Arachnids are joint-legged arthropods in the class Arachnida. They belong to the subphylum Chelicerata and include spiders, scorpions, ticks, mites, pseudoscorpions, harvestmen, camel spiders, whip spiders, and vinegaroons.

Mite: Mites are small arachnids belonging to two main orders: Acariformes and Parasitiformes. They have a simple, unsegmented body and are usually less than 1 mm in length. Mites can be found in various habitats, including water, soil, plants, and as parasites or predators. Some mites, like Varroa and scabies mites, cause harm to honey bees and humans respectively. While most mites are harmless, a few can cause allergies or transmit diseases.

Pseudoscorpion: Pseudoscorpions, or false scorpions, are small arachnids resembling scorpions. They belong to the order Pseudoscorpiones, also known as Pseudoscorpionida or Chelonethida.

Tick: Ticks are small parasitic arachnids that feed on the blood of mammals, birds, reptiles, and amphibians. They are about 3 to 5 mm in length and are found worldwide, particularly in warm and humid regions. The oldest known tick fossils date back to around 100 million years ago.

Scorpion: Scorpions are arachnids with eight legs, distinctive pincers, and a curved tail ending in a stinger. They have existed for 435 million years and inhabit various environments, except Antarctica. With over 2,500 species, scorpion taxonomy is being updated based on modern genetic research.

Spider: Spiders are arthropods with eight limbs, fangs that inject venom, and silk-producing spinnerets. They are the largest order of arachnids and can be found worldwide, except Antarctica. There are over 51,000 recorded spider species, but scientists debate about their classification.

Tarantula: Tarantulas are large, hairy spiders belonging to the family Theraphosidae. Over 1,100 species and 166 genera have been identified. The term "tarantula" is commonly used for these spiders, although other similar spiders are also referred to as tarantulas. Some tarantulas are popular in the exotic pet trade. Certain species have urticating hairs that can cause skin irritation and even eye damage.

Insect: Insects, part of class Insecta, are the largest group in the phylum Arthropoda. They have a chitinous exoskeleton, three-part body, three pairs of jointed legs, compound eyes, and a pair of antennae. Insects are incredibly diverse, with over a million described species, making up more than half of all animal species.

Pterygota: The Pterygota are a group of insects known for their wings. This subclass includes both winged insects and those that have lost their ability to fly.

Earwig: Earwigs are insects belonging to the order Dermaptera with about 2,000 species in 12 families. They have characteristic forcep-like pincers on their abdomen called cerci and membranous wings folded underneath rarely used forewings. Some groups are parasites on mammals without pincers. Earwigs can be found on all continents except Antarctica.

Flea: Fleas are small flightless insects that live as external parasites on mammals and birds, feeding on their blood. With around 2,500 species, adult fleas are brown, about 3 millimeters long, and have flattened bodies, allowing them to move through fur or feathers. They lack wings but possess hind legs specialized for jumping and claws to prevent dislodgement. Flea larvae are limbless, worm-like creatures that feed on organic debris found on their hosts' skin.

Louse: A louse is a wingless parasite insect belonging to the Phthiraptera clade, which includes around 5,000 species. Phthiraptera is classified as an order, infraorder, or parvorder depending on recent studies in phylogenetics.

Body louse: The body louse is a type of parasite that lives on human beings and feeds on their blood. It is one of three lice species that infest humans, along with the head louse and pubic louse.

Mantis: Mantis is an insect order (Mantodea) with over 2,400 species in 33 families and 460 genera. They are found worldwide in different habitats. Mantises have triangular heads with bulging eyes on flexible necks and elongated bodies. Some may have wings. All species have enlarged forelegs for catching prey. They are known for their stationary pose with folded forearms, giving rise to their name "praying mantis."

Phasmatodea: The Phasmatodea, also known as stick insects or walkingsticks, are an order of insects. They are named after their resemblance to vegetation, and their natural camouflage helps them avoid predators. Some species have startle displays, spines, or toxic secretions for additional defense. Certain stick insect genera have the world's longest insects.

Beetle: Beetles are insects belonging to the order Coleoptera. They have hardened front wings called elytra, which separate them from most other insects. With approximately 400,000 known species, beetles make up the largest order of insects, accounting for almost 40% of described insect species and 25% of all animal species. They are found in almost all habitats apart from the sea and polar regions. Beetles play various roles in their ecosystems, including feeding on plants, breaking down animal and plant debris, and consuming other invertebrates. While some species are destructive agricultural pests, others like Coccinellidae, commonly known as ladybugs, eat insects that harm crops by sucking plant juices.

Coccinellidae: Coccinellidae, commonly known as ladybugs or ladybirds, are small beetles found worldwide. They have oval bodies and domed backs with flat undersides. With over 6,000 species, they display various aposematic colors and patterns, such as red with black spots, warning predators of their unpalatable taste. Entomologists use the terms ladybird beetles or lady beetles to distinguish them from true bugs.

Dung beetle: Dung beetles are insects that consume feces and have the ability to bury dung heaps weighing 250 times their own body mass within a single night.

Firefly: Fireflies, or Lampyridae beetles, are a family of soft-bodied insects that emit light to attract mates during twilight. With over 2,000 species, their light production originated as a warning signal in larvae and evolved into a mating signal in adults. Some female fireflies even mimic the flash pattern of other species to trap males as prey.

Weevil: Weevils are small beetles with elongated snouts, known for being herbivorous. There are approximately 97,000 known species of weevils, most of which belong to the Curculionidae family. Bark beetles are also considered a subfamily of weevils. Other beetles, like the biscuit weevil, are not closely related but share the name "weevil".

Cockroach: Cockroaches, insects of the order Blattodea, include about 30 species that often inhabit human surroundings, being renowned pests.

Termite: Termites are eusocial insects that consume decaying plant material like wood, leaves, and soil humus. They have moniliform antennae and a soft-bodied worker caste, often mistaken for "white ants". Despite the name, they are not closely related to ants. There are currently 2,972 known termite species, with 2,105 belonging to the Termitidae family.

Fly: Flies are insects (order Diptera) with two wings. They use their hindwings, called halteres, as high-speed sensors for rotational movement, enabling them to perform advanced aerobatics. This large order contains approximately 1 million species, including horse-flies, crane flies, hoverflies, and mosquitoes.

Drosophila melanogaster: Drosophila melanogaster is a fly species known as the fruit fly or lesser fruit fly. It is also called the "vinegar fly," "pomace fly," or "banana fly." These flies are attracted to rotting fruit and fermenting beverages and can be found in orchards, kitchens, and pubs. They belong to the Drosophilidae family.

Black fly: Black flies, also known as blackflies, are insects belonging to the family Simuliidae. They are related to other fly families such as Ceratopogonidae, Chironomidae, and Thaumaleidae. There are over 2,200 formally named species of black flies, with 15 being extinct. They are divided into two subfamilies: Parasimuliinae and Simuliinae. The genus Simulium accounts for over 1,800 of the species.

Botfly: Botflies, or Oestridae, are parasitic flies that infest mammals internally. The larvae of these flies grow within the host's flesh or gut. While Dermatobia hominis commonly parasitizes humans, other fly species also cause myiasis in humans.

Crane fly: A crane fly is a type of insect belonging to the superfamily Tipuloidea, which includes several living families such as Cylindrotomidae, Limoniidae, Pediciidae, and Tipulidae. It also includes some extinct families. Winter crane flies, from the family Trichoceridae, are distinct from typical crane flies and are placed as their sister group within Tipulomorpha.

Calliphoridae: Calliphoridae is a family of insects in the order Diptera, with nearly 1,900 species. The larvae, called gentles, are commonly used as fishing bait. The family is polyphyletic, and there are ongoing debates about how to classify its members, some of which are sometimes considered their own families.

Tabanidae: Tabanidae is a family of true flies in the order Diptera, commonly known as horse-flies and deer flies. They are large and agile in flight, with only female horseflies biting land vertebrates for blood. They are active during the day, avoiding dark areas and are not active at night. These flies can be found worldwide, except on certain islands and polar regions. They are sometimes called gadflies, along with botflies.

Housefly: The housefly, a common fly found in houses worldwide, is believed to have originated in the Middle East. It is gray to black, with hairy bodies, four dark lines on the thorax, and red eyes. The female has slightly larger eyes than the male.

Mosquito: Mosquitoes are a family of small flies with about 3,600 species. They have a segmented body, one pair of wings, three pairs of long legs, and elongated mouthparts for piercing and sucking. They drink nectar from flowers but some female mosquitoes also feed on blood. Mosquitoes are considered micropredators, as they parasitize larger animals by consuming their blood. They are also known as disease vectors, carrying parasites and pathogens from one host to another.

Tsetse fly: Tsetse flies are large biting flies found in tropical Africa. They belong to the genus Glossina and are known for their role in transmitting diseases called trypanosomiasis. These flies are obligate parasites that feed on the blood of vertebrate animals, causing significant economic impact in sub-Saharan Africa.

Hemiptera: Hemiptera is an insect order known as true bugs, with over 80,000 species including aphids, cicadas, and bed bugs. They have piercing-sucking mouthparts and range in size from 1 mm to 15 cm. The term "true bugs" is commonly used for the suborder Heteroptera.

Aphid: Aphids are small sap-sucking insects belonging to the superfamily Aphidoidea, commonly known as greenfly and blackfly. They vary in color and can include fluffy white woolly aphids. Their life cycle involves flightless females giving birth to female nymphs, with some already pregnant, resulting in rapid multiplication. Winged females appear later in the season to colonize new plants. In temperate regions, they have a phase of sexual reproduction in autumn, often overwintering as eggs.

Bed bug: Bed bugs are parasitic insects that feed on blood, causing health impacts such as rashes, psychological effects, and allergies. Their bites result in skin changes, itching, and possible fatigue or fever. Bed bugs do not transmit infectious diseases, but complications like dead skin or vasculitis can occur rarely.

Cicada: Cicadas are insects in the superfamily Cicadoidea, found in the Hemiptera order. They belong to the suborder Auchenorrhyncha, which includes leafhoppers and froghoppers. The superfamily consists of two families, Tettigarctidae (two species in Australia) and Cicadidae (over 3,000 species worldwide, with many still undescribed).

Leafhopper: Leafhoppers, also known as hoppers, are small insects that feed on plant sap. They have hind legs designed for jumping and secrete a water-repellent substance containing pheromones. Leafhoppers undergo a partial metamorphosis and have a range of host associations. They are found globally with at least 20,000 identified species. Some species are pests or vectors for plant viruses and phytoplasmas. The Cicadellidae family is the second largest group of hemipterans.

Scale insect: Scale insects are small insects with diverse appearances and extreme differences between males and females. They are herbivores that pierce plants to feed on sap, producing honeydew which attracts sooty mold. Females lack limbs and are covered by protective domed scales. Some species are hermaphroditic, and males resemble small flies with legs and sometimes wings. Ants often form mutualistic relationships with scale insects, feeding on honeydew and protecting them. There are approximately 8,000 known species.

Whitefly: Whiteflies are Hemipterans that suck sap from plant leaves. They belong to the family Aleyrodidae, which is the only family in the superfamily Aleyrodoidea. Over 1550 whitefly species have been identified.

Hymenoptera: Hymenoptera is a large insect order including sawflies, wasps, bees, and ants. This diverse group consists of over 150,000 known species, with some being extinct. Many Hymenoptera species are parasitic. Females have a specialized ovipositor that can act as a stinger. These insects undergo holometabolism, characterized by larval and pupal stages before reaching maturity.

Ant: Ants are eusocial insects that evolved from vespoid wasps. They belong to the order Hymenoptera and have around 13,800 classified species out of an estimated total of 22,000. Ants are easily recognized by their elbowed antennae and the node-like structure of their waists.

Carpenter ant: Carpenter ants are large ants found in forested areas worldwide.

Fire ant: Fire ants are a group of over 200 stinging ant species in the Solenopsis genus. They are known for their painful stings, and are commonly referred to as ginger ants or tropical fire ants. Other species of ants, such as Myrmica rubra and Pogonomyrmex barbatus, are sometimes mistakenly called red ants due to their similar coloration.

Bee: Bees are winged insects closely related to wasps and ants. They are known for their roles in pollination and honey production. There are over 20,000 known species of bees, living in colonies or as solitary insects. Bees play a crucial role in maintaining ecosystems and are considered a clade within the superfamily Apoidea.

Bumblebee: A bumblebee is a type of bee found in the Northern Hemisphere. They belong to the genus Bombus and are known for their ability to sting repeatedly. Bumblebees primarily live in higher altitudes or latitudes and are also found in South America. Some species have been introduced to New Zealand and Tasmania.

Africanized bee: The Africanized bee, commonly known as the "killer bee", is a hybrid of the western honey bee. It was created by crossbreeding the East African lowland honey bee with European honey bee subspecies like the Italian and Iberian honey bees.

Western honey bee: The western honey bee, also known as the European honey bee, is the predominant species among 7-12 honey bee species globally. Its genus name, Apis, means "bee" in Latin, while mellifera refers to its honey production.

Wasp: A wasp is an insect from the suborder Apocrita in the Hymenoptera order, distinct from bees and ants. It is not a clade, but bees and ants have evolved from wasp ancestors. Some wasps can sting their prey.

Hornet: Hornets are the largest eusocial wasps, resembling yellowjackets. Some can grow up to 5.5 cm in length. They have a distinctively large top margin on their heads. There are 22 recognized species of Vespa worldwide, mostly found in the tropics of Asia. However, the European hornet is widely distributed in Europe, Russia, North America, and north-eastern Asia. In North America, wasps in the Dolichovespula genus are often called hornets but are actually yellowjackets.

Lepidoptera: Lepidoptera is an order of winged insects, encompassing butterflies and moths. With 180,000 described species, it represents 10% of all known living organisms. It is the second-largest insect order, comprising 126 families, 46 superfamilies, and is highly recognizable worldwide.

Butterfly: Butterflies are colorful, winged insects belonging to the suborder Rhopalocera. They have large, vibrant wings that fold when resting and fly with a distinct flutter. Butterflies are part of the superfamilies Hedyloidea and Papilionoidea. Fossil records suggest their existence since the Paleocene, roughly 56 million years ago.

Swallowtail butterfly: Swallowtail butterflies are a diverse group of over 550 large and colorful butterfly species found on every continent except Antarctica. They are known for including the world's biggest butterflies, the Ornithoptera birdwings.

Pieris brassicae: Pieris brassicae, known as the large white or cabbage butterfly, is a butterfly species belonging to the Pieridae family. It is closely related to the small white butterfly, Pieris rapae. Its common name, the cabbage butterfly, reflects its habit of feeding on cabbage plants. The large white butterfly can be found in various regions, including India where it is referred to as the large cabbage white.

Bombyx mori: The domestic silk moth, Bombyx mori, is a valuable insect known for its production of silk. It is closely related to the wild silk moth, Bombyx mandarina. The larva of the silk moth is called a silkworm, which feeds on white mulberry leaves. Domestic silk moths have been selectively bred by humans for thousands of years, making them entirely dependent on humans for reproduction. Wild silk moths, on the other hand, are not as useful for silk production.

Geometer moth: Geometer moths, belonging to the family Geometridae, are insects in the order Lepidoptera. They are named after the way their larvae, known as inchworms, appear to measure the earth as they move. With around 23,000 described species, they are a large family, and over 1,400 species are indigenous to North America alone. Notable among them is the peppered moth, studied extensively in population genetics. Geometer moths include several pest species.

Lymantria dispar dispar: Lymantria dispar dispar, also called the gypsy moth, is a widespread moth species originally from Eurasia. It belongs to the Erebidae family and can be found in Europe, Africa, and North America.

Moth: Moths are a diverse group of insects, belonging to the order Lepidoptera but distinct from butterflies. They outnumber butterflies and comprise around 160,000 species, with numerous undescribed ones. Moths are mainly nocturnal, though some are active during dawn and dusk.

Odonata: Odonata is an order of flying insects, comprising dragonflies and damselflies. Dragonflies are generally larger, with spread-out wings at rest and large compound eyes, while damselflies are smaller, with folded wings along their bodies and eyes placed apart. Although adult odonates can land, they rarely walk.

Damselfly: Damselflies are small flying insects found on every continent except Antarctica. They belong to the suborder Zygoptera and have slim bodies. Unlike dragonflies, they fold their wings along their body when at rest. These fascinating creatures have been around since the Jurassic period.

Dragonfly: Dragonflies are flying insects with large compound eyes and strong transparent wings. There are about 3,000 known species, mostly found in tropical regions. Loss of wetland habitat poses a threat to their populations worldwide. Their bodies are elongated and many have vibrant iridescent or metallic colors. Adult dragonflies' compound eyes have around 24,000 ommatidia each.

Orthoptera: Orthoptera is an insect order that includes grasshoppers, locusts, and crickets along with related insects like bush crickets and wētā. It is divided into two suborders: Caelifera, which comprises grasshoppers and locusts, and Ensifera, which includes crickets and related species.

Cricket (insect): Crickets are orthopteran insects related to bush crickets and grasshoppers. They are now classified in the superfamily Grylloidea. The term is also used to describe related insects like king crickets and mole crickets.

Grasshopper: Grasshoppers are ancient chewing herbivorous insects that have been around for 250 million years. They belong to the suborder Caelifera and are among the most ancient living groups of insects.

Mole cricket: Mole crickets are fossorial insects known for their cylindrical bodies and burrowing capabilities. They belong to the Gryllotalpidae family in the Orthoptera order. These insects grow up to 3-5 cm long and have small eyes and shovel-like forelimbs for digging. Mole crickets can be found worldwide and may become agricultural pests in new regions.

Locust: Locusts are a type of grasshopper that have a swarming phase. They are usually solitary but can become gregarious under certain conditions. There is no taxonomic distinction between locusts and grasshoppers, the defining factor is their ability to form swarms. This behaviour has evolved independently in at least 18 genera across 5 different subfamilies of the Acrididae family.

Tettigoniidae: Tettigoniidae, or katydids, are insects in the suborder Ensifera. They are also known as bush crickets or long-horned grasshoppers. With over 8,000 known species, they are the only family in the superfamily Tettigonioidea that still exists today.

Hexapoda: Hexapoda is a subphylum of arthropods including the largest number of species. It consists of Insecta and a smaller class called Entognatha. Insects and springtails are major pollinators, consumers, scavengers, and micropredators in terrestrial habitats.

Springtail: Springtails, or Collembola, are the largest of the modern hexapods no longer classified as insects. While grouped in the class Entognatha due to their internal mouthparts, they are not more closely related to each other or insects with external mouthparts.

Myriapoda: Myriapoda is a subphylum of arthropods including millipedes and centipedes. It consists of approximately 13,000 terrestrial species.

Centipede: Centipedes are venomous arthropods with elongated segmented bodies and one pair of legs per segment. They belong to the class Chilopoda and are part of the larger group of Myriapoda, which includes millipedes. Centipedes inject venom through modified legs called forcipules, but do not have fangs. Despite their name, the number of legs in centipedes ranges from 15 to 191 pairs and is always an odd number.

Millipede: Millipedes, scientifically called Diplopoda, are arthropods with two pairs of legs on most body segments. They have elongated bodies with more than 20 segments, although pill millipedes are shorter and can curl up into a ball. Contrary to their name meaning "thousand feet," no species had more than a thousand legs until the discovery of Eumillipes persephone in 2020. There are around 12,000 named species of millipedes, making Diplopoda the largest class of myriapods, which includes centipedes and other multi-legged creatures.

Chelicerata: Chelicerata is a subphylum of Arthropoda, containing sea spiders, horseshoe crabs, arachnids, and some extinct species. Key features include a variety of arthropods with specialized appendages called chelicerae and the inclusion of both living and extinct lineages.

Xiphosura: Xiphosura is an order of arthropods, closely related to arachnids, commonly known as horseshoe crabs. They originated in the Hirnantian period and only four living species exist today. Xiphosura includes the suborder Xiphosurida and several stem-genera.

Eurypterid: Eurypterids, commonly known as sea scorpions, were diverse arthropods that lived around 467.3 million years ago. They first appeared in the Early Ordovician or Late Cambrian period and became prominent during the Silurian. Eurypterids were the most diverse chelicerate order of the Paleozoic era, with about 250 species. The genus Eurypterus from the Silurian comprises over 90% of the known specimens. Despite diversifying in the Devonian period, they were greatly impacted by the Late Devonian extinction event and eventually went extinct during the Permian-Triassic extinction event around 251.9 million years ago.

Trilobite: Trilobites were ancient marine arthropods that existed for about 270 million years. They were one of the earliest groups of arthropods and had over 22,000 species. Trilobites first appeared in the fossil record during the Early Cambrian period and thrived until the Devonian, when most orders became extinct. The last trilobites disappeared during a mass extinction at the end of the Permian, about 251.9 million years ago. Despite their extinction, trilobites were incredibly successful and played a significant role in early ocean ecosystems.

Mollusca: Mollusca is the second-largest phylum in the animal kingdom, comprising mollusks. There are around 76,000 known living species and an estimated 60,000 to 100,000 fossil species. The proportion of undescribed species is considerably high, leaving many taxa poorly studied.

Clam: Clams are bivalve molluscs that are often edible and live halfway buried in sand or mud. They have two equal-sized shells and a strong burrowing foot, and can be found in both freshwater and marine environments. Clam diversity is highest in North America.

Mussel: Mussels are bivalve molluscs found in both saltwater and freshwater. They have elongated and asymmetrical shells, distinguishing them from other edible clams that are more rounded or oval.

Oyster: Oyster is a type of salt-water bivalve mollusc found in marine or brackish environments. It has calcified valves and often exhibits irregular shapes. Some oysters belong to the Ostreoidea superfamily.

Scallop: A scallop is a type of marine mollusk belonging to the Pectinidae family. It includes different species, and the common name "scallop" is also used for similar species in related families like thorny oysters.

Octopus: Octopuses are soft-bodied molluscs with eight limbs, belonging to the order Octopoda. They can alter their shape to fit through small spaces and use a siphon for breathing and movement. As part of the class Cephalopoda, they share characteristics with squids, cuttlefish, and nautiloids. Octopuses possess a complex nervous system, excellent eyesight, and are highly intelligent and behaviorally diverse.

Squid: A squid is a soft-bodied mollusc with a distinct head, large eyes, and eight arms. They also have two tentacles and often possess a rod-like internal skeleton. Squid are part of the Decapodiformes superorder, although other molluscs are sometimes called squid.

Slug: A slug is a shell-less terrestrial gastropod mollusc often referred to as part of the common name for any mollusc without a shell, including sea slugs and semi-slugs.

Snail: A snail is a shelled gastropod that includes land, sea, and freshwater species. They have a coiled shell that allows complete retraction for protection. Snails are part of the Gastropoda class, while shell-less or partially shelled land snails are known as slugs or semi-slugs.

Conch: The term 'Conch' refers to several medium-to-large-sized sea snails with distinct features such as a high spire and a noticeable siphonal canal.

Cnidaria: Cnidaria is a phylum of aquatic animals found in freshwater and marine environments, such as jellyfish, sea anemone, corals, and tiny marine parasites. They have a decentralized nervous system and specialized cells called cnidocytes or cnidoblasts for envenomation and capturing prey. Their bodies are composed of a gelatinous substance called mesoglea, protected by thin layers of epithelium.

Coral: Corals are marine invertebrates that form colonies of polyps. They are vital for building reefs in tropical oceans by secreting calcium carbonate to create a hard skeleton.

Jellyfish: Jellyfish, or sea jellies, are gelatinous creatures that belong to the subphylum Medusozoa, which is a significant group within the phylum Cnidaria.

Echinoderm: Echinoderms are marine animals with radial symmetry found at every ocean depth. They include starfish, sea urchins, and sea cucumbers. With about 7,000 living species, they are the second-largest group of deuterostomes, after chordates. Echinoderms are the largest marine phylum and first appeared in the Cambrian period.

Sea cucumber: Sea cucumbers are marine echinoderms with a leathery skin and an elongated body. They have a single, branched gonad and are found worldwide on the sea floor. There are about 1,786 known species, with the highest number in the Asia-Pacific region. Some are harvested for human consumption and cultivated in aquaculture systems. Sea cucumbers play a vital role in the marine ecosystem by recycling nutrients and aiding in the decomposition of detritus and organic matter.

Sea urchin: Sea urchins are spiny echinoderms found in oceans worldwide. They vary in species, with about 950 types inhabiting different depths. Their hard shells are spherical and covered in spines, ranging from 3 to 30 cm in length. Sea urchins move slowly using tube feet and eat algae as well as other slow-moving animals. They face predators such as fish, starfish, crabs, marine mammals, and even humans.

Starfish: Starfish, or sea stars, are star-shaped echinoderms from the class Asteroidea. They are often confused with brittle stars or basket stars. These creatures, also known as asteroids, live in various marine environments worldwide, ranging from tropical to polar regions. With around 1,900 species, starfish inhabit ocean floors from the intertidal zone to depths of 6,000 m (20,000 ft).

Sponge: Sponges, part of the Porifera phylum, are primitive animals closely related to diploblasts. They are multicellular and characterized by their porous bodies and intricate water circulation system. Sponges consist of a jelly-like mesohyl sandwiched between two thin cell layers.

Nematode: Nematodes, or roundworms, are a diverse group of animals found in various environments. While most species are free-living and feed on microorganisms, many nematodes are parasitic. The parasitic nematodes, known as helminths, are responsible for soil-transmitted helminthiases.

Caenorhabditis elegans: Caenorhabditis elegans is a type of nematode that is about 1 mm in length. It is a free-living, transparent organism found in temperate soil environments. The name combines Greek and Latin words to describe its recent, elegant, and rod-like characteristics. Initially named Rhabditides elegans, it was later placed in the subgenus Caenorhabditis and ultimately raised to the status of a genus.

Tardigrade: Tardigrades, also called water bears or moss piglets, are tiny segmented animals with eight legs. They were originally identified by Johann August Ephraim Goeze in 1773, who named them Kleiner Wasserbär. Later, Lazzaro Spallanzani coined the term Tardigrada, meaning "slow steppers."

Annelid: Annelids, or segmented worms, make up a vast phylum with over 22,000 species. They can be found in diverse habitats such as marine tidal zones, hydrothermal vents, freshwater, and moist terrestrial environments. Some well-known examples are earthworms, leeches, and ragworms.

Leech: Leeches are segmented worms that are either parasites or predators. They are closely related to earthworms and have soft, muscular bodies that can stretch. Leeches have suckers at both ends and ring markings that don't match their internal segments. They are hermaphrodites with a clitellum. Leeches have a muscular and solid body, with a reduced spacious body cavity called a coelom.

Polychaete: Polychaetes are marine annelid worms with bristles and fleshy protrusions called parapodia. They are a diverse group with over 10,000 species, including well-known examples like the lugworm and clam worm.

Earthworm: An earthworm is a soil-dwelling invertebrate belonging to the phylum Annelida. It is the largest member of the class Oligochaeta and is commonly known by various names like "dew-worm", "rainworm", and "nightcrawler". Earthworms have a distinct clitellum and a vascular system with true capillaries. They are part of the suborder Lumbricina, although their classification may change. They are found in terrestrial environments and are different from microdriles found in semi-aquatic families.

Bryozoa: Bryozoa are small aquatic invertebrate animals living in sedentary colonies. They have a lophophore, a feeding structure with tentacles for filter feeding. Most are found in tropical waters, but some live in oceanic trenches and polar waters. They are classified into marine, freshwater, and mostly-marine species. There are 5,869 known living species, with only a few solitary genera.

Flatworm: Flatworms, or Platyhelminthes, are simple invertebrates with a flattened body shape. They lack specialized circulatory and respiratory organs, which limits their form to facilitate oxygen and nutrient exchange through diffusion. They are acoelomates, meaning they lack a body cavity, and their digestive system has a single opening for both taking in and eliminating food. This restricts their ability to process food continuously.

Cestoda: Cestoda is a class of parasitic flatworms. The subclass Eucestoda includes ribbon-like tapeworms, known for their proglottids that contain eggs shed to infect other organisms. The other subclass, Cestodaria, primarily consists of fish-infecting parasites.

Green algae: Green algae are a diverse group that includes unicellular and colonial flagellates, as well as various forms of seaweed. They are part of the larger clade Viridiplantae, which also includes land plants. With approximately 22,000 species, green algae display a range of lifestyles, from single-cell organisms to complex multicellular seaweeds.

Charophyta: Charophyta is a group of freshwater green algae known as charophytes. They are sometimes considered a division, superdivision, or an unranked clade. Terrestrial plants, called Embryophyta, evolved from Charophyta, possibly from unicellular charophytes. The class Zygnematophyceae is closely related to Charophyta.

Chlorophyta: Chlorophyta, also known as chlorophytes, is a taxon of green algae. It can refer to either a diverse group of green algae, including about 7,000 species, or a narrower group that includes about 4,300 species. These organisms are mainly found in freshwater environments. Like land plants, they contain chlorophyll a and chlorophyll b, and store food as starch in their plastids.

Lycophyte: Lycophytes are ancient vascular plants that include the clubmosses. They are among the oldest living plants and have extinct species dating back to the Silurian period. Lycophytes were dominant during the Carboniferous period, with tree-like species reaching over 40 meters in height. However, modern lycophytes are relatively small plants.

Bryophyte: Bryophytes are non-vascular land plants, including liverworts, hornworts, and mosses. They are small in size and thrive in moist environments, but can adapt to drier conditions. With around 20,000 species, they reproduce through spores and fragmentation, lacking flowers or seeds. Recent evidence supports the classification of bryophytes as a monophyletic group. The term "bryophyte" stems from the Greek words for tree moss and plant.

Hornwort: Hornworts are non-vascular plants belonging to the division Anthocerotophyta. They are characterized by elongated horn-like structures called sporophytes. Like mosses and liverworts, hornworts have a life cycle dominated by the gametophyte stage, and their plant body is green and flattened.

Marchantiophyta: The Marchantiophyta, also known as hepatics or liverworts, are non-vascular land plants. They have a gametophyte-dominant life cycle and carry only one set of genetic information.

Moss: Mosses are small, non-vascular plants that belong to the taxonomic division Bryophyta. They form dense green clumps in damp or shady places. Mosses have simple leaves, attached to a stem with limited water and nutrient conducting ability. They reproduce without seeds and develop sporophytes with capsules containing spores. Mosses vary in height, with the tallest known species reaching 50 cm. There are approximately 12,000 species of moss worldwide.

Sphagnum: Sphagnum is a genus of mosses known as sphagnum moss or bog moss. It has around 380 accepted species. Sphagnum can store significant amounts of water in both living and dead plants. Its cells can hold 16 to 26 times more water than their dry weight. The empty cells also aid in retaining water in dry conditions.

Pteridophyte: Pteridophytes are non-flowering vascular plants that disperse spores for reproduction. They are commonly known as "cryptogams" since they lack flowers and seeds.

Fern: Ferns are vascular plants that reproduce through spores and lack seeds or flowers. They have specialized tissues for conducting water and nutrients, distinguishing them from mosses. The dominant phase of their life cycle is the branched sporophyte.

Equisetum: Equisetum is a single genus in the Equisetaceae family, consisting of vascular plants that reproduce through spores instead of seeds.

Gymnosperm: Gymnosperms are seed-producing plants like conifers, cycads, Ginkgo, and gnetophytes. The name comes from the Greek word for "naked seeds" because their seeds are not enclosed within an ovary. Gymnosperm seeds develop on scales, leaves, or independently. Their life cycle involves both a dominant diploid sporophyte phase and a reduced haploid gametophyte phase. The term is often used to refer to all non-flowering seed plants in paleobotany.

Cycad: Cycads are seed plants with stout trunks and crown of large evergreen leaves. They come in different sizes, have separate male and female plants, and grow slowly. Though often mistaken for palms or ferns, they are not related to either group.

Ginkgo biloba: Ginkgo biloba, also known as ginkgo or maidenhair tree, is a gymnosperm tree native to East Asia. It is the last living species in the Ginkgoales order, dating back over 290 million years. Fossils resembling the modern species have been found from around 170 million years ago. As a living fossil, ginkgo has been cultivated throughout human history and is still commonly planted today.

Conifer: Conifers are cone-bearing seed plants, part of the Pinophyta division. They are mostly trees with secondary growth. Examples include cedars, Douglas-firs, cypresses, pines, and spruces. The division contains 7 families, 60-65 genera, and over 600 living species.

Cupressus: Cupressus is a genus of evergreen conifers in the family Cupressaceae. It is known as cypress and is considered a polyphyletic group. The genus Cupressus is found in the subfamily Cupressoideae. The common name "cypress" originated from the Old French cipres, derived from the Latin cyparissus, which in turn is the Latin version of the Greek word κυπάρισσος (kypárissos).

Juniper: Junipers are coniferous trees and shrubs found widely in the Northern Hemisphere. There are between 50 and 67 species of junipers, distributed from the Arctic to tropical Africa, and throughout parts of Asia and Central America. They can grow at high altitudes, with the highest-known juniper forest located in southeastern Tibet and the northern Himalayas, forming one of the highest tree lines on earth at 4,900 meters (16,100 ft).

Sequoioideae: Sequoioideae, also known as Redwoods, are a subfamily of coniferous trees in the Cupressaceae family. They are found in the northern hemisphere and are admired for being the largest and tallest trees in the world. These remarkable trees are frequently planted as ornamentals. Austrosequoia, a related genus, thrived until the Oligocene epoch in prehistoric times.

Cedrus: 'Cedrus', commonly known as cedar, is a genus of coniferous trees in the Pinaceae family. These trees are found in the western Himalayas and the Mediterranean region, with altitudes ranging from 1,000 to 3,200 m.

Douglas fir: The Douglas fir, a pine tree species, is native to western North America. It is an evergreen conifer and has three varieties: coast, Rocky Mountain, and Mexican Douglas-fir. Also known as Douglas-fir, it is sometimes referred to as Douglas spruce, Oregon pine, or Columbian pine.

Fir: Firs are evergreen coniferous trees in the Abies genus (Pinaceae family). They include around 48-56 species found in mountainous regions across North and Central America, Europe, Asia, and North Africa. Firs are closely related to Cedrus (cedar).

Pine: A pine is a coniferous tree in the genus Pinus of the Pinaceae family. There are 187 recognized species of pines, with 121 species accepted by various societies. Pines are primarily found in the Northern Hemisphere and their lumber is widely used. The pine family is the largest conifer family with 818 named cultivars recognized by the ACS. Pines are also famous as Christmas trees.

Spruce: Spruce trees are coniferous evergreen trees found in the northern temperate and boreal regions. They belong to the genus Picea and are distinguished by their large size, whorled branches, and conical shape. Spruce needles are four-sided and attach singly to peg-like structures on the branches. Their cones hang downwards after pollination. Unlike other pine family members, spruce trees have rough branches due to retained pegs.

Podocarpus: Podocarpus is a widespread genus of conifers in the Podocarpaceae family, known for being evergreen shrubs or trees. They can reach heights of up to 40 meters and have cone scales that fuse together to form a colorful, berry-like receptacle. These fleshy cones attract birds, aiding in seed dispersal. The genus comprises around 97 to 107 different species, depending on classification.

Araceae: Araceae is a family of flowering plants characterized by flowers borne on a spadix within a spathe. It is commonly known as the arum family or aroids. With 140 genera and around 4,075 known species, it is most diverse in the New World tropics but also found in Old World tropics and northern temperate regions.

Anthurium: Anthurium is a large genus of flowering plants, with approximately 1,000 species. It belongs to the arum family, Araceae. Common names for Anthurium include tailflower, flamingo flower, and laceleaf.

Philodendron: Philodendron is a popular genus of flowering plants in the Araceae family. It is the second-largest genus in the family, with around 489 accepted species. Despite its popularity, there are still many undescribed species within the genus. Philodendrons are commonly grown as ornamental and indoor plants. The name Philodendron comes from Greek and means "love for trees." It is often used as the English name for these plants.

Arecaceae: Arecaceae is a family of perennial plants known as palms. They can be climbers, shrubs, or tree-like with large, compound, evergreen leaves called fronds. Palm trees are the ones with a tree-like form. There are 181 genera and around 2,600 species, mostly found in tropical and subtropical climates. Palms are diverse in physical characteristics and adapt to various habitats, ranging from rainforests to deserts.

Agave: Agave is a genus of plants mostly found in arid regions of the Americas and the Caribbean, with some species also existing in temperate and tropical areas of North America. Known for their succulent and drought-resistant nature, these plants grow in rosettes with thick, fleshy leaves. The genus has absorbed species from other genera like Manfreda, ×Mangave, Polianthes, and Prochnyanthes.

Aloe: Aloe is a genus of over 650 flowering succulent plants. The most famous species is Aloe vera, cultivated as a primary source for various pharmaceutical uses. Other species like Aloe ferox are also utilized for similar purposes, either cultivated or harvested from the wild.

Amaryllis: Amaryllis is a small genus of flowering bulbs with two species. Amaryllis belladonna, the better known species, is native to the rocky southwest area between the Olifants River Valley and Knysna in the Western Cape region of South Africa.

Gladiolus: The Gladiolus is a perennial flowering plant found in the iris family. It has corms and produces beautiful flowers.

Iridaceae: Iridaceae is a plant family in the order Asparagales, commonly known as irises. With a broad global distribution, it consists of 69 accepted genera and approximately 2500 species. Notably, it includes economically important plants like Freesia, Gladiolus, Crocus, and saffron.

Iris(plant): Iris is a genus of 310 flowering plant species known for their showy flowers. The name applies to all Iris species, including those in closely related genera. Some species are also called flags, while those in the Scorpiris subgenus are known as junos. This popular garden flower is widely used in horticulture.

Lily of the valley: The Lily of the valley is a woodland plant with sweetly scented white bell-shaped flowers. It grows in Asia, Europe, and North America.

Narcissus(plant): Narcissus is a spring-flowering perennial plant, belonging to the amaryllis family, and is commonly known as daffodil, narcissus, or jonquil. It has distinctive flowers with six petal-like tepals and a cup- or trumpet-shaped corona. The flowers are mostly white and yellow, with varying colors in the tepals and corona.

Orchid: Orchids are flowering plants known for their vibrant and fragrant blooms, and they belong to the Orchidaceae family. They are found in all habitats on Earth, except glaciers, and are most diverse in tropical regions.

Yucca: Yucca is a genus of shrubs and trees known for their evergreen, sword-shaped leaves and large clusters of white flowers. With around 40-50 species, they are found across the Americas and the Caribbean, adapting to diverse environments from rainforests to arid deserts. Part of the Asparagaceae family, Yuccas are characterized by their tough foliage and ability to thrive in various habitats.

Pontederia crassipes: Pontederia crassipes, also called common water hyacinth, is an aquatic plant native to South America but now found worldwide. It is invasive and can quickly spread beyond its natural habitat. It is the only species in its subgenus and is notorious for its aggressive growth, earning the nickname "terror of Bengal."

Alstroemeria: Alstroemeria, known as the Peruvian lily or lily of the Incas, is a South American genus of flowering plants. They are native to South America, with some species found in the United States, Mexico, Australia, New Zealand, Madeira, and the Canary Islands. There are two centers of diversity for Alstroemeria: central Chile and eastern Brazil. The Chilean species are winter-growing, while the Brazilian ones are summer-growing. Most Alstroemeria species are long-lived perennials, except for A. graminea, an annual found in the Atacama Desert of Chile.

Colchicum: Colchicum is a toxic genus of perennial flowering plants with around 160 species. They grow from bulb-like corms and belong to the Colchicaceae family. Colchicum is native to West Asia, Europe, parts of the Mediterranean and East African coasts. The flowers have underground ovaries, resulting in exceptionally long styles, often over 10 cm.

Liliaceae: Liliaceae is a family of flowering plants with around 610 species in 15 genera. They are monocotyledonous perennials, often bulbous geophytes, with large flowers arranged in threes. The leaves are linear and parallel-veined. Most species are grown from bulbs or rhizomes. The family has diverse morphology despite genetic similarity. Originally described in 1789, it is now a catch-all group for various lilioid monocots that do not fit into other families or orders.

Lilium: Lilium is a genus of flowering plants with large, prominent flowers. They are known as the true lilies and are culturally significant worldwide. Native to the Northern Hemisphere, they thrive in temperate climates and subtropics. Other plants may have "lily" in their names, but they are not true lilies and belong to different genera.

Tulip: Tulips are perennial flowers known for their large and brightly colored blooms. They belong to the Tulipa genus and can be red, orange, pink, yellow, or white, often with a different colored blotch at the base. Classification of tulips has been complex due to variability and cultivation history. They are part of the lily family, Liliaceae, closely related to Amana, Erythronium, and Gagea in the Lilieae tribe.

Pandanus: Pandanus is a genus of palm-like trees and shrubs found in the Old World tropics and subtropics. With 578 accepted species, it is known for its dioecious nature and is native to Madagascar and Malaysia. Commonly called pandan, screw palm, or screw pine, these plants belong to the Pandanales order and Pandanaceae family.

Bromeliaceae: The Bromeliaceae is a family of flowering plants, consisting of approximately 80 genera and 3700 known species. Mostly found in the tropical Americas, with a few species in American subtropics and one in tropical west Africa (Pitcairnia feliciana).

Puya(plant): Puya is a genus of the Bromeliaceae family, consisting of 226 species primarily found in the Andes Mountains of South America and southern Central America. These terrestrial plants are unique as they belong to the subfamily Puyoideae. One notable characteristic is that many Puya species are monocarpic, meaning they die after producing only one flower and set of seeds.

Spanish moss: Spanish moss is a flowering plant that thrives on trees in tropical and subtropical areas. It can be found in Mexico, Bermuda, the Bahamas, Central and South America, the Southern United States, and the West Indies. This epiphytic plant is known as "grandpa's beard" in French Polynesia and even naturalized in Queensland, Australia.

Cyperaceae: Cyperaceae is a family of flowering plants known as sedges. It includes around 5,500 species in about 90 genera, with the largest genus being Carex, which has over 2,000 species.

Juncus: Juncus is a large genus of flowering plants known as rushes, belonging to the family Juncaceae. With around 300 species, it is the largest genus in this family.

Poaceae: Poaceae, also known as Gramineae, is a widespread family of flowering plants called grasses. It encompasses cereal grasses, bamboos, grasses found in natural grasslands, and those cultivated in lawns and pastures. Collectively, these are referred to as grass.

Bamboo: Bamboo is a diverse group of perennial plants in the grass family. Some species, like Dendrocalamus sinicus, can grow up to 46 meters long and weigh up to 450 kilograms. They have long internodes, with some reaching up to 5 meters in length. However, there are also small varieties like Raddiella vanessiae, which are only 10-20 millimeters long. The word "bamboo" has uncertain origins but likely originated from Dutch, Portuguese, Malay, or Kannada languages.

Sugarcane: Sugarcane is a flowering plant belonging to the grass family and is used for sugar production. It has tall stalks rich in sucrose, primarily grown in tropical regions. In 2020, it was the world's largest crop, with Brazil being the top producer. Sugarcane accounts for 79% of global sugar production, and the main commercial varieties are hybrids of Saccharum officinarum.

Typha: Typha is a genus of around 30 monocotyledonous flowering plants in the Typhaceae family. They are known by various names, such as bulrush, reedmace, reed, cattail, punks, cumbungi, and raupo, depending on the country. Some sedges in Scirpus and related genera can also be referred to as bulrush.

Canna(plant): Canna, also known as canna lily, is a genus of flowering plants belonging to the family Cannaceae. It includes 10 species that are native to the American tropics and have been naturalized in Europe, India, and Africa since the 1860s. While originally tropical, most cultivars have been developed in temperate climates and can be easily grown in many countries as long as they receive 6-8 hours of sunlight during the summer and are moved to a warm location in winter. You can find photographs of various Canna cultivars in the Canna cultivar gallery.

Heliconia: Heliconia is a genus of flowering plants in the Heliconiaceae family. It includes 194 species, mainly found in the tropical Americas and a few islands in the western Pacific and Indonesia. These plants mostly thrive in tropical forests. Some Heliconia species are vulnerable or data deficient according to the IUCN Red List. Many species are cultivated as ornamentals, and a few have naturalized in places like Florida, Gambia, and Thailand.

Apiaceae: Apiaceae, also known as the celery family, is a family of aromatic flowering plants, including well-known plants like carrot, celery, and parsley. It is the 16th-largest family of flowering plants, with over 3,800 species in about 446 genera, and contains economically important plants such as caraway, coriander, and dill. The family also includes the uncertain and possibly extinct plant called silphium.

Hedera: Hedera is a genus of evergreen climbing or ground-creeping plants in the Araliaceae family. It consists of 12-15 species native to Western Europe, Central Europe, Southern Europe, Macaronesia, northwestern Africa, and central-southern Asia. These plants are commonly known as ivy and are cultivated for their ornamental climbing. The most recognizable species, known as English ivy in North America, is frequently planted to cover brick walls.

Asteraceae: Asteraceae, also known as Compositae, is a plant family consisting of over 32,000 known species in over 1,900 genera. It belongs to the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, it was first described in 1740. With its extensive species count, Asteraceae is only rivaled by Orchidaceae. The exact family with more species remains uncertain as the total number of species in each family is unknown.

Bellis perennis: Bellis perennis, also called the daisy, is a common European plant belonging to the Asteraceae family. It is recognized as the classic example of a daisy and is referred to as common daisy, lawn daisy, or English daisy to differentiate it from other daisy-like plants.

Chrysanthemum: Chrysanthemums, also known as mums or chrysanths, are flowering plants in the Asteraceae family. They are native to East Asia and northeastern Europe, with China being the center of diversity. Chrysanthemums have numerous horticultural varieties and cultivars.

Cirsium: Cirsium is a genus of flowering plants in the Asteraceae family, commonly known as thistles. They are called plume thistles due to their feathered hairs on their achenes, distinguishing them from other thistle genera that have unbranched hairs.

Dahlia: Dahlia is a vibrant genus of perennial plants native to Mexico and Central America. It belongs to the Asteraceae family, along with sunflowers, daisies, chrysanthemums, and zinnias. With 49 species and stunning flowers in a wide range of colors, dahlias are widely cultivated as beautiful garden plants.

Solidago: Solidago, or goldenrods, are flowering plants in the Asteraceae family. They consist of about 100-120 species, primarily herbaceous perennials. They are commonly found in open areas like meadows, prairies, and savannas. While most species are native to North America, including Mexico, some are also found in South America and Eurasia. Certain American species have been introduced to Europe and other regions around the globe.

Helianthus: Helianthus is a genus of flowering plants in the Asteraceae family, consisting of about 70 species, with most native to North and Central America. The common sunflower is the most well-known species. These plants are cultivated as food crops and ornamental plants. The primary growing season for Helianthus annuus is during the summer and early fall.

Sonchus: Sonchus is a genus of flowering plants in the Asteraceae family. They are commonly called sow thistles and can be annual, biennial, or perennial herbs. Some varieties have rhizomes and a few are even woody.

Tagetes: Tagetes is a genus of flowering plants in the Asteraceae family, with around 50 species. They are mostly annual or perennial herbs and are commonly known as marigolds. The genus was classified by Carl Linnaeus in 1753.

Taraxacum: Taraxacum is a large genus of flowering plants known as dandelions. It is native to Eurasia and North America, but two commonly found species, T. officinale and T. erythrospermum, were introduced from Europe to North America. These plants thrive in temperate regions and can be found in various habitats like yards, gardens, and roadsides. They are edible in their entirety and are often referred to as dandelions. The study of this genus is called taraxacology.

Campanulaceae: Campanulaceae is a plant family in the order Asterales, with around 2400 species in 84 genera. It includes herbaceous plants, shrubs, and sometimes small trees with milky sap. Garden favorites like Campanula, Lobelia, and Platycodon belong to this family. Some species like Campanula rapunculus and Codonopsis lanceolata are used as vegetables, while others like Lobelia inflata and L. siphilitica have medicinal uses. Campanula rapunculoides can be a pest in gardens, and Legousia spp. may appear in arable fields.

Arabidopsis thaliana: Arabidopsis thaliana, also known as thale cress or arabidopsis, is a small weed plant from the mustard family. It is native to Eurasia and Africa and commonly found on roadsides and disturbed land.

Tropaeolum: Tropaeolum, also known as nasturtium, is a genus of flowering plants with about 80 species. They are annual or perennial herbs and the only genus in the Tropaeolaceae family. These plants were named by Carl Linnaeus and are called nasturtiums due to their production of an oil similar to watercress.

Cactus: A cactus is a type of plant from the Cactaceae family, with about 1,750 known species. They come in various shapes and sizes and are native to the Americas. Cacti are well adapted to dry environments and have succulent stems to store water. They have spines instead of leaves to prevent water loss and provide shade. The stems also carry out photosynthesis.

Cornus: Cornus is a genus of 30-60 woody plants in the Cornaceae family, also known as dogwoods. These plants are typically recognized by their unique flowers, fruits, and bark. Most dogwoods are deciduous trees or shrubs, but some are herbaceous perennials or evergreens. They produce inconspicuous flowers surrounded by large, white petal-like bracts or clusters of petal-bearing flowers. Dogwoods are native to temperate and boreal regions of Eurasia and North America, especially China, Japan, and the southeastern United States.

Cucurbitaceae: The Cucurbitaceae, also known as cucurbits or the gourd family, consists of around 965 species in 95 genera. Some important members of this family include squash, pumpkin, zucchini, cucumber, watermelon, and bitter melon. The common name for luffa is also luffa, while cyclanthera is commonly known as Caigua.

Diospyros: Diospyros is a diverse genus of trees and shrubs, with over 700 species. They are native to tropical regions, but a few can be found in temperate areas. Ebony trees are valued for their hard and dark timber, while persimmon trees are known for their tasty fruit. Some species have ornamental value and play a vital role in local ecosystems. Most plants in this genus have separate male and female individuals.

Ericaceae: The Ericaceae family, also known as the heath or heather family, consists of flowering plants that thrive in acidic and infertile environments. With around 4,250 known species and 124 genera, it is the 14th most species-rich family of flowering plants. Notable members include cranberries, blueberries, huckleberries, rhododendrons, and common heaths and heathers, which hold economic importance.

Rhododendron: Rhododendron is a diverse genus of about 1,024 woody plants in the heath family. With both evergreen and deciduous varieties, they are native to eastern Asia, the Himalayan region, and other parts of Asia. Some species can also be found in North America, Europe, and Australia.

Azalea: Azaleas are flowering shrubs in the Rhododendron genus, known for their vibrant blooms that last for weeks in the spring. They thrive in shaded areas near or under trees and are part of the Ericaceae family.

Impatiens: Impatiens is a diverse genus of over 1,000 flowering plant species present across the Northern Hemisphere and tropical regions. It belongs to the Balsaminaceae family, alongside the Hydrocera genus.

Primulaceae: Primulaceae, also known as the primrose family, is a group of herbaceous and woody flowering plants. It includes popular garden plants and wildflowers, with most being perennial. However, there are also annual species like the scarlet pimpernel.

Theaceae: Theaceae, or the tea family, consists of shrubs and trees like the tea plant and ornamental camellias. It contains around 7 to 40 genera, varying based on sources. Ternstroemiaceae is sometimes included within Theaceae, but it is now recognized separately in Pentaphylacaceae. Most species, though not all, are native to China and East Asia.

Camellia: Camellia is a flowering plant genus found in tropical and subtropical areas of Asia. It belongs to the family Theaceae and encompasses over 220 known species. Camellias are well-known for their ornamental, tea, and woody-oil uses and have been cultivated worldwide for centuries. Over 26,000 cultivars, with more than 51,000 registered or published names, exist to date.

Fabaceae: Fabaceae, also known as the legume family, is a significant group of flowering plants. It consists of trees, shrubs, and herbaceous plants identifiable by their legume fruit and compound, stipulate leaves. With approximately 765 genera and nearly 20,000 known species, it is the third-largest land plant family after the Orchidaceae and Asteraceae. The Fabaceae family is widely distributed and holds great agricultural importance.

Mimosa: Mimosa is a genus of plants in the legume family, with around 600 species of herbs and shrubs. They are native to the Americas, eastern Africa, the Indian subcontinent, and Indochina. The name "Mimosa" comes from the Greek word for actor or mime, referring to the sensitive leaves that mimic conscious movement.

Alder: Alder trees (genus Alnus) are part of the birch family. There are around 35 species, including trees and shrubs. They are mostly found in the north temperate zone, with a few species in Central America and the Andes. Some alder trees grow to be quite large.

Birch: Birch is a hardwood tree genus, closely related to beech-oak family, found in the Northern Hemisphere. It belongs to the family Betulaceae along with alder, hazel, and hornbeam. The genus Betula includes around 30 to 60 species, 11 of which are listed as threatened. Birch trees are short-lived pioneers and are commonly found in temperate and boreal climates.

Beech: Beech is a genus of deciduous trees found in temperate Eurasia and North America. It consists of 10 to 13 species divided into two subgenera, Engleriana and Fagus. The Engleriana subgenus, exclusive to East Asia, is characterized by low branches composed of multiple trunks and yellowish bark. On the other hand, the Fagus subgenus is well-known for its high-branching trees with tall, sturdy trunks and smooth silver-grey bark. The European beech is the most commonly cultivated species.

Oak: An oak is a hardwood tree or shrub in the beech family, known for its spirally arranged leaves with lobed edges and the acorn nut it produces. There are about 500 species of oaks distributed in the Northern Hemisphere, both deciduous and evergreen. Fossil evidence shows oak trees have been around since the Middle Eocene. The genus Quercus is divided into Old World and New World clades, although hybridization between species makes their evolutionary history challenging to determine.

Hickory: Hickory refers to trees in the Carya genus, with around 18 species. They are found in China, Indochina, India, United States, Mexico, and Canada. Hickory species are valued for their edible nuts, lumber, and woodworking materials.

Apocynaceae: Apocynaceae is a diverse family of flowering plants, including trees, shrubs, herbs, succulents, and vines. Its common name is the dogbane family, as some species were used to poison dogs. The family is widespread, with members native to tropical and subtropical regions of Europe, Asia, Africa, Australia, and the Americas. The former family Asclepiadaceae is now considered a subfamily of Apocynaceae, with a total of 348 genera. A list of Apocynaceae genera can be found for more information.

Rubiaceae: Rubiaceae is a family of flowering plants known as coffee, madder, or bedstraw family. It includes terrestrial trees, shrubs, lianas, or herbs with simple, opposite leaves and sympetalous actinomorphic flowers. With around 13,500 species in 620 genera, it is the fourth-largest angiosperm family. Rubiaceae is found worldwide, but most diverse in the tropics and subtropics. Economically important genera include Coffea (coffee), Cinchona (quinine source), and ornamental and dye plants.

Gardenia: Gardenia is a flowering plant genus in the coffee family, native to Africa, Asia, Madagascar, Pacific Islands, and Australia.

Lamiaceae: Lamiaceae, also known as the mint or sage family, consists of flowering plants noted for their aromatic qualities. This family includes widely used culinary herbs like basil, rosemary, and thyme, as well as medicinal herbs such as catnip and bee balm. Lamiaceae plants are easy to cultivate and propagate, with some species being shrubs or trees. They are also grown for decorative foliage, seeds, and edible tubers. Notably, coleus and various Salvia species are grown ornamentally.

Salvia: Salvia is a diverse genus of plants in the sage family, with around 1000 species of shrubs, perennials, and annuals. It belongs to the Mentheae tribe in the Nepetoideae subfamily. Notably, Salvia includes popular herbs such as Salvia officinalis (common sage) and Salvia rosmarinus (rosemary).

Oleaceae: Oleaceae, also known as the olive family, is a taxonomic family of flowering shrubs, trees, and lianas. It consists of 28 genera, with one recently extinct. The family is globally distributed, from the subarctic to the southernmost parts of Africa, Australia, and South America. Notable plants include olives, ashes, jasmine, and popular ornamental plants like privet and lilac. There are around 700 species in the family, and the flowers are often abundant and highly fragrant.

Fraxinus: Fraxinus, known as ash, is a genus of deciduous and evergreen trees in the olive and lilac family. It consists of 45-65 species and is found widely across Europe, Asia, and North America.

Sesame: Sesame, a plant also known as benne or gingelly, is cultivated worldwide for its edible seeds. It is naturalized in tropical regions and has wild relatives in Africa and India. In 2018, global production reached 6 million metric tons, with Sudan, Myanmar, and India as the main producers.

Verbena: Verbena, also called vervain or verveine, is a genus of flowering plants in the family Verbenaceae. It comprises around 150 species of herbaceous or semi-woody plants that can be annual or perennial. Most of these plants are native to the Americas and Asia. However, the type species, Verbena officinalis, also known as common vervain or common verbena, is native to Europe.

Euphorbiaceae: Euphorbiaceae, or the spurge family, is a large family of flowering plants known as euphorbias. They include herbs, shrubs, and trees like Hevea brasiliensis. Some, like Euphorbia canariensis, resemble cacti due to convergent evolution. This cosmopolitan family has the highest species diversity in the tropics but is also found in nontropical regions on all continents except Antarctica.

Flax: Flax is a flowering plant, Linum usitatissimum, cultivated for food and fiber in temperate climates. Its fibers are used to create linen textiles and its oil is known as linseed oil. Flax was domesticated from the wild species Linum bienne and is grown worldwide. In New Zealand, plants called "flax" belong to the genus Phormium.

Hypericum: Hypericum is a widespread genus of flowering plants in the Hypericaceae family, found worldwide except in tropical lowlands, deserts, and polar regions. Some Hypericum species are invasive and considered as noxious weeds. They are commonly known as St. John's wort, with some also called goatweed. The marsh St. John's worts in North America and eastern Asia are grouped under the genus Triadenum Raf.

Poinsettia: The poinsettia is a flowering plant from Mexico and Central America, known for its red and green foliage. It was introduced to the US by Joel Roberts Poinsett in the 1820s. Poinsettias are commonly used in Christmas floral displays. They are not dangerous to pets or children, although consuming them may cause nausea, vomiting, or diarrhea.

Viola(plant): Viola is a large genus of flowering plants in the Violaceae family, consisting of over 680 species. The majority of these species are located in the temperate Northern Hemisphere, while others can be found in diverse regions like Hawaii, Australasia, and the Andes.

Willow: Willows, also known as sallows and osiers, are a diverse group of around 350 deciduous trees and shrubs. They are predominantly found in cold and temperate regions, thriving in moist soils.

Malvaceae: Malvaceae, or the mallows, is a family of flowering plants with around 244 genera and over 4,225 known species. Notable members include economically important plants like okra, cotton, cacao, roselle, and durian. Some genera, such as Alcea, Malva, and Tilia, contain popular ornamentals. Hibiscus, Pavonia, Sida, Ayenia, Dombeya, and Sterculia are among the genera with the highest numbers of species.

Adansonia: Adansonia is a genus of eight baobab tree species native to Madagascar, Africa, and Australia. They are known for their longevity and large, short-lived flowers that bloom rapidly at dusk. The baobab's fruits are large, oval to round, and contain kidney-shaped seeds encased in a dry, pulpy matrix. The trees are also called "upside-down trees" due to myths surrounding their unique appearance.

Henna: Henna is a dye made from the plant Lawsonia inermis. It is derived from the henna tree, also known as mignonette tree and Egyptian privet. Henna is one of the two species in the Lawsonia genus, the other being Lawsonia odorata.

Melastomataceae: Melastomataceae is a diverse family of flowering plants with over 175 genera and 5115 known species. Found in the tropics, they include annual or perennial herbs, shrubs, and small trees.

Myrtaceae: Myrtaceae is a family of dicotyledonous plants in the order Myrtales. Notable members include myrtle, pōhutukawa, bay rum tree, clove, guava, acca (feijoa), allspice, and eucalyptus. All species in this family are woody, have essential oils, and their flower parts come in multiples of four or five. The leaves are evergreen, simple, and usually alternate or mostly opposite. The flowers have five petals, but some genera have minute or absent petals. The stamens are numerous, brightly colored, and noticeable.

Eucalyptus: Eucalyptus is a large genus of over 700 flowering plants in the family Myrtaceae. Most are trees or shrubs known as eucalypts. They have distinct bark, oil glands in their leaves, and unique fruit capsules called "gumnuts". Eucalyptus is part of a tribe that includes Corymbia and Angophora.

Proteaceae: Proteaceae is a family of flowering plants found mainly in the Southern Hemisphere. It consists of 83 genera and around 1,660 known species. Australia and South Africa have the highest diversity of these plants. The family is part of the order Proteales, along with Platanaceae, Nelumbonaceae, and Sabiaceae. Well-known genera within Proteaceae include Protea, Banksia, Embothrium, Grevillea, Hakea, and Macadamia. Some popular cut flowers from this family include the New South Wales waratah, king protea, and various Banksia, Grevillea, and Leucadendron species. Macadamia nuts are widely cultivated and consumed, along with the lesser-known Gevuina avellana nuts.

Nelumbo: Nelumbo is a genus of aquatic plants with large, showy flowers, commonly called lotus. Although they resemble plants in the Nymphaeaceae family, Nelumbo is actually unrelated.

Platanus: Platanus is a small genus of trees native to the Northern Hemisphere. It is the only living member of the Platanaceae family.

Cannabis: Cannabis is a flowering plant in the Cannabaceae family and its genus includes species like Cannabis sativa, C. indica, and C. ruderalis. The number of species is debated, but they are often treated as subspecies or variations of C. sativa. Cannabis is believed to originate from Asia and is well-known for its psychoactive properties.

Moraceae: The Moraceae, also known as the mulberry family or fig family, consists of over 1100 species belonging to about 38 genera. They are mainly found in tropical and subtropical regions but can be found worldwide. The family's key characteristic is the presence of laticifers and milky sap in all parenchymatous tissues. Other notable features include inconspicuous compound flowers and fruits. Well-known examples within the family include figs, banyans, breadfruit, jackfruit, mulberries, and Osage oranges. Pseudanthia, or false flowers, are common among Moraceae.

Ficus sycomorus: Ficus sycomorus is a cultivated fig species, also known as the sycamore fig. It has been grown since ancient times.

Rosaceae: Rosaceae, or the rose family, comprises 4,828 species in 91 genera. It is a medium-sized family of flowering plants.

Rose: A rose is a perennial flowering plant that belongs to the genus Rosa in the family Rosaceae. It can be either a woody shrub or a climbing/trailing plant, armed with prickles. There are over 300 species and numerous cultivars, with flowers varying in size, shape, and color. Most species are native to Asia, while some are found in Europe, North America, and northwestern Africa. Roses are valued for their beauty, fragrance, and cultural significance. They range in size from miniature to tall climbers and are often used for hybridization in creating garden roses.

Elm: Elms are deciduous trees in the Ulmaceae family found in the Northern Hemisphere. They are distributed across temperate and tropical-montane regions of North America and Eurasia, stretching down to the Middle East, Lebanon, and Israel. They also extend across the Equator into Indonesia.

Maple: Maple is a genus of trees and shrubs, belonging to the soapberry family. There are around 132 species, mostly found in Asia, with some in Europe, Africa, and North America. The sycamore maple is the common species in Europe. The distinguishing features of maples are palmate leaves and winged fruits. They are closely related to horse chestnuts. Maple syrup is extracted from the sap of certain species, and they are widely grown for their autumn color in gardens.

Mahogany: Mahogany is a reddish-brown timber from three tropical hardwood species. It is prized for its durability and coloring, making it widely used for various products. Originally native to the Americas, it has also been cultivated in Asia and Oceania. The mahogany trade dates back to the 16th century and thrived in the 17th and 18th centuries. In some places, it is considered an invasive species.

Convolvulaceae: The Convolvulaceae family, called bindweeds or morning glories, consists of over 1,650 species across 60 genera. They are mainly herbaceous vines, but also include trees, shrubs, and herbs. Notably, some species have edible tubers, with the sweet potato being the most well-known.

Apple: An apple is a round, edible fruit that grows on apple trees, which are widely cultivated worldwide. It originated in Central Asia and has a wild ancestor still found there. Apples have been grown for thousands of years in Asia, Europe, and North America. They hold religious and mythological importance in various cultures, including Norse, Greek, and European Christian traditions.

Pear: Pears are globally grown and popular fruits harvested in late summer to mid-autumn. They come from the pear tree, a species in the Pyrus genus of the Rosaceae family. Known for their delicious edible fruit and juices, some pear species are also cultivated as trees.

Apricot: An apricot is a fruit from the Prunus genus, known for its delicious taste and associations with several species of trees.

Cherry: A cherry is a fleshy drupe fruit from the genus Prunus.

Lychee: Lychee is a fruit belonging to the soapberry family. It is the only species in the Litchi genus.

Mango: The mango is an edible stone fruit grown from a tropical tree called Mangifera indica. It originated from the region between northwestern Myanmar, Bangladesh, and northeastern India. The cultivation of mangoes dates back to ancient times in South and Southeast Asia, resulting in two main types of modern cultivars: the "Indian type" and the "Southeast Asian type." Additionally, other species within the Mangifera genus also produce edible fruits known as mangoes, most of which are found in the Malesian ecoregion.

Peach: The peach is a tree originally from Eastern China, known for producing juicy and edible fruits called peaches. It is cultivated in Zhejiang province and also yields nectarines, a similar fruit with slight differences in appearance and taste.

Plum: Plums are fruits of the Prunus subg. Prunus species. They can be dried and known as prunes, but in the US they are sometimes labeled as 'dried plums'.

Blackberry: A blackberry is an edible fruit found across various species in the genus Rubus within the Rosaceae family. The taxonomy of blackberries has been historically complicated due to hybridization and apomixis, leading to species aggregates. For instance, the subgenus Rubus is often referred to as the Rubus fruticosus aggregate, despite R. fruticosus being synonymous with R. plicatus.

Blackcurrant: Blackcurrant, also called cassis, is a shrub with edible berries. It grows in temperate regions of Europe and Asia, favoring damp fertile soils. The plant is widely cultivated for commercial and domestic use.

Blueberry: Blueberries are perennial flowering plants with blue or purple berries. They belong to the Vaccinium genus alongside cranberries, bilberries, huckleberries, and Madeira blueberries. Native to North America, commercial varieties of blueberries are widely distributed and include both wild and cultivated species. Highbush blueberries were introduced into Europe in the 1930s.

Cranberry: Cranberries are evergreen shrubs or trailing vines. In Britain, they refer to Vaccinium oxycoccos, while in North America, they refer to Vaccinium macrocarpon. The former is cultivated in Europe, while the latter is cultivated in the United States, Canada, and Chile. Oxycoccus is sometimes considered its own genus. Cranberries thrive in acidic bogs in cooler regions of the Northern Hemisphere.

Grape: Grapes are berries from Vitis vines, known for growing in clusters. They are non-climacteric fruits.

Kiwifruit: Kiwifruit, also known as Chinese gooseberry, is a berry that comes from woody vines in the Actinidia genus. The most common variety is oval-shaped, similar in size to a hen's egg. It has a thin, fuzzy, tart but edible light brown skin, and light green or golden flesh with tiny black seeds. The fruit has a soft texture and a distinct sweet flavor.

Raspberry: Raspberries are edible fruits from various plants in the Rubus genus, mostly in the subgenus Idaeobatus. They are perennial with woody stems.

Strawberry: The garden strawberry is a popular fruit known for its aroma, bright red color, juicy texture, and sweetness. It is widely cultivated worldwide and consumed fresh or in various prepared foods like jam, pies, and ice cream. Artificial strawberry flavorings are also commonly used in candies, soaps, and perfumes.

Citrus: Citrus is a genus of flowering trees and shrubs that produce citrus fruits, including oranges, lemons, grapefruits, pomelos, and limes. Native to South Asia, East Asia, Southeast Asia, Melanesia, and Australia, citrus species have been cultivated and used by indigenous cultures for thousands of years. They were later spread to Micronesia, Polynesia, the Middle East, the Mediterranean, Europe, and the Americas through trade routes and expansions.

Grapefruit: The grapefruit is a citrus tree with large, sour to semi-sweet fruit. Its segmented flesh ranges in color from pale yellow to dark pink/red.

Kumquat: Kumquats, also known as cumquats in Australian English, are small fruit-bearing trees in the Rutaceae family. Their classification has been disputed, previously considered part of the Fortunella genus or within the broader Citrus classification. Recent genomic analysis identifies three pure species: Citrus hindsii, C. margarita, and C. crassifolia, with C. x japonica being a hybrid of the last two.

Lemon: The lemon is a small evergreen tree, belonging to the Rutaceae family. It is native to Asia, particularly Northeast India, Northern Myanmar, and China.

Lime (fruit): A lime is a citrus fruit known for its acidic juice and round, green appearance. It is typically 3-6 centimeters in diameter, packed with juice vesicles.

Orange (fruit): An orange is a sweet citrus fruit from the Rutaceae family, primarily referred to as Citrus × sinensis. It is distinct from the bitter orange, known as Citrus × aurantium.

Mandarin orange: The mandarin orange is a small citrus fruit, often eaten plain or in fruit salads. It is part of a distinct species of orange and is also known as mandarin or mandarine. Tangerines are a group of orange-colored citrus fruits that are hybrids of mandarin oranges with some pomelo contribution.

Cucumis melo: 'Cucumis melo', commonly known as melon, is a cultivated fruit with various varieties. It is a pepo with either sweet or bland flesh, occasionally with a musky aroma. The rind can be smooth, ribbed, wrinkled, or netted. In North America, the sweet-flesh varieties are collectively called muskmelon, which includes the musky netted-rind and inodorous smooth-rind types. The term 'cantaloupe' generally refers to the musky netted-rind type, while the European cantaloupe has ribbed and often warty rind that is less common in North America.

Watermelon: Watermelon, a flowering plant of the Cucurbitaceae family, produces an edible fruit. It is a globally popular and extensively grown fruit with over 1,000 varieties.

Banana: A banana is an elongated, edible fruit produced by herbaceous plants in the Musa genus. It is typically curved and varies in size, color, and firmness. Bananas used for cooking are called "plantains." They grow in clusters near the top of the plant and come in different colors when ripe. Most modern edible bananas come from two wild species. The scientific names for cultivated bananas depend on their genomic constitution. The old scientific name, Musa sapientum, is no longer used.

Cooking banana: Cooking bananas are starchy fruits used in cooking that can be eaten ripe or unripe. They are often called plantains or green bananas, with true plantains belonging to the AAB group and other starchy varieties referred to as cooking bananas. These cultivars fall into the AAB, AAA, ABB, or BBB groups under the scientific name Musa × paradisiaca. Fe'i bananas, known as "mountain plantains," are consumed roasted or boiled but do not originate from the species that modern banana cultivars descend from.

Coconut: The coconut is a drupe and the only living species in its genus. It is part of the palm tree family and has three indentations on its shell, resembling a head. Coconuts are found in coastal tropical regions and are seen as a cultural symbol of the tropics.

Durian: Durian is an edible fruit of the Durio tree genus, with 30 recognized species and at least nine producing edible fruit. Durio zibethinus is the only species available internationally, while other species are sold locally. It has numerous named varieties in Thailand and Malaysia.

Fig: The fig is a fruit that grows on a small tree called Ficus carica. It is native to the Mediterranean region and parts of Asia. The tree has been cultivated for thousands of years and is now grown worldwide. Ficus carica is the main species in a genus that includes over 800 tropical and subtropical plants.

Guava: Guava is a tropical fruit widely grown in many tropical and subtropical regions. It belongs to the myrtle family and is native to Mexico, Central America, the Caribbean, and northern South America. In addition to the common guava, there are other species like strawberry guava and pineapple guava. India is the top producer, accounting for 45% of the global production in 2019. Botanically, guavas are classified as berries.

Jackfruit: The jackfruit is a large fruit from the jack tree, belonging to the fig, mulberry, and breadfruit family. It can grow up to 55 kg, 90 cm long, and 50 cm in diameter. A mature jackfruit tree produces around 200 fruits annually, with some older trees yielding up to 500 fruits. This fruit is a combination of many flowers, and its unripe fleshy petals are edible.

Papaya: The papaya is a tropical plant native to Mesoamerica and belonging to the Caricaceae family. It is cultivated in various countries with tropical climates. In 2020, India accounted for 42% of the global papaya production.

Pineapple: The pineapple is a tropical plant in the family Bromeliaceae, known for its economically significant edible fruit.

Pomegranate: The pomegranate is a fruit-bearing deciduous shrub that grows up to 10 m tall. It is known for its rich symbolic and mythological associations in various cultures.

Tamarind: Tamarind is a tropical fruit tree found in Africa and Asia. It is the only species in its genus, Tamarindus, and belongs to the Fabaceae family.

Avocado: The avocado is a medium-sized evergreen tree native to the Americas. It was domesticated in Mesoamerica over 5,000 years ago and prized for its oily fruit. Avocado trees likely originated in the highlands of Mexico and Guatemala. The fruit is a large berry with a single seed, also known as an alligator pear or avocado pear. Avocados have a hybrid origin and their evolution was influenced by polyploidy events. They are partly self-pollinating and often propagated through grafting. Avocados are cultivated in tropical and Mediterranean climates worldwide, with Mexico being the leading producer, supplying nearly 30% of the global harvest in 2020.

Date palm: The date palm, scientifically known as Phoenix dactylifera, is a popular plant cultivated for its sweet edible fruit called dates. It belongs to the palm family and is widely grown in northern Africa, the Middle East, and South Asia, with naturalized populations found in tropical and subtropical regions globally. P. dactylifera is the main species among the 12-19 wild date palm varieties found in the genus Phoenix.

Morus(plant): Morus is a genus of flowering plants in the family Moraceae, including diverse deciduous trees known as mulberries. There are three well-known species: white, red, and black mulberry, with various cultivars. Native to South Asia, the white mulberry is widely distributed across Europe, Southern Africa, South America, and North America. It is also favored by silkworms and considered invasive in Brazil and the United States.

Olive: The olive is a small tree or shrub found in the Mediterranean Basin, known as Olea europaea. It is also called the European olive. The species is cultivated in various countries including the Mediterranean region, Australia, New Zealand, North and South America and South Africa. The olive tree is the type species for its genus, Olea, and it belongs to the Oleaceae plant family. This family also includes other species like lilac, jasmine, forsythia, and the true ash tree.

Bell pepper: Bell peppers, classified as fruits but used as vegetables, are the diverse and colorful fruits of the Capsicum annuum plant. They come in various hues such as red, yellow, orange, green, white, chocolate, candy cane striped, and purple. Often referred to as "sweet peppers," they are distinct from pungent chili peppers. Cultivated primarily for their mild flavor, they make a frequent appearance in savory dishes and are known for their versatility.

Breadfruit: Breadfruit is a flowering tree believed to have originated in New Guinea, the Maluku Islands, and the Philippines. It was brought to Oceania during the Austronesian expansion and later spread to other tropical regions during the Colonial Era. British and French navigators introduced seedless varieties to the Caribbean in the late 18th century. Today, it is grown in 90 countries across South and Southeast Asia, the Pacific Ocean, the Caribbean, Central America, and Africa. The fruit's name comes from its texture after cooking, resembling freshly baked bread and having a potato-like taste.

Chili pepper: Chili peppers are spicy berry-fruits from the Capsicum genus, used in various cuisines worldwide. They belong to the nightshade family and are known for their pungency. Capsaicin and capsaicinoids provide the intense flavor when consumed or applied topically. Chili peppers offer a diverse range of heat and flavors, leading to the creation of different paprika and chili powder varieties with distinctive tastes and spice levels.

Cucumber: A cucumber is a crawling vine plant that produces cylindrical or spherical fruits used for cooking. It is cultivated worldwide and classified into three main types: slicing, pickling, and seedless, with numerous varieties within each type. Originally from Asia, it now grows on most continents and is commercially traded globally. In North America, the term "wild cucumber" refers to unrelated plants in the genera Echinocystis and Marah.

Cucurbita: Cucurbita is a genus of herbaceous fruits, native to the Andes and Mesoamerica. Five edible species are cultivated for their flesh and seeds, known as squash, pumpkin, or gourd depending on species. Cucurbita belongs to the gourd family.

Zucchini: Zucchini, also known as courgette or baby marrow, is a type of summer squash. It comes from a vining plant, and its fruits are picked when the seeds and rind are still tender and edible. Although similar to marrow, zucchini is distinct and has mature fruits known as marrow.

Pumpkin: A pumpkin is a type of winter squash in the genus Cucurbita, commonly characterized by its round shape and orange color. While lacking a scientific definition, the term "pumpkin" is often used to refer to various squashes with different appearances.

Eggplant: Eggplant, also known as aubergine, brinjal, or baigan (GY), is a widely cultivated plant in the nightshade family Solanaceae. Its scientific name is Solanum melongena. This plant is primarily grown for its edible fruit, which is enjoyed worldwide.

Green bean: Green beans are the young, unripe fruits of several bean cultivars. They are also called French beans, string beans, or snap beans. They can be used similarly to immature pods of runner beans, yardlong beans, and hyacinth beans. In the Philippines, they are known as "Baguio beans" or "habichuelas" to differentiate them from yardlong beans.

Okra: Okra, or Abelmoschus esculentus, is a flowering plant native to East Africa. It is also known as lady's fingers. The plant produces edible green seed pods. Okra is cultivated in tropical, subtropical, and warm temperate regions worldwide and is used in the cuisines of multiple countries.

Tomato: The tomato is an edible berry from the tomato plant. It originated in South America and was domesticated by indigenous peoples in Mexico. The Aztecs used tomatoes in their cooking, and the Spanish brought the plant to Europe during the Columbian exchange. The tomato was then introduced to other parts of the European-colonized world during the 16th century.

Barley: Barley is a cereal grain that belongs to the grass family and is grown in temperate climates worldwide. It was one of the first cultivated grains and was domesticated around 9,000 BC, making harvesting easier. Barley spread throughout Eurasia by 2,000 BC. It thrives in cooler temperatures and well-drained soil, while also being relatively resilient to drought and soil salinity. However, it is less winter-hardy compared to wheat or rye.

Maize: Maize, commonly known as corn, is a tall grass that produces cereal grain. It was domesticated in southern Mexico 9,000 years ago. Native Americans cultivated it in the Three Sisters polyculture with beans and squashes. Maize has male tassels that produce pollen and female ears that yield kernels. Modern varieties are usually yellow or white, but other colors exist.

Millet: Millets are small-seeded grasses cultivated globally as cereal crops and for fodder and human consumption. They belong to the tribe Paniceae, although some millets are part of other taxa.

Oat: Oats, a common cereal grain, are valued for their seeds known by the same name. They are consumed as oatmeal and rolled oats, rich in nutrients and linked to lower cholesterol and decreased heart disease risk. Oats are also widely utilized as livestock feed.

Rice: Rice is a cereal grain that is the main food source for over half of the world's population, predominantly in Asia and Africa. It originated in China and Africa thousands of years ago. In 2021, 787 million tons of rice were produced, making it the fourth most cultivated crop globally. China, India, and Indonesia are the largest rice consumers. Losses occur after harvest due to poor transportation and storage. Pests, diseases, and weeds can harm rice yields, but sustainable practices like rice-duck farming and integrated pest management help manage these issues.

Oryza sativa: Oryza sativa, commonly known as rice, is a globally prevalent crop. It originated in China around 13,500 to 8,200 years ago in the Yangtze River basin.

Rye: Rye is a versatile grain that is cultivated as a grain, cover crop, and forage crop. It belongs to the wheat tribe and shares similarities with wheat and barley. Rye grain is used to make flour, bread, beer, crispbread, whiskeys, and vodkas, while also serving as fodder for animals. It can be consumed whole, either boiled or rolled like oats.

Sorghum: Sorghum, a genus of flowering plants in the grass family, includes around 25 species. Some are cultivated as cereals or animal fodder, while others provide bristles for brooms. Sorghum grain is highly nutritious, containing protein, dietary fiber, B vitamins, and minerals such as.

Wheat: Wheat is a widely cultivated grass known for its cereal grain, which is a common staple food worldwide. It belongs to the genus Triticum, with common wheat being the most popular species. Archaeological evidence points to its cultivation beginning around 9600 BC in the Fertile Crescent region. Botanically, the wheat kernel is classified as a caryopsis, a type of fruit.

Common wheat: Common wheat, also known as bread wheat, is a highly cultivated wheat species that accounts for 95% of global wheat production. It is the most extensively grown crop and has the highest monetary yield among cereals.

Amaranth: Amaranth is a diverse genus of plants that includes both annual and perennial varieties. It is cultivated for its edible leaves, seeds, and for ornamental use. The flowers grow densely in catkin-like clusters during summer or fall, displaying a range of vibrant colors. With over 75 species, amaranth is found across the globe, from North America to the Himalayas. The stems are tall and succulent, reaching 1 to 2.5 meters in height. Amaranth shares similarities with the related genus Celosia, and its grains are used for collection. Some species' leaves are also consumed as a food source.

Buckwheat: Buckwheat is a flowering plant grown for its grain-like seeds and as a cover crop. It belongs to the knotweed family Polygonaceae. The term 'buckwheat' is also used for other species, including Fagopyrum tataricum, a cultivated food plant primarily found in Asia.

Quinoa: Quinoa is a flowering plant grown primarily for its edible seeds, which are rich in protein, dietary fiber, B vitamins, and minerals. It is not a grass but a pseudocereal related to spinach and amaranth. Quinoa originated in the Andean region of South America and has been used for feeding livestock for thousands of years. It has been a staple food for human consumption for thousands of years as well, particularly in Peru and Bolivia.

Almond: The almond is a small tree cultivated globally for its culinary nut. It belongs to the genus Prunus and is part of the subgenus Amygdalus, distinguishable by the corrugations on its shell.

Brazil nut: The Brazil nut is a South American tree in the Lecythidaceae family. It produces large, long-lived trees and commercially harvested edible seeds. The Brazil nut is notable for its high selenium content and diverse micronutrients. The tree's wood is valued for its quality in various carpentry and construction applications.

Cashew: The cashew is a tropical tree from South America that produces cashew seeds and apples. It can grow up to 14 meters tall but dwarf cultivars are more profitable. The seed is a snack nut and can be used in recipes, processed into cashew cheese or butter. Cashew allergies are caused by proteins in tree nuts and cooking doesn't remove them.

Chestnut: Chestnuts are deciduous trees and shrubs in the Castanea genus, known for producing edible nuts. They belong to the beech family and are found in temperate regions of the Northern Hemisphere.

Hazelnut: The hazelnut, derived from the hazel tree, refers to any nuts from the Corylus genus, mainly Corylus avellana. They are often called cobnuts or filberts, depending on the species.

Macadamia: Macadamia is a genus of four trees native to Australia, with two species commercially important for their fruit, the macadamia nut. Also known as Queensland nut or bush nut, they were a significant food source for Aboriginal peoples. Global production in 2015 reached 160,000 tonnes.

Pecan: The pecan is a type of hickory tree found in the southern US and northern Mexico near the Mississippi River.

Walnut: A walnut is the edible seed of a tree from the genus Juglans, like the Persian or English walnut. It is a drupe-like nut, with an outer covering that is not part of the carpel.

Bean: Beans are seeds from the Fabaceae family, commonly eaten worldwide. They're versatile and can be cooked through boiling, frying, or baking. Used as vegetables for both human and animal food, beans are essential ingredients in various traditional dishes.

Lentil: The lentil is an edible legume with lens-shaped seeds. It is an annual plant that grows about 40 cm tall and produces pods containing two seeds each. Canada and India are the top global producers of lentils, accounting for 29% and 27% of the world's total lentil production in 2021.

Lima bean: The Lima bean, also called butter bean or sieva bean, is a legume known for its edible seeds. It is commonly grown for its beans.

Phaseolus vulgaris: Phaseolus vulgaris, commonly known as the common bean, is a versatile annual plant cultivated globally for its edible dry seeds and green pods. It is also used for its leaf as a vegetable and straw as fodder. Belonging to the Fabaceae family, like other Phaseolus species, common beans have a symbiotic relationship with nitrogen-fixing bacteria called rhizobia, enabling them to obtain the necessary nitrogen.

Soybean: The soybean, also known as soy or soya, is a legume native to East Asia. It is extensively cultivated for its versatile and edible beans that serve various purposes.

Vicia faba: Vicia faba, commonly known as broad bean or fava bean, is a flowering plant cultivated as a crop for human consumption and as a cover crop. It belongs to the pea and bean family Fabaceae. This legume is widely grown in Southern European, Northern European, East Asian, Latin American, and North African cuisines. It has smaller, harder seeds that are sometimes used as feed for horses and other animals, known as field bean or tic bean. The horse bean, a variety of Vicia faba, is recognized as an accepted name.

Chickpea: The chickpea, an annual legume, belongs to the family Fabaceae and is known by different names. Its seeds are rich in protein and it is one of the oldest cultivated legumes, with archaeological evidence found in Syria.

Pea: Pea is a versatile plant species that can be consumed as a pulse, vegetable, or fodder crop. It mainly refers to the seed or pod of the plant, formerly known as Pisum sativum and now renamed Lathyrus oleraceus. Pea pods are technically fruit, as they develop from the ovary of a pea flower and contain multiple seeds (peas). The term "pea" is also used for other edible seeds from the Fabaceae family, such as pigeon peas and cowpeas. Additionally, it can be used as a compound form, like Sturt's desert pea.

Peanut: The peanut, also known as the groundnut, is a legume crop grown for its edible seeds. It is widely cultivated in the tropics and subtropics for small and large commercial purposes. With its high oil content, peanuts are classified as both a grain legume and an oil crop. China leads global production, accounting for 38% of shelled peanuts in 2016. Unlike most legumes, peanut pods grow underground, leading to its specific epithet "hypogaea" meaning "under the earth."

Cabbage: Cabbage is a leafy green or purple vegetable, grown as an annual crop for its dense heads. It is a cultivar of Brassica oleracea and belongs to the "cole crops" group, closely related to broccoli, cauliflower, Brussels sprouts, and Savoy cabbage.

Chard: Chard, also known as Swiss chard, is a leafy vegetable with large stalks and separate leaf blades. It belongs to the Flavescens Group, where stalks are commonly prepared separately. The Cicla Group refers to leafy spinach beet. Chard has green or reddish blades and white, yellow or red stalks.

Chinese cabbage: Chinese cabbage refers to two cultivar groups of leaf vegetables commonly used in Chinese cuisine: the Pekinensis Group and the Chinensis Group.

Collard (plant): Collard is a loose-leafed cultivar of Brassica oleracea, belonging to the same species as cabbage and broccoli. It is categorized under the Acephala cultivar group and has its own variety called Brassica oleracea var. viridis. "Collard" originates from the term "colewort."

Eruca vesicaria: Eruca vesicaria, also known as rocket or arugula, is an annual plant in the Brassicaceae family. It is used as a leaf vegetable and is valued for its fresh, tart, bitter, and peppery taste. This plant, native to the Mediterranean region, is commonly referred to as "garden rocket" and has various other names like "colewort," "roquette," "ruchetta," "rucola," "rucoli," and "rugula." It is highly popular as a salad vegetable.

Kale: Kale, known as leaf cabbage, is a group of cabbage varieties cultivated for its edible leaves. Some are grown for ornamental purposes. Kale plants have green or purple non-head-forming leaves. They are closer to wild cabbage and are derived from wild mustard.

Lettuce: Lettuce is a leafy vegetable from the Asteraceae family. It is commonly used in salads and other dishes like soups, sandwiches, wraps, and grilled preparations. Some varieties, like celtuce, are grown for their edible stems. Lettuce holds cultural, culinary, and medicinal significance globally. Originally popular in Europe and North America, lettuce consumption has now spread worldwide. In 2021, lettuce and chicory production reached 27 million tonnes, with China accounting for 53 percent of the total.

Rapeseed: Rapeseed, or oilseed rape, is a yellow-flowering plant cultivated for its oil-rich seed containing erucic acid. Canola refers to low erucic acid rapeseed varieties prized for food use. Rapeseed is a major source of vegetable oil and protein meal globally.

Spinach: Spinach is a leafy green plant found in central and Western Asia, commonly used as a vegetable. It can be eaten fresh or preserved through canning, freezing, or dehydration. The taste varies, and it can be consumed cooked or raw. Steaming helps reduce its high oxalate content.

Arrowroot: Arrowroot is a tropical plant starch derived from rhizomes like Maranta arundinacea, Zamia integrifolia, and cassava. It is also known as tapioca or labeled as arrowroot. Polynesian arrowroot (pia) and Japanese arrowroot (kudzu) have similar uses. In India, it is called palua.

Beetroot: The beetroot, or beets, is a taproot vegetable known by different names in North America and British English. It is also called table beet, garden beet, red beet, dinner beet or golden beet.

Carrot: The carrot is a root vegetable that is typically orange in color, but can also be purple, black, red, white, or yellow. It is a domesticated form of the wild carrot, native to Europe and Southwestern Asia. Carrots were originally cultivated for their leaves and seeds. The most commonly consumed part is the taproot, which has been selectively bred to be larger, tastier, and less woody-textured.

Cassava: Cassava, also known as manioc or yuca, is a woody shrub native to South America. It is cultivated as an annual crop in tropical regions for its starchy root tuber, which is a major source of carbohydrates. Cassava is boiled and eaten, but also used to extract tapioca starch for food, animal feed, and industrial purposes. Farinha in Brazil and garri in West Africa are edible flours made from grated, dried cassava pulp.

Onion: The onion is a widely cultivated vegetable and the main species in the Allium genus. It is also known as the bulb onion or common onion. The shallot is a variety of onion that was considered a separate species until 2011. It is closely related to garlic, scallion, leek, and chive.

Parsnip: The parsnip is a root vegetable closely related to carrot and parsley. It has a cream-colored skin and flesh with a long taproot. It is usually grown as an annual but is biennial. The plant has green leaves in the first year and produces small yellow flowers in the second year. The stem becomes woody and the tap root inedible. Handling the stems and foliage can cause a skin rash or blindness if exposed to sunlight.

Potato: The potato is a starchy vegetable consumed worldwide as a staple food. It is a tuber of the Solanum tuberosum plant, belonging to the Solanaceae family.

Radish: The radish is an edible root vegetable domesticated in Asia before Roman times, belonging to the mustard family.

Daikon: Daikon, also known as mooli, is a winter radish with fast-growing leaves and a long, white, napiform root. Native to East Asia, it is widely consumed in the region, including South Asia, and is available worldwide. It is also planted in certain areas to improve soil quality and nutrient recovery.

Rutabaga: Rutabaga, also known as swede or Swedish turnip, is a root vegetable belonging to the Brassica napus species. The roots are consumed as food and can be prepared in various ways, while the leaves can be eaten as a leafy vegetable. Rutabaga is distinct from the white turnip, and it originated as a hybrid between cabbage and turnip. It is commonly utilized as livestock feed during winter or foraged in the field throughout other seasons. Moreover, carving rutabaga roots into Jack-o'-lanterns on Halloween is a tradition in Scotland, Northern and Western England, Wales, the Isle of Man, and Ireland.

Sugar beet: A sugar beet is a commercially grown plant with a high sucrose content in its root. It is part of the Altissima cultivar group of the common beet, classified as var. saccharifera. Its closest wild relative is the sea beet.

Sweet potato: The sweet potato is a plant with starchy, sweet-tasting tuberous roots that are used as a root vegetable. It belongs to the Convolvulaceae family and is not closely related to common potatoes. The plant produces cultivars with tubers of different colors, and its young shoots and leaves can also be eaten. Despite the name, sweet potatoes are not true yams, which are a different plant species.

Taro: Taro is a widely grown root vegetable, used for its corms, leaves, stems and petioles. It serves as a food staple in diverse cultures, including African, Oceanic, East Asian, Southeast Asian, and South Asian. Considered one of the earliest cultivated plants.

Turnip: The turnip is a root vegetable with a white, fleshy taproot. It is commonly grown worldwide for human consumption and as feed for livestock. In some regions, the term "turnip" is also used to refer to rutabaga, a larger yellow root vegetable.

Yam (vegetable): Yam refers to certain edible tubers grown by plants in the Dioscorea genus.

Artichoke: The artichoke is a type of thistle that is cultivated as a food. It is also known as the globe artichoke, French artichoke, and green artichoke in the U.S.

Asparagus: Asparagus is a plant species from Eurasia, cultivated as a vegetable crop. Its young shoots are popularly consumed as a spring vegetable.

Broccoli: Broccoli is a green vegetable in the cabbage family, known for its large flower heads and thick stalk. It belongs to the Italica cultivar group of the species Brassica oleracea. The flower heads are usually dark green and arranged in a tree-like structure. Surrounding the flower heads are leaves. Although similar to cauliflower, broccoli is a different cultivar group of the same Brassica species.

Cauliflower: Cauliflower is a vegetable from the Brassica oleracea species, characterized by its annual growth and seed reproduction. It is known for its white, edible head, also called "curd," which is made up of a white inflorescence meristem. Cauliflower is a close relative of broccoli and other "cole" crops like cabbage and kale.

Celery: Celery is a vegetable in the family Apiaceae, cultivated for centuries. Its long fibrous stalks, leaves, and hypocotyl are used in cooking. The plant is found in marshlands and its seed powder is used as a spice.

Chicory: Chicory is a perennial herb with woody stems and bright blue flowers, occasionally white or pink. It belongs to the Asteraceae family and is originally from the Old World. It has been cultivated in the Americas and Australia as well.

Kohlrabi: Kohlrabi is a biennial vegetable, also known as German turnip or turnip cabbage. It is a stout cultivar of wild cabbage and belongs to the same species as broccoli, cauliflower, kale, Brussels sprouts, and other leafy greens.

Leek: The leek is a vegetable that belongs to the Allium genus, along with onions, garlic, and other related plants. It is a cultivar of Allium ampeloprasum, commonly known as the broadleaf wild leek. The edible part of the leek is a bundle of leaf sheaths, often mistaken for a stem or stalk. There are three closely related vegetables, including elephant garlic, kurrat, and Persian leek or tareh, which are also cultivars of A. ampeloprasum but differ in their culinary uses.

Anise: Anise, also known as aniseed, is a flowering plant from the Apiaceae family. It is native to the eastern Mediterranean region and Southwest Asia.

Basil: Basil, or great basil, is a tender culinary herb used worldwide. It belongs to the Lamiaceae family and is commonly known as sweet basil or Genovese basil in Western cuisine. Basil is native to tropical regions from Central Africa to Southeast Asia. While treated as an annual in temperate climates, it can be a short-lived perennial or biennial in warmer horticultural zones with tropical or Mediterranean climates.

Black pepper: Black pepper is a vine cultivated for its dried fruit, used as a spice. The fruit is small, dark red, and contains a single seed. The spice can be referred to as black pepper, green pepper, or white pepper.

Cardamom: Cardamom is a spice derived from the seeds of plants in the genera Elettaria and Amomum. It is native to India and Indonesia and is characterized by small, triangular seed pods with a thin outer shell and black seeds. Elettaria pods are light green, while Amomum pods are larger and dark brown.

Cinnamon: Cinnamon is a spice derived from the inner bark of certain trees in the Cinnamomum genus. It is widely used as a condiment and flavor enhancer in a variety of dishes and foods, including cereals, teas, and snacks. The distinctive aroma and flavor of cinnamon come from its essential oil, primarily composed of cinnamaldehyde, along with other compounds like eugenol.

Clove: Cloves are the flower buds of a tree native to Indonesia, commonly used for their aromatic properties. They serve as a spice, flavoring agent, and fragrance in consumer products like toothpaste and soaps. Cloves are accessible all year round due to their harvest seasons in different countries.

Cumin: Cumin is a flowering plant found in the Irano-Turanian Region. Its dried seeds are used in cuisines worldwide. While it has traditional medicinal use, there is no strong evidence supporting its effectiveness or safety as a therapeutic agent.

Fennel: Fennel is a flowering plant in the carrot family. It has yellow flowers and feathery leaves. Originally from the Mediterranean, it has spread to various parts of the world, thriving in dry soils near the coast and riverbanks.

Garlic: Garlic is a plant in the Allium genus, closely related to onions, leeks, and shallots. It is native to South and Central Asia, and northeastern Iran. Garlic has a long history of human consumption and is used worldwide as a seasoning. It was also used by ancient Egyptians for both culinary and medicinal purposes. China is the largest producer of garlic, accounting for 73% of the global supply in 2021.

Ginger: Ginger is a versatile plant known for its rhizome, widely used as a spice and in traditional medicine. It grows up to one meter tall with narrow leaf blades and produces pale yellow flowers with purple edges from separate shoots on the rhizome.

Ginseng: Ginseng is a root found in plants of the Panax genus, including Korean, South Chinese, and American varieties. It contains ginsenosides and gintonin. Ginseng is widely used in Chinese and Korean cuisine and medicine.

Horseradish: The horseradish is a perennial plant from the Brassicaceae family. It is a spice and condiment that is cultivated globally. Native to Southeastern Europe and Western Asia.

Lavandula: Lavandula is a plant genus in the mint family with 47 known species. It is native to the Old World and can be found in various regions, including Cape Verde, the Canary Islands, Europe, northern and eastern Africa, the Mediterranean, and southwest Asia to India.

Liquorice: Liquorice, scientifically known as Glycyrrhiza glabra, is a flowering plant that belongs to the bean family Fabaceae. It is primarily cultivated for its sweet and aromatic flavoring, which is extracted from its root.

Mentha: Mentha is a plant genus in the Lamiaceae family, containing 13 to 24 species. Natural hybridization occurs when species' ranges overlap, resulting in numerous known hybrids and cultivars.

Nutmeg: Nutmeg is a spice derived from the seed of trees of the genus Myristica. It is also the source of mace, a spice derived from the seed covering. Nutmeg is produced in Indonesia and is the main ingredient in nutmeg and mace. The tree is native to Indonesia and is also used to obtain nutmeg essential oil and nutmeg butter.

Parsley: Parsley, a flowering plant in the Apiaceae family, is native to Greece, Morocco, and the former Yugoslavia. It has been introduced and cultivated worldwide as a popular herb and vegetable.

Saffron: Saffron is a spice made from the flower of the saffron crocus. Its vivid crimson stigma and styles are collected and dried for use in food as a seasoning and colorant. Its origin is uncertain, but it is believed to have originated in Iran, with Greece and Mesopotamia also suggested. It spread throughout Eurasia and was later introduced to parts of Africa, America, and Oceania.

Thyme: Thyme is a perennial herb in the mint family, known for its aromatic properties. It belongs to the genus Thymus and is related to oregano. Thyme is native to the Mediterranean region and is commonly used in cooking, medicine, and as an ornamental plant. The most widely cultivated species is Thymus vulgaris.

Vanilla: Vanilla is a spice sourced from vanilla orchids, mainly extracted from the pods of the flat-leaved vanilla plant (V. planifolia).

Fungus: Fungi are eukaryotic microorganisms found in the same kingdom as animals, plants, and some other microorganisms. They include yeasts, molds, and mushrooms.

Mushroom: A mushroom is a fleshy fruiting body of a fungus, grown above ground or on soil/food source. "Toadstool" usually refers to a mushroom poisonous to humans.

Ascomycota: Ascomycota is a large phylum of fungi that is part of the kingdom Fungi. It forms the subkingdom Dikarya along with Basidiomycota. Ascomycota contains over 64,000 species and is known for its sac fungi or ascomycetes. The defining feature of this group is the "ascus," a microscopic structure where nonmotile spores called ascospores are formed. However, some Ascomycota species are asexual and do not form ascus or ascospores. Well-known examples of sac fungi include morels, truffles, brewers' and bakers' yeast, dead man's fingers, and cup fungi. Ascomycota fungi are also commonly found as symbionts in lichens, such as Cladonia.

Basidiomycota: Basidiomycota is a division within the kingdom Fungi that, together with Ascomycota, forms the subkingdom Dikarya. Its members, called basidiomycetes, include various groups like agarics, puffballs, bracket fungi, and more. Basidiomycota also encompasses human pathogens like Cryptococcus and is known for its diversity and ecological importance.

Lichen: Lichens are composite organisms formed from algae or cyanobacteria and multiple fungi species. They play a vital role in nutrient cycling and serve as a food source for various animals. Lichens possess unique properties and come in diverse colors, sizes, and forms, resembling plants but not being classified as such. They exhibit different growth forms such as fruticose, foliose, crustose, and leprose.

Yeast: Yeast is a single-celled microorganism belonging to the fungus kingdom. It is eukaryotic and has been around for hundreds of millions of years. There are more than 1,500 known species of yeast, making up around 1% of all described fungi.

Saccharomyces cerevisiae: Saccharomyces cerevisiae is a yeast that has been used in winemaking, baking, and brewing since ancient times. It was originally found on grape skins and is extensively studied in molecular and cell biology. S. cerevisiae is responsible for the most common form of fermentation, and its cells are round and reproduce by budding.

Zygomycota: Zygomycota, or zygote fungi, is a former division of the Fungi kingdom that is now classified under two phyla: Mucoromycota and Zoopagomycota. There are around 1060 known species, primarily found on land in soil or decaying organic matter. They can be parasites of plants, insects, and small animals, or have symbiotic relationships with plants. Zygomycota hyphae are usually coenocytic, forming septa only for gamete formation or to isolate dead hyphae. However, Zygomycota is no longer considered a valid classification since it was not believed to be monophyletic.

Agaricus: Agaricus is a diverse genus of mushroom-forming fungi, comprising over 400 known species and potentially many more disputed or newly-discovered ones. It includes both edible and poisonous mushrooms, with notable representatives being the common "button" mushroom and the field mushroom, which are widely cultivated in the Western world.

Boletus edulis: Boletus edulis is a widely distributed basidiomycete fungus, found in Europe, Asia, and North America. It has been introduced to southern Africa, Australia, New Zealand, and Brazil. Previously thought to be varieties, related European mushrooms are now recognized as distinct species. Some mushrooms once considered separate species are actually the same as B. edulis. The California king bolete, identified in 2007, is a larger and darker variant found in western North America.

Chanterelle: Chanterelle is a type of fungi found in various genera. They are popular edible mushrooms, with orange, yellow, or white colors and a funnel-like shape. Most species have forked folds underneath the cap, emitting a fruity aroma similar to apricots. The name "chanterelle" comes from the Greek word for "tankard" or "cup," referencing their shape.

Pleurotus ostreatus: Pleurotus ostreatus, also known as oyster mushroom, is a popular edible fungus. It is commonly found in the wild but can also be cultivated on straw and other materials.

Shiitake: The shiitake mushroom is a widely cultivated and consumed edible fungus originating from East Asia. It is valued for its medicinal properties in traditional medicine.

Truffle: Truffles are subterranean fungi, specifically the fruiting bodies of the Tuber genus and other genera like Geopora and Peziza. They belong to the Pezizomycetes class and Pezizales order. Typically found near tree roots, truffles play ecological roles in nutrient cycling and drought tolerance. Spores are spread by animals that consume fungi.

Amanita muscaria: Amanita muscaria, also called fly agaric or fly amanita, is a large red mushroom with white spots. It belongs to the Amanita genus of basidiomycetes and has white gills.

Amanita phalloides: Amanita phalloides, also known as the death cap, is a deadly poisonous fungus found in Europe. It forms symbiotic relationships with various broadleaved trees. The death cap has spread to other parts of the world through the cultivation of non-native tree species. Its mushrooms, which appear in summer and autumn, have greenish caps and white stipes and gills. The cap color varies, making it an unreliable identifier.

Plankton: Plankton are aquatic organisms that cannot move against a current. They are an important food source for various marine animals like fish and whales.

Prokaryote: A prokaryote is a single-cell organism without a nucleus or other membrane-bound organelles, derived from the Greek words for "before" and "nut." In the two-empire system, prokaryotes were part of the Prokaryota empire, but in the three-domain system, they are split into Bacteria and Archaea. Eukaryotes with nuclei are placed in the third domain, Eukaryota.

Archaea: Archaea is a domain of single-celled microorganisms that lack cell nuclei, making them prokaryotes. Initially considered bacteria, they were called archaebacteria but this term is no longer used.

Bacteria: Bacteria are single-celled organisms that are found everywhere on Earth. They were among the first life forms and can survive in various environments. Bacteria play a vital role in recycling nutrients and fixing nitrogen. They decompose dead bodies and provide nutrients in extreme environments. Bacteria can live in relationships with plants and animals. Many species of bacteria remain uncharacterized and cannot be grown in a lab. Bacteriology is the study of bacteria.

Cyanobacteria: Cyanobacteria, also known as Cyanobacteriota or Cyanophyta, are gram-negative bacteria that perform photosynthesis for energy. Despite being called blue-green algae, they are not commonly classified as algae. Originating in freshwater or terrestrial environments, cyanobacteria produce cyanotoxins that can have harmful effects on human and animal health.

Escherichia coli: Escherichia coli is a common bacterium found in the lower intestine of warm-blooded organisms. Most strains are harmless or even beneficial, producing vitamin K2 and preventing the colonization of pathogenic bacteria. However, some strains can cause serious food poisoning and prompt product recalls. E. coli is expelled in fecal matter and grows rapidly in fresh feces but its numbers decline over time.

Salmonella: Salmonella is a group of bacteria that are rod-shaped and gram-negative. It belongs to the Enterobacteriaceae family and includes two known species: Salmonella enterica and Salmonella bongori. S. enterica has six subspecies, with over 2,600 serotypes. This bacteria was named after Daniel Elmer Salmon, an American veterinary surgeon.

Staphylococcus aureus: Staphylococcus aureus is a Gram-positive bacterium commonly found in the human microbiota, residing in the upper respiratory tract and on the skin. It can act as a harmless member of the body's bacteria but can also become a dangerous pathogen causing skin infections, respiratory issues, and food poisoning. The bacterium has the ability to survive without oxygen and produces virulence factors that aid in infection. It is a major contributor to deaths related to antimicrobial resistance, especially methicillin-resistant S. aureus (MRSA). Despite efforts, there is currently no approved vaccine for S. aureus.

Eukaryote: Eukaryotes are organisms with cells that contain a nucleus surrounded by a membrane. They include animals, plants, fungi, and many unicellular organisms. Eukaryotes are a major group of life forms, outnumbered by prokaryotes but having a larger global biomass due to their larger size.

Algae: Algae refers to a diverse group of photosynthetic organisms that range from unicellular microalgae to large multicellular forms like seaweeds. They can be found in various aquatic habitats and do not possess some specialized structures present in land plants. Phytoplankton, including microalgae, are considered as waterborne algae.

Seaweed: Seaweed is a group of marine algae comprising various species categorized into red, brown, and green macroalgae. Some seaweed types, like kelps, serve as vital habitats for marine creatures, safeguarding their food sources. Additionally, certain types of seaweed, including planktonic algae, play a crucial role in capturing carbon and generating more than half of the Earth's oxygen.

Protist: Protists are eukaryotic organisms that do not belong to the animal, plant, or fungus kingdoms. They form an artificial grouping of different clades that evolved from a common ancestor.

Slime mold: Slime mold, a group of unrelated eukaryotic organisms, includes microscopic species as well as larger plasmodial slime molds visible to the naked eye. Their life cycle involves a single-celled stage and spore formation. Fruiting bodies, formed through aggregation or fusion, produce spores. Slime molds aid in decomposing dead vegetation and some even exhibit parasitic behavior.

Amoebozoa: Amoebozoa is a taxonomic group with about 2,400 known species of amoeboid protists. They have lobose pseudopods and tubular mitochondrial cristae. It is considered a phylum in Protista or Protozoa, but also an unranked "supergroup" in Eukaryota. Molecular genetic analysis confirms it as a monophyletic clade. Amoebozoa is closely related to Opisthokonta, which includes fungi and animals. They are sometimes grouped as Unikonta, Amorphea, or Opimoda.

Chromalveolata: Chromalveolata was a eukaryotic supergroup, considered one of the six major groups within eukaryotes. It emerged from a refinement of the kingdom Chromista proposed in 1981. Chromalveolata represented organisms resulting from a specific type of endosymbiosis involving a red alga and a bikont organism. These organisms possessed plastids containing chlorophyll c.

Stramenopile: Stramenopiles, or Heterokonts, are organisms with stiff tripartite external hairs. The hairs are usually attached to flagella or other parts of the cellular surface. They are part of the SAR supergroup, along with Alveolata and Rhizaria.

Brown algae: Brown algae are a type of multicellular algae found in colder waters of the Northern Hemisphere. They are major seaweeds in temperate and polar regions, often growing along rocky seashores. These algae play a vital role in marine ecosystems as a food source and habitat for various species. Notably, kelp forests formed by species like Macrocystis can reach impressive lengths and support diverse marine life. Sargassum also creates floating mats in the Sargasso Sea, serving as habitats for many species. Some brown algae, like kelps, are even consumed by humans.

Kelp: Kelp is a type of large brown seaweed, not a plant but a stramenopile. It belongs to the order Laminariales and encompasses approximately 30 different genera.

Diatom: Diatoms are a type of algae found in oceans, waterways, and soils worldwide. They contribute significantly to Earth's biomass, producing 20-50% of the planet's oxygen and absorbing billions of tons of silicon annually. Dead diatoms form deep ocean floor layers, while their shells transport nutrients to the Amazon basin from the African Sahara.

Haptophyte: Haptophytes, also known as Haptophyta or Prymnesiophyta, are a group of algae.

Cryptomonad: Cryptomonads are algae that are found in freshwater, as well as marine and brackish habitats. They have plastids and are about 10–50 μm in size, with a flattened shape and an anterior groove or pocket. These organisms usually have two slightly unequal flagella at the edge of the pocket.

Alveolate: Alveolates are protists classified within Eukarya and form a major clade and superphylum. They are part of the SAR supergroup, along with stramenopiles and Rhizaria. Alveolates have tubulocristate mitochondria.

Dinoflagellate: Dinoflagellates are single-celled eukaryotes found in both marine and freshwater habitats. They vary in population based on temperature, salinity, and depth. These organisms are primarily photosynthetic, but some also engage in mixotrophic behavior by combining photosynthesis with prey ingestion.

Paramecium: Paramecium is a unicellular ciliate commonly used as a model organism. It is widely found in freshwater and marine environments, particularly stagnant basins and ponds. Paramecium is easily cultivated, making it popular for studying biological processes in classrooms and labs. Its usefulness as a model organism has led to it being called the "white rat" of the phylum Ciliophora.

Excavata: Excavata is a diverse group of single-celled organisms within the Eukaryota domain. It was first proposed in 1999 and later named by Thomas Cavalier-Smith in 2002. Excavata includes various free-living and symbiotic protists, and some important human parasites like Giardia and Trichomonas. Initially categorized under the now obsolete Protista kingdom, Excavates are distinguished by their unique cell arrangement observed through electron microscopy. They are considered to be a foundational lineage of flagellated organisms.

Euglenozoa: Euglenozoa is a diverse group of flagellate Discoba that includes common free-living species and important human parasites. It is composed of four major groups: Kinetoplastea, Diplonemea, Euglenida, and Symbiontida. These unicellular organisms are typically around 15-40μm in size, but some euglenids can reach lengths of up to 500μm.

Red algae: Red algae, or Rhodophyta, are one of the oldest eukaryotic algae groups. They make up one of the largest algae phyla, with over 7,000 recognized species. The majority of these species are multicellular, marine algae found in the class Florideophyceae. Red algae are abundant in marine habitats and less common in freshwater environments. Only about 5% of red algae species occur in freshwater, and they are more prevalent in warmer areas. Unlike other algae, there are no terrestrial red algae species. This may be due to the loss of core genes and evolutionary plasticity in their last common ancestor.

Rhizaria: Rhizaria is a diverse group of mostly unicellular eukaryotes. They are non-photosynthetic, with a few exceptions. Many foraminifera and radiolaria have a symbiotic relationship with unicellular algae. They vary in form but are predominantly amoeboids with pseudopods. Some Rhizaria possess mineral exoskeletons made of opal, celestite, or calcite. Certain species can grow large in size and contribute to the ocean's primary production.

Medicine: Medicine is a science and practice that cares for patients by diagnosing, treating, preventing, and managing diseases and injuries. It encompasses various healthcare practices, including biomedical research and technology. These methods utilize pharmaceuticals, surgery, psychotherapy, medical devices, and radiation, among others, to restore and maintain health.

First aid: First aid is immediate assistance given to treat minor or serious illnesses or injuries until medical help arrives. It aims to preserve life, prevent worsening of the condition, and promote recovery. It is usually provided by someone with basic medical training. Mental health first aid covers mental health issues, while psychological first aid treats people at risk of developing PTSD. Conflict first aid aims to preserve and recover social or relationship well-being and is being tested in Canada.

Health care: Health care refers to the promotion of well-being through prevention, diagnosis, treatment, and cure of various physical and mental issues. It encompasses a wide range of professions such as medicine, dentistry, nursing, and more, and includes primary, secondary, and tertiary care, along with public health efforts.

Medical ethics: Medical ethics is the study of ethical principles applied to clinical medicine and scientific research. It provides a basis for professionals to navigate conflicts using values like autonomy, non-maleficence, beneficence, and justice. All four values are important and can guide treatment decisions, but conflicts may require prioritizing certain moral elements. Medical ethics is crucial when dealing with involuntary treatment and commitment decisions.

Emergency medical services: Emergency medical services (EMS), also called ambulance or paramedic services, offer immediate pre-hospital treatment, stabilize serious injuries and illnesses, and transport patients to definitive care. They may be referred to as first aid, FAST, emergency, or ambulance squads, as well as other initials like EMAS or EMARS.

Coma: A coma is a prolonged state of unconsciousness where a person cannot be awakened or respond to stimuli. They don't have a normal sleep-wake cycle, lack voluntary actions, and may experience problems with breathing and circulation. Coma patients need extensive medical care to maintain their health and prevent complications. They are completely unaware, unable to feel, speak, or move. Comas can be caused naturally or induced medically.

Vegetative state: A vegetative state or post-coma unresponsiveness is a disorder of consciousness caused by severe brain damage, where patients are partially aroused but lack true awareness. After four weeks, it becomes a persistent vegetative state. This condition is deemed permanent several months after a non-traumatic brain injury or one year after a traumatic injury. The term unresponsive wakefulness syndrome may be used instead, as "vegetative state" carries negative connotations.

Syndrome: A syndrome is a collection of medical signs and symptoms that are often associated with a specific disease or disorder. The term derives from the Greek word meaning "concurrence." When a cause is identified, a syndrome may be classified as a disease. Sometimes, the terms syndrome, disease, and disorder are used interchangeably, which can confuse the understanding of medical diagnoses, particularly for inherited syndromes. Some syndromes have known causes and are more than just a set of signs and symptoms. On the other hand, some syndromes are not specific to only one disease and can be caused by different factors.

Nursing: Nursing is a healthcare profession dedicated to helping individuals, families, and communities achieve and maintain optimal health. Nurses have a unique approach to patient care and receive specialized training. They work in various specialties and often collaborate with other healthcare providers. Nurse practitioners, who have advanced degrees, can prescribe medication and practice independently in some parts of the US. The field of nursing has evolved to include advanced credentials and roles, reflecting changing healthcare needs.

Pharmacist: A pharmacist is a healthcare professional who prepares, dispenses, and manages medications. They provide pharmaceutical advice and guidance and can serve as primary care providers in the community. Pharmacists may also offer health screenings and immunizations.

Physician: A physician, also known as a doctor, is a health professional who practices medicine. They study, diagnose, and treat diseases and injuries to promote and restore health. Physicians may specialize in certain diseases or methods of treatment, or provide general medical care to individuals, families, and communities. Their work requires a deep understanding of medical science and expertise in its practical application.

Hospital: A hospital is a healthcare institution that provides specialized treatment with medical staff, equipment, and auxiliary healthcare. General hospitals have emergency departments for urgent health problems while district hospitals are major healthcare facilities with intensive care beds. Specialized hospitals include trauma centers, rehabilitation hospitals, children's hospitals, geriatric hospitals, and those treating specific medical needs. They can help reduce healthcare costs. Hospitals are classified as general, specialty, or government based on income sources.

Emergency department: The emergency department (ED) is a medical treatment facility specializing in emergency medicine, providing acute care for patients who arrive without prior appointment. Also known as accident and emergency (A&E), emergency room (ER), emergency ward (EW), or casualty department, it is usually located in a hospital or primary care center.

Pharmacy: Pharmacy is the science and practice that encompasses the discovery, production, preparation, dispensing, monitoring, and review of medications. Its aim is to ensure the safe, effective, and affordable use of medicines by linking health sciences with pharmaceutical and natural sciences. The field is evolving towards a more clinically-oriented practice as pharmaceutical industries predominantly manufacture drugs. Pharmacy practice can be categorized as either community or institutional, with the provision of direct patient care in these settings considered as clinical pharmacy.

Psychiatric hospital: Psychiatric hospitals, also called mental health hospitals, provide specialized treatment for severe mental disorders such as schizophrenia, bipolar disorder, eating disorders, and major depression. They play a crucial role in managing and addressing the complexities of these conditions.

Anesthesia: Anesthesia is a controlled, temporary loss of sensation or awareness induced for medical purposes. It involves analgesia, paralysis, amnesia, and unconsciousness. Those under its effects are referred to as anesthetized.

Palliative care: Palliative care optimizes quality of life and eases suffering for individuals with serious, complex, and often terminal illnesses. It involves early identification and impeccable treatment of physical, psychosocial, and spiritual problems. Previously disease-specific, palliative care now takes a patient-centered approach, addressing the needs and preferences of individuals with any chronic and ultimately fatal illness. The primary goal is to relieve suffering and enhance the well-being of terminally ill patients.

Medical test: A medical test is a procedure conducted in a medical setting to detect, diagnose, monitor diseases, or determine treatment. It includes physical exams, imaging, genetic and chemical analysis.

Sterilization (medicine): Sterilization in medicine refers to intentional methods of birth control that make a person unable to reproduce. These methods, available for both males and females, can be surgical or non-surgical. Sterilization procedures are meant to be permanent as reversal is typically challenging or impossible.

Medical diagnosis: Medical diagnosis is the identification of the disease or condition causing a person's symptoms. It involves gathering information through medical history, physical examination, and diagnostic tests. Posthumous diagnosis is also recognized.

Physical examination: A physical examination is a questioning and examination process performed by a medical practitioner to identify signs and symptoms of a medical condition. It involves assessing the patient's medical history, symptoms, and conducting a physical examination. This information aids in diagnosing the condition and forming a treatment plan, recorded as part of the medical record.

Autopsy: An autopsy is a surgical examination of a corpse to determine the cause of death, evaluate any diseases or injuries, or for research/educational purposes. It can also be referred to as necropsy for non-human animals.

Biopsy: A biopsy is a medical test performed by a surgeon, radiologist, or cardiologist to extract and examine sample cells or tissues to determine the presence or extent of a disease. The samples are fixed, dehydrated, sectioned, stained, and examined under a microscope. There are different types of biopsies, including excisional, incisional, and needle aspiration, depending on the extent of tissue removal. Biopsies are commonly done to gain insight into potential cancerous or inflammatory conditions.

Blood test: A blood test is a lab analysis done on a sample of blood to understand various aspects of health including diseases, organ function, mineral levels, and drug effectiveness. It is usually done by extracting blood from a vein or through a fingerprick. Different tests for specific blood components like glucose or cholesterol are often grouped together in a blood panel. Blood tests are commonly used in healthcare, drug detection, and clinical assessment.

Eye examination: An eye examination is a thorough assessment of vision and the ability to see and distinguish objects. It involves various tests and exams related to the eyes and is typically conducted by optometrists, ophthalmologists, or orthoptists. Regular eye exams are highly recommended by healthcare professionals as many eye diseases have no symptoms.

Lumbar puncture: A lumbar puncture, also known as a spinal tap, is a medical procedure where a needle is inserted into the spinal canal to collect cerebrospinal fluid for testing. It helps diagnose diseases of the central nervous system and can be used therapeutically in some cases. However, it is not safe when there is increased intracranial pressure. The procedure is generally safe, but a common side effect is post-dural-puncture headache if a small atraumatic needle is not used.

Pap test: The Pap test is a cervical screening method that detects precancerous and cancerous processes in the cervix or anus. Abnormal findings are followed by more sensitive diagnostic procedures to prevent cervical cancer. It was invented by Georgios Papanikolaou in the 1920s and simplified by Anna Marion Hilliard in 1957.

Reflex: A reflex is an automatic and rapid response to a stimulus in biology. It is an involuntary and unplanned action that happens almost instantly.

Blood pressure: Blood pressure is the force exerted by circulating blood on blood vessel walls. It primarily comes from the heart pumping blood. Blood pressure is commonly measured in the brachial artery, expressed as systolic pressure over diastolic pressure. It is measured in mmHg or kPa. The difference between systolic and diastolic pressures is called pulse pressure, and the average pressure during a cardiac cycle is called mean arterial pressure.

Pulse: A pulse is the tactile arterial palpation of the heartbeat using trained fingertips. It can be felt in various places where an artery is near the surface, such as the neck, wrist, groin, behind the knee, near the ankle, and on the foot. Measuring the pulse is equivalent to measuring the heart rate. It can also be measured by listening to the heartbeat with a stethoscope. The radial pulse is commonly measured using three fingers, with each finger serving a specific purpose. The study of the pulse is known as sphygmology.

Blood transfusion: Blood transfusion is the intravenous transfer of blood components to replace lost blood due to medical conditions. It has evolved from using whole blood to utilizing specific components like red blood cells, white blood cells, plasma, platelets, and clotting factors.

Symptomatic treatment: Symptomatic treatment refers to medical therapy that only addresses the symptoms of a disease, rather than its underlying cause. It aims to provide comfort and well-being by reducing signs and symptoms, and may also help minimize the consequences of the disease. In some cases, it is the only available treatment option. This type of treatment is particularly relevant for conditions like cancer, arthritis, neuropathy, tendinopathy, and injury, where it cannot alter the natural progression of the disease.

Surgery: Surgery is a medical practice that involves using manual or instrumental techniques to investigate and treat diseases, injuries, or alter bodily functions. It can also enhance appearance and remove unwanted tissues or foreign bodies. It is typically performed on humans but can include non-human animals.

Amputation: Amputation is the removal of a limb due to trauma, illness, or surgery. It is done to control pain, treat diseases like cancer or gangrene, or as a preventive measure. Amputation can be congenital, resulting from fetal limb constriction. Unfortunately, in some countries, it is used as a punishment for crimes. It has also been used in warfare and acts of terrorism as a tactic or injury. Certain cultures and religions consider minor amputations as ritualistic. The oldest evidence of amputation dates back to at least 31,000 years ago in Indonesian Borneo.

Dental restoration: Dental restoration, also known as dental fillings, is a treatment to restore missing tooth structure caused by decay or injury. It can replace the damaged structure with dental implants. There are direct and indirect methods, classified by location and size. Root canal filling is a specific technique used to fill the space in the tooth caused by pulp removal.

Dentures: Dentures are removable prosthetic devices that replace missing teeth. They can be supported by the surrounding tissues in the mouth and can either rely on bonding to existing teeth or dental implants. Dentures can be categorized into two types, based on whether they fit on the lower or upper jaw.

Organ transplantation: Organ transplantation is a medical procedure where organs are moved from one person to another to replace damaged or missing organs. This can happen at the same location or by transporting organs from one place to another. Transplants within the same person are autografts, while transplants between different individuals of the same species are allografts. Allografts can come from living or deceased donors.

Plastic surgery: Plastic surgery is a surgical specialty that restores or alters the human body. It has two main categories: reconstructive surgery (for improving function) and cosmetic surgery (for enhancing appearance). Reconstructive surgery includes craniofacial surgery, hand surgery, microsurgery, and treating burns. Plastic surgery overlaps with other specialties and involves tissue relocation skills. It treats conditions requiring such skills.

Therapy: Therapy refers to the process of addressing a health problem after medical diagnosis. It is often abbreviated as tx, Tx, or Tx alongside treatment.

Chemotherapy: Chemotherapy is a cancer treatment involving anti-cancer drugs given in a standardized regimen. It can cure, prolong life, or reduce symptoms. It falls under medical oncology, a discipline dedicated to pharmacotherapy for cancer.

Physical therapy: Physical therapy, also called physiotherapy, is a healthcare profession that involves physical examination, diagnosis, management, and rehabilitation to promote and restore health. Physical therapists, known as physiotherapists in some countries, provide patient education, physical interventions, and disease prevention for optimal health outcomes.

Radiation therapy: Radiation therapy utilizes ionizing radiation to treat cancer and control malignant cell growth. It can be curative for localized cancers and used as adjuvant therapy after tumor removal. Radiation therapy works synergistically with chemotherapy and is performed by radiation oncologists using linear particle accelerators.

Human body: The human body is made up of cells, tissues, and organs that work together to maintain a stable internal environment (homeostasis). These systems ensure the body's overall well-being and functionality.

Blood type: Blood type is a classification of blood based on the presence or absence of antibodies and inherited substances on red blood cells (RBCs). These substances can be proteins, carbohydrates, glycoproteins, or glycolipids. They form blood group systems and can be present on other cell types too.

Human brain: The human brain is the central organ of the nervous system, located inside the skull. It controls the activities of the body, receives and processes information from the senses, and makes decisions for the rest of the body.

Face: The face is an animal's head front with eyes, nose, and mouth where emotions are expressed. It plays a significant role in human identity, and damage or deformities can negatively impact the psyche.

Human eye: The human eye is a sensory organ that reacts to light, enabling us to see, maintain balance, and regulate our sleep-wake cycle.

Human tooth: Human teeth are part of the digestive system and are used to mechanically break down food for swallowing and digestion. There are four types of teeth - incisors, canines, premolars, and molars, each with a specific function. Incisors cut the food, canines tear it, and molars and premolars crush it. The teeth are anchored in the upper and lower jaw and are covered by gums. They are composed of different tissues of varying density and hardness.

Root canal: A root canal is the natural space inside a tooth that contains the pulp chamber and canals. It includes intricate branches connecting the canals to each other and the root surface.

Gastrointestinal tract: The gastrointestinal (GI) tract is the digestive system pathway from the mouth to the anus. It includes essential organs like the esophagus, stomach, and intestines. This tract processes food for nutrient extraction and energy absorption. Subsequently, waste is eliminated as feces through the anus. "Gastrointestinal" refers to anything related to the stomach and intestines.

Human skeleton: The human skeleton is the internal framework of the body, consisting of around 206 bones in adulthood. It makes up about 14% of the body's weight and reaches maximum mass between ages 25 and 30. The skeleton is divided into the axial (vertebral column, rib cage, skull) and appendicular (shoulder and pelvic girdles, upper and lower limb bones) regions.

Human voice: The human voice is the sound produced by the vocal tract in a person, encompassing activities like talking, singing, laughing, crying, and more. It relies on the vocal folds as the primary source and encompasses a range of frequencies.

Arm: The arm refers to the upper limb in human anatomy. Specifically, it includes the upper arm between the shoulder and elbow joints. The forearm is the lower part of the arm, extending between the elbow and wrist joints. Lastly, the hand is the extremity beyond the wrist.

Hand: A hand is a flexible, multi-fingered structure found at the end of the forearm in primates like humans, monkeys, and chimps. Some other animals like koalas and raccoons are also referred to as having "hands," though raccoons lack opposable thumbs.

Finger: A finger is a digit found on the forelimbs of most animals, including humans. It is flexible and opposable, serving as a crucial organ for tactile sensation, fine movements, and grasping objects. Most animals have five fingers, but shorter ones are called toes, while longer ones are referred to as fingers.

Human leg: The human leg refers to the lower limb of the body, including the foot, thigh, and sometimes even the hip or buttock area. It consists of major bones such as the femur, tibia, and fibula. The thigh is located between the hip and knee, while the calf and shin are found between the knee and foot.

Foot: The foot is a weight-bearing structure in vertebrates that allows movement. It is typically a separate organ at the end of a limb, composed of segments or bones, often including claws or nails.

Alternative medicine: Alternative medicine encompasses practices that lack scientific evidence, plausibility, or testability but aim to achieve healing effects. Unlike modern medicine, which relies on scientific methods and clinical trials, alternative therapies rely on anecdotes, testimonials, religion, tradition, and pseudoscience. Frequently referred to as New Age medicine or unorthodox medicine, alternative medicine is often associated with quackery and lacks the rigorous scientific foundation of mainstream medicine.

Chiropractic: Chiropractic is an alternative medicine focused on diagnosing, treating, and preventing musculoskeletal issues, particularly those related to the spine. It originated from esoteric sources and relies on pseudoscientific concepts.

Herbal medicine: Herbal medicine is the study of using medicinal plants, which are the basis of traditional medicine. Some herbal medicines, like artemisinin from Artemisia annua, have been translated into modern remedies. However, there is limited scientific evidence for the safety and efficacy of many plants used in herbalism today. The scope of herbal medicine also includes fungal and bee products, minerals, shells, and certain animal parts.

Homeopathy: Homeopathy is a pseudoscientific alternative medicine system created in 1796 by Samuel Hahnemann. Homeopaths believe that a substance causing symptoms in healthy individuals can cure similar symptoms in sick people. The remedies are produced using repeated dilution, making the final product chemically identical to the diluent without any trace of the original substance. Practitioners assert that these preparations, when taken orally, can treat or cure diseases.

Angiology: Angiology is a medical specialty focused on studying the circulatory and lymphatic systems, which include arteries, veins, and lymphatic vessels.

Cardiology: Cardiology is the study and medical treatment of heart and cardiovascular system disorders. It encompasses the diagnosis and management of congenital heart defects, coronary artery disease, heart failure, valvular heart disease, and electrophysiology. Cardiologists are specialized physicians in this field, while pediatric cardiologists focus on heart conditions in children. Cardiothoracic surgeons perform cardiac surgeries.

Dentistry: Dentistry is a medical field that focuses on the study, diagnosis, prevention, and treatment of diseases and conditions of the teeth, gums, and mouth. It also includes the management of the oral mucosa and the temporomandibular joint. Dentists are the practitioners in this field.

Dermatology: Dermatology is a medical specialty that focuses on the diagnosis and treatment of skin, hair, and nail conditions, as well as certain cosmetic issues. Dermatologists are specialized doctors who manage various skin diseases.

Gastroenterology: Gastroenterology is a medical specialty that deals with the digestive system and its disorders. It includes the gastrointestinal tract, which consists of the esophagus, stomach, small and large intestines, as well as the pancreas, gallbladder, and liver. The digestive system facilitates the movement of material, breaks it down, absorbs nutrients, and eliminates waste. Gastroenterologists, also known as GI doctors, specialize in this field and manage various conditions like reflux disease, bleeding, irritable bowel syndrome, inflammatory bowel disease, ulcers, gallbladder issues, hepatitis, pancreatitis, colitis, polyps, cancer, and nutritional problems.

Geriatrics: Geriatrics is a medical specialty focusing on the unique health needs of the elderly. It aims to promote health, prevent, diagnose, and treat diseases in older adults. Geriatric care is provided by specialized physicians called geriatricians, guided by individual patient needs. It benefits those with multiple chronic conditions or age-related complications, and can be sought when caregiving becomes too stressful or complex for family and caregivers to manage independently.

Hematology: Hematology is a medical field that studies the cause, treatment, and prevention of blood-related diseases. It deals with disorders affecting blood production, components, and clotting mechanism. These include hemophilia, anemia, bleeding disorders, blood cancers like leukemia, and lab analysis of blood.

Immunology: Immunology is the study of immune systems in all organisms. It is a branch of biology and medicine.

Neurology: Neurology is the medical field specializing in diagnosing and treating nervous system conditions. It deals with diseases affecting the brain, spinal cord, and peripheral nerves. Neurology heavily relies on neuroscience, the scientific study of the nervous system.

Oncology: Oncology is the study and treatment of cancer, including diagnosis, therapy, and prevention. It involves the care of patients after treatment and palliative care for terminal cases. The term originates from the Greek word ὄγκος meaning "tumor" or "mass". Oncology also encompasses ethical considerations and screening efforts for populations or relatives of patients.

Ophthalmology: Ophthalmology is a medical specialty focused on diagnosing and treating eye disorders. It includes surgical procedures and was previously known as oculism.

Otorhinolaryngology: Otorhinolaryngology is a medical specialty that deals with conditions of the head and neck. Experts in this field, known as otorhinolaryngologists or ENT surgeons, treat diseases affecting the ear, nose, throat, base of the skull, head, and neck. They manage both surgical and medical interventions, addressing functional issues related to eating, speaking, breathing, swallowing, and hearing. ENT surgery also involves the treatment of cancers, benign tumors, and reconstructive procedures of the head, neck, and face.

Pediatrics: Pediatrics is the branch of medicine that focuses on the medical care of infants, children, adolescents, and young adults. Age limits for pediatric care vary worldwide, with the United Kingdom providing care until the age of 18 and the United States suggesting care up to 21. Pediatricians, specialists in this field, work in various settings such as clinics, research centers, and hospitals, providing healthcare to children.

Pharmacology: Pharmacology is the scientific field that studies drugs and medications, analyzing their origin, composition, effects on the body, and potential for therapeutic use or toxicity. It focuses on understanding the interactions between living organisms and chemicals that impact normal or abnormal biochemical function. If a substance possesses medicinal properties, it falls under the category of pharmaceuticals.

Pharmacokinetics: Pharmacokinetics (PK) is a branch of pharmacology that studies how the body processes substances like drugs and chemicals. It examines their metabolism and tracks their journey from administration to elimination. PK uses mathematical modeling to analyze the relationship between a drug's concentration in the body and the time since it was given. Understanding PK is crucial for determining dosing, benefits, and adverse effects of drugs, in combination with pharmacodynamics (PD), which studies how drugs affect organisms. PK/PD models take both factors into account.

Prescription drug: Prescription drugs require a medical prescription and cannot be obtained without one, unlike over-the-counter drugs. This control is in place due to the risk of misuse, including drug abuse and unlicensed medical practices. Different jurisdictions have varying definitions of prescription drugs.

Psychiatry: Psychiatry is a medical specialty that diagnoses, prevents, and treats harmful mental conditions pertaining to mood, behavior, cognition, and perceptions.

Public health: Public health is the science of preventing disease, extending life, and promoting well-being through organized efforts of society. It involves analyzing health determinants and threats faced by populations of any size, from small groups to entire cities or continents. Health is considered in terms of physical, psychological, and social aspects.

Epidemiology: Epidemiology is the study of health and disease patterns in a specific population, including analyzing their distribution and determining factors.

Preventive healthcare: Preventive healthcare, also known as prophylaxis, involves implementing healthcare measures to proactively prevent diseases. It considers factors like genetics, environment, disease agents, and lifestyle choices that contribute to disease and disability. This approach recognizes that diseases start developing even before individuals become aware of them. Disease prevention strategies encompass various actions, categorized into primal, primary, secondary, and tertiary prevention.

Pulmonology: Pulmonology is a medical specialty focused on respiratory tract diseases. Also known as respirology or respiratory medicine, it is concerned with conditions affecting the chest.

Radiology: Radiology is a medical specialty that uses different imaging techniques to diagnose and treat diseases in humans and animals. It encompasses various modalities, including electromagnetic radiation-based methods like CT scans and fluoroscopy, as well as non-radiation methods. It also includes interventional radiology, in which minimally invasive procedures are performed with the assistance of imaging technologies.

Obstetrics and gynaecology: Obstetrics and gynaecology, a medical specialty, combines obstetrics and gynaecology. It plays a crucial role in women's healthcare.

Sexual and reproductive health: Sexual and reproductive health (SRH) refers to the study, medical services, and advocacy related to an individual's overall reproductive system and sexual well-being throughout their life.

Toxicology: Toxicology is a scientific discipline that studies the harmful effects of chemical substances on living organisms. It overlaps with biology, chemistry, pharmacology, and medicine. Toxicologists diagnose and treat exposures to toxins and toxicants. Dose and its effects on the organism are crucial in toxicology. Factors like dosage, duration of exposure, route, species, age, sex, and environment influence chemical toxicity. Toxicology contributes to evidence-based practices and is significant in cancer research, with certain toxins being explored as drugs for killing tumor cells, like ribosome-inactivating proteins tested for leukemia treatment.

Traditional medicine: Traditional medicine refers to the medical practices and knowledge that have been passed down through generations in different cultures. It includes the use of theories, beliefs, and experiences to maintain health and treat physical and mental illnesses. This form of medicine predates modern scientific medicine and is often contrasted with it.

Ayurveda: Ayurveda, an alternative medicine system originating in the Indian subcontinent, is widely practiced in India and Nepal with approximately 80% of the population using it. However, it is considered pseudoscientific in its theory and practice.

Acupuncture: Acupuncture is an alternative form of medicine originating from traditional Chinese medicine. It involves inserting thin needles into the body. However, acupuncture is considered pseudoscience, lacking scientific basis, and has been criticized as quackery.

Urology: Urology, or genitourinary surgery, is a medical specialty that deals with surgical and medical conditions affecting the urinary-tract system and reproductive organs. It encompasses the kidneys, adrenal glands, ureters, urinary bladder, urethra, and male reproductive organs.

Vaccination: Vaccination is the practice of giving vaccines to develop immunity from diseases. Vaccines can contain weakened or killed microorganisms, proteins, or toxins, which stimulate the immune system to prevent illness. It plays a vital role in achieving herd immunity, protecting vulnerable individuals who cannot be immunized. Vaccination is highly effective in preventing infectious diseases and has led to the eradication of smallpox and the elimination of diseases like polio and tetanus worldwide. However, low vaccination rates have caused outbreaks of diseases like measles in recent years, emphasizing the importance of widespread immunization. According to the WHO, vaccination saves millions of lives annually.

Veterinary medicine: Veterinary medicine is the field of medicine that focuses on preventing, diagnosing, treating, and managing diseases, disorders, and injuries in animals. It covers both domesticated and wild species, with a wide range of conditions.

Drug: A drug is a chemical substance that alters an organism's physiology, including psychology. It differs from food and other substances that provide nutrition. Drugs can be consumed through various methods such as inhalation, injection, smoking, ingestion, absorption, suppository, or dissolution under the tongue.

Medication: Medication is a drug that diagnoses, cures, treats, or prevents disease. It plays a pivotal role in medicine, specifically in drug therapy, where pharmacology and pharmacy drive advancements and ensure proper management.

Placebo: A placebo is a fake medical treatment, often in the form of inert tablets, injections, or procedures like sham surgery.

Amphetamine: Amphetamine is a CNS stimulant used to treat conditions like ADHD, narcolepsy, and obesity. It was discovered in 1887 and as a drug in the late 1920s. Amphetamine exists in two forms: levoamphetamine and dextroamphetamine. It has historically been used to treat nasal congestion and depression. Aside from its medical use, it is also used as an athletic and cognitive enhancer, and recreationally as an aphrodisiac and euphoriant. Due to health risks, unauthorized possession and distribution of amphetamine are tightly controlled.

Benzodiazepine: Benzodiazepines, known as "benzos," are depressant drugs that effectively treat anxiety disorders, insomnia, and seizures. They consist of fused benzene and diazepine rings. Chlordiazepoxide was the first benzodiazepine discovered in 1955, followed by diazepam in 1963. By 1977, they were the most prescribed medications worldwide. While their prescription rates decreased due to the introduction of SSRIs, benzodiazepines are still widely used globally.

Antibiotic: Antibiotics are antimicrobial substances used to fight bacterial infections. They either kill or inhibit the growth of bacteria, making them important in treatment and prevention. However, they are ineffective against viruses and fungi, which require specific antiviral and antifungal drugs.

Penicillin: Penicillin is a group of antibiotics derived from Penicillium moulds. The two main compounds in clinical use are penicillin G and penicillin V. These antibiotics were one of the first effective treatments for bacterial infections caused by staphylococci and streptococci. Despite some bacteria developing resistance, penicillins are still widely used today for various bacterial infections.

Quinine: Quinine is a medication primarily used to treat malaria and babesiosis. It is effective against chloroquine-resistant Plasmodium falciparum malaria when artesunate is unavailable. However, it is not recommended for nocturnal leg cramps due to potential serious side effects. It can be taken orally or intravenously, and some areas have reported malaria resistance to quinine. Additionally, quinine is used in tonic water to provide a bitter taste.

Analgesic: An analgesic is a drug used to relieve pain. It is different from anesthetics, which temporarily reduce sensation. Some drugs have both analgesic and anesthetic effects.

Aspirin: Aspirin (acetylsalicylic acid) is an NSAID that alleviates pain, reduces fever, inflammation, and acts as an antithrombotic. It is prescribed for conditions like Kawasaki disease, pericarditis, and rheumatic fever.

Vaccine: A vaccine is a biological preparation that provides immunity to specific infectious or malignant diseases. It contains a harmless version of the disease-causing agent, which triggers the immune system to recognize and destroy the real agent and any related microorganisms encountered in the future. Vaccines' safety and effectiveness have been extensively researched and confirmed.

Vaccine hesitancy: Vaccine hesitancy refers to the delay or refusal of vaccines despite their availability and supporting evidence. It includes refusing, delaying, having uncertainty, or selectively using vaccines. The scientific consensus strongly affirms the safety and effectiveness of vaccines. Vaccine hesitancy leads to disease outbreaks and preventable deaths, making it a significant global health threat according to the World Health Organization.

Polio vaccine: Polio vaccines, administered through injection (IPV) or orally (OPV), are important in preventing poliomyelitis (polio). The World Health Organization highly recommends full vaccination for all children. These vaccines have successfully eradicated polio from most regions worldwide, significantly reducing the number of reported cases from 350,000 in 1988 to just 33 in 2018.

Smallpox vaccine: The smallpox vaccine is the first vaccine developed against a contagious disease. Edward Jenner proved in 1796 that cowpox infection protected against deadly smallpox. Cowpox acted as a natural vaccine until the modern smallpox vaccine emerged. Thanks to a global WHO vaccination campaign from 1958 to 1977, smallpox was eradicated, the only disease to achieve this. Although not used routinely, the vaccine continues to be produced to guard against bioterrorism and biological warfare.

Alcohol (drug): Alcohol, also known as ethanol, is a depressant drug found in alcoholic beverages. Consumed for recreational purposes, it induces effects like happiness, decreased anxiety, and increased sociability. However, it also impairs cognitive, memory, motor, and sensory functions, as well as depresses the central nervous system. Alcohol is a prominent and ancient recreational drug.

Alcohol intoxication: Alcohol intoxication, commonly known as drunkenness, is the result of consuming alcohol. It is characterized by behavioral and physical effects caused by the toxic properties of ethanol, the main psychoactive component in alcoholic beverages. Acetaldehyde, a byproduct of alcohol metabolism, can also contribute to physiological symptoms. Hangovers may occur several hours later.

Cannabis (drug): Cannabis, also known as marijuana or weed, is a psychoactive drug derived from the cannabis plant. It has been used for recreational and medicinal purposes for centuries. The main psychoactive compound in cannabis is THC, but there are over 480 other compounds including CBD. It can be consumed through smoking, vaporizing, ingesting, or as an extract.

Opium: Opium is a dried latex from the seed capsules of the opium poppy. It contains morphine, which is chemically processed into heroin and other opioids for medical and illegal use. Opium latex also contains codeine, thebaine, papaverine, and noscapine. It is obtained through a labor-intensive method of scratching immature seed pods by hand. The term "meconium" historically referred to weaker opium preparations from other parts of the poppy.

Tobacco: Tobacco, a plant in the Nicotiana genus of the Solanaceae family, refers to products made from cured leaves. With over 70 known species, N. tabacum is the main commercial crop, while N. rustica is a stronger variant used in some countries.

Disease: A disease is an abnormal condition that negatively impacts an organism's structure or function. It is not caused by external injury but can be due to factors like pathogens or internal dysfunctions. Diseases are medical conditions with specific signs and symptoms. Internal dysfunctions of the immune system can lead to different diseases, including immunodeficiency, allergies, and autoimmune disorders.

Acne: Acne is a chronic skin condition caused by clogged hair follicles due to oil and dead skin cells. It leads to blackheads, whiteheads, pimples, oily skin, and sometimes scarring. Commonly affecting the face, chest, and back, it can cause low self-esteem, anxiety, and even depression or suicidal thoughts in severe cases.

Allergy: Allergies are hypersensitivity conditions caused by the immune system reacting to harmless substances. They include hay fever, food allergies, skin conditions, asthma, and severe reactions. Symptoms can include red eyes, rash, sneezing, coughing, runny nose, difficulty breathing, or swelling. Food intolerances and food poisoning are separate conditions.

Alzheimer's disease: Alzheimer's disease (AD) is a progressive neurodegenerative disease, responsible for the majority of dementia cases. It begins with difficulty in remembering recent events and later leads to language issues, disorientation, mood swings, and behavioral problems. Patients often withdraw from society and their bodily functions gradually deteriorate until death. Life expectancy after diagnosis ranges from three to nine years.

Anemia: Anemia is a blood disorder characterized by a reduced ability of the blood to carry oxygen due to a low number of red blood cells, decreased hemoglobin, or abnormalities in hemoglobin. Symptoms can include tiredness, weakness, shortness of breath, headaches, and reduced exercise capacity. Acute anemia may lead to confusion, fainting, loss of consciousness, and increased thirst. It can be temporary or long term, ranging from mild to severe. Preoperative anemia increases the risk of requiring a blood transfusion during surgery. The term is derived from the Greek meaning 'lack of blood'.

Arthritis: Arthritis is a joint disorder causing pain, stiffness, swelling, and limited motion. It can affect other organs and may have a gradual or sudden onset.

Asthma: Asthma is a chronic lung disease characterized by inflammation and obstruction of the airways. Symptoms include wheezing, coughing, chest tightness, and shortness of breath, which can occur frequently or intermittently. It may worsen at night or during exercise.

Autoimmune disease: Autoimmune diseases are caused by the immune system mistakenly attacking healthy body parts instead of foreign organisms. There are over 80 known autoimmune diseases, with the possibility of more than 100 distinct conditions. Any part of the body can be affected.

Bronchitis: Bronchitis is inflammation of the bronchi causing coughing. It often starts as an infection in the nose, ears, throat, or sinuses and spreads to the bronchi. Symptoms include coughing up mucus, wheezing, difficulty breathing, and chest pain. Bronchitis can be either acute or chronic.

Cardiovascular disease: Cardiovascular disease (CVD) refers to a broad range of conditions affecting the heart and blood vessels. It includes diseases like coronary artery disease, heart failure, hypertension, rheumatic heart disease, and more. CVDs can encompass conditions related to the heart, blood vessels, and various heart abnormalities.

Myocardial infarction: A myocardial infarction, or heart attack, occurs when blood flow to the heart muscle is reduced or blocked, leading to damage. Common symptoms include chest pain, shortness of breath, and fatigue. Some people may experience atypical symptoms, such as neck or arm pain. Elderly individuals may have a heart attack without typical symptoms. Complications can include heart failure, irregular heartbeat, shock, or even cardiac arrest.

Chronic obstructive pulmonary disease: COPD is a progressive lung disease that causes long-term respiratory symptoms and airflow limitation. It is characterized by shortness of breath, a cough, and difficulty in performing everyday activities. Emphysema and chronic bronchitis are the most common types of COPD, but other phenotypes exist. Emphysema damages lung tissue, while chronic bronchitis is a productive cough lasting for at least three months per year for two years. Both conditions can exist without airflow limitation but increase the risk of developing COPD. COPD is incurable but preventable and treatable, often coexisting with asthma and systemic inflammation.

Cirrhosis: Cirrhosis is a liver condition where scar tissue replaces healthy tissue, impairing liver function. It develops slowly, causing fatigue, appetite loss, weight loss, and abdominal discomfort. As it worsens, symptoms include swelling, jaundice, easy bruising, and spider-like blood vessels. Complications can include infections, mental confusion, bleeding, and liver cancer.

Dementia: Dementia is a decline in cognitive abilities affecting everyday activities. Symptoms include memory problems, impaired thinking, behavior changes, emotional difficulties, language struggles, and decreased motivation. It progresses in stages and has a profound impact on individuals, caregivers, and social relationships. Diagnosis requires observing significant cognitive decline beyond normal aging.

Diabetes: Diabetes, or diabetes mellitus, is a group of endocrine diseases causing high blood sugar levels. It is caused by insufficient insulin production or cells not responding to insulin. Common symptoms include thirst, frequent urination, weight loss, and blurred vision. If untreated, it can lead to various health complications, including cardiovascular disorders, eye and kidney problems, and nerve damage. Untreated or poorly treated diabetes causes around 1.5 million deaths annually.

Epilepsy: Epilepsy is a non-communicable neurological disorder characterized by recurrent seizures caused by abnormal electrical activity in the brain. It is diagnosed when a person experiences two or more unprovoked seizures. These seizures can range from subtle to severe, sometimes leading to physical injuries. Epilepsy is a chronic condition with no immediate underlying cause, and isolated seizures provoked by specific triggers are not considered epilepsy. People with epilepsy may face varying degrees of social stigma and different treatment approaches worldwide.

Gout: Gout is a type of inflammatory arthritis that causes recurring attacks of red, tender, swollen joints. These attacks are caused by the buildup of needle-like crystals called uric acid crystals. The pain comes on quickly, usually intensifying within 12 hours. The joint at the base of the big toe is commonly affected, known as podagra. Gout can also lead to the formation of tophi, kidney stones, or kidney damage.

Hypertension: Hypertension, or high blood pressure, is a chronic condition characterized by persistently elevated blood pressure in the arteries. It often has no symptoms but increases the risk of serious health problems such as stroke, heart disease, kidney disease, and dementia. This global issue also contributes significantly to premature death.

Meningitis: Meningitis is the inflammation of membranes covering the brain and spinal cord. It causes fever, severe headaches, vomiting, neck stiffness, and sometimes sensitivity to light.

Migraine: Migraine is a complex neurological disorder causing severe headaches, typically on one side, accompanied by nausea, sensitivity to light and sound, and other symptoms. It is often triggered by physical activity and can include a premonitory period called aura. Migraine varies in its presentation, ranging from occasional attacks to chronic disease.

Multiple sclerosis: Multiple sclerosis (MS) is an autoimmune disease that damages the protective covering of nerve cells in the brain and spine, impairing the transmission of signals in the nervous system. This results in a variety of physical, mental, and sometimes psychiatric symptoms, such as vision problems, muscle weakness, and coordination difficulties. MS can present in different forms, with symptoms worsening over time if untreated.

Parkinson's disease: Parkinson's disease (PD) is a chronic disorder of the central nervous system that affects motor and non-motor functions. It causes symptoms like tremors, slowed movements, and difficulty walking. As the condition progresses, cognitive and behavioral issues may arise, alongside sleep and sensory problems. Parkinson's disease dementia is commonly seen in advanced stages.

Tooth decay: Tooth decay, or cavities, is caused by acidic bacteria that break down teeth. Symptoms include pain, difficulty eating, and discoloration of the cavities. Complications can lead to tissue inflammation, tooth loss, and infection.

Injury: Injury refers to physiological damage in living organisms, across humans, animals, and plants.

Major trauma: Major trauma refers to severe injuries that can result in lasting disability or death. It can be caused by falls, car accidents, stabbings, or gunshots. Prompt medical care and transportation to a suitable facility are crucial to prevent serious consequences. A thorough physical evaluation and imaging techniques are used for accurate injury assessment and treatment planning.

Wound: A wound is a damage or disruption to living tissue, such as skin or organs. It can be caused by trauma or disease. Appearance varies based on factors like location and depth. Wound treatment depends on classification, so evaluation by a professional is crucial. Wounds undergo a healing process with several stages. Factors like age, oxygenation, and medical conditions affect healing rate.

Aneurysm: An aneurysm is a localized bulge or weakening of a blood vessel wall, which can be hereditary or acquired. Aneurysms can lead to clot formation and rupture, causing uncontrolled bleeding. They can occur in any blood vessel, with examples including brain aneurysms, aortic aneurysms, and heart-related aneurysms. A rare type is congenital atrial septal aneurysm.

Bleeding: Bleeding, also known as hemorrhage or blood loss, is the escape of blood from damaged blood vessels. It can occur internally or externally through natural openings or punctures in the skin. Excessive blood loss, called exsanguination, can lead to death. Hemostasis, the stopping or controlling of bleeding, is crucial in first aid and surgery. Normally, a healthy person can tolerate losing up to 10-15% of their total blood volume without severe medical complications.

Blunt trauma: Blunt trauma refers to a physical injury caused by a strong impact without piercing the body's surface. It is different from penetrating trauma where the object creates an open wound. This type of trauma can happen due to direct force on a body part, often occurring in road accidents, assaults, sports injuries, and falls among older individuals.

Bone fracture: A bone fracture is a break in any bone, which can range from a partial to a complete break. Severe fractures can result in the bone breaking into multiple fragments called comminuted fractures. Fractures can be caused by high force impacts, stress, or medical conditions weakening the bones, such as osteoporosis or bone cancer. Pathologic fractures occur as a result of these medical conditions.

Brain damage: Brain damage, also known as neurotrauma or brain injury (BI), is the deterioration or destruction of brain cells. It can result from various internal and external factors, typically caused by significant and indiscriminate trauma.

Concussion: A concussion, also called mTBI, is a head injury causing temporary brain dysfunction. Symptoms include memory loss, headaches, difficulty concentrating, and nausea. Symptoms can appear immediately or days after injury, and may last up to 2 weeks in adults and 4 weeks in children. Loss of consciousness is rare in sports-related concussions among children.

Bruise: A bruise, also called a contusion, occurs when capillaries in the tissue are damaged by trauma, resulting in localized bleeding. This bleeding leads to a visible discoloration near the skin's surface. The bruise remains visible until the blood is absorbed or cleared by the immune system. Bruises may involve capillaries in the skin, subcutaneous tissue, muscle, or bone.

Burn: A burn is an injury to skin or other tissues caused by heat, cold, electricity, chemicals, friction, or UV radiation. Most burns occur at home or in the workplace, with common risks including hot liquids, fire, and chemical or electric burns. Alcoholism, smoking, self-harm, and violence are additional risk factors.

Cardiac arrest: Cardiac arrest, or sudden cardiac arrest, refers to the sudden and unexpected cessation of the heart's beating. This leads to inadequate blood circulation, resulting in reduced blood flow to the brain and other organs. Insufficient blood supply to the brain can cause loss of consciousness and unresponsiveness. Cardiac arrest is characterized by the absence of central pulses and abnormal breathing.

Frostbite: Frostbite is a freezing skin injury caused by exposure to extremely low temperatures. It commonly affects fingers, toes, nose, ears, cheeks, and chin. Initial symptoms include cold and tingling sensation, followed by skin discoloration and swelling. Complications can include hypothermia or compartment syndrome.

Hypothermia: Hypothermia is when a person's body temperature drops below 35.0 °C (95.0 °F). Symptoms range from shivering and confusion in mild cases to hallucinations, increased risk of heart stopping, and paradoxical undressing (removal of clothing) in severe cases.

Hypoxia (medicine): Hypoxia is a condition where the body or a specific region lacks sufficient oxygen supply at the tissue level. It can be generalized, affecting the whole body, or local, affecting a specific area. While hypoxia is usually a pathological condition, changes in oxygen levels can occur during intense physical activity.

Respiratory failure: Respiratory failure occurs when the respiratory system cannot maintain normal levels of oxygen and carbon dioxide in the blood. It is classified as Type 1 or Type 2 based on carbon dioxide levels and can be acute or chronic. Symptoms include abnormal blood gases, increased respiratory rate, and increased work of breathing. It can lead to altered mental status due to brain ischemia.

Shock (circulatory): Shock is a condition where insufficient blood flow occurs due to circulatory system issues. Early signs include weakness, rapid heart rate, breathing, sweating, anxiety, and increased thirst. If left untreated, it can escalate to confusion, unconsciousness, or cardiac arrest.

Stroke: A stroke is a serious medical condition where lack of blood flow to the brain causes cell death, leading to impaired brain function. It can be classified into two main types: ischemic (caused by insufficient blood flow) and hemorrhagic (caused by bleeding). Both types result in specific areas of the brain failing to work properly.

Poison: A poison is a harmful or lethal chemical substance that can be defined and used in various scientific fields and industries. It can also be applied colloquially or figuratively with a broad meaning.

Mushroom poisoning: Mushroom poisoning refers to ingestion of toxic mushrooms, causing symptoms ranging from mild gastrointestinal discomfort to death within 10 days. It occurs due to ingestion of mushrooms containing secondary metabolites produced by the fungus.

Toxicity: Toxicity measures the ability of a chemical or substance mixture to harm an organism, whether by affecting its entirety or specific parts like cells or organs. The term is often used interchangeably with "poisoning" in everyday language.

Cerebral palsy: Cerebral palsy (CP) is a childhood condition causing movement disorders. It includes poor coordination, stiff and weak muscles, tremors, and can affect sensation, vision, hearing, and speech.

Color blindness: Color blindness, or color vision deficiency (CVD), is a condition where individuals have a decreased ability to see or differentiate colors. It can range from subtle impairments to the complete inability to perceive colors. This problem is typically inherited and caused by variations in the functionality of cone cells in the retina, which are responsible for color vision. The most common type of color blindness is red-green color blindness, affecting 8% of males and 0.5% of females. Other rarer genetic conditions and external factors can also cause color blindness. Additionally, color vision tends to worsen with age.

Down syndrome: Down syndrome, also known as trisomy 21, is a genetic disorder resulting from the presence of an extra copy of chromosome 21. It is characterized by developmental delays, intellectual disability, and distinct physical traits. There are three types: Trisomy 21, Mosaic Down syndrome, and Translocation Down syndrome, all sharing the same features.

Hearing loss: Hearing loss is the inability to hear, either partially or completely. It can be present from birth or acquired later in life, affecting one or both ears. In children, it can hinder language acquisition, while in adults, it can impair social interactions and work-related tasks. It can be temporary or permanent, and age-related hearing loss typically involves both ears due to cochlear hair cell loss. For some, especially older individuals, hearing loss can lead to feelings of isolation and loneliness.

Intellectual disability: Intellectual disability, also known as general learning disability, is a neurodevelopmental disorder characterized by significantly impaired intellectual and adaptive functioning. It is defined by an IQ under 70 and deficits in two or more adaptive behaviors. Adaptive behaviors encompass conceptual, social, and practical skills used in everyday tasks.

Dyslexia: Dyslexia is a learning disability that affects reading and writing. It manifests differently in individuals, leading to spelling, reading, and writing difficulties. This involuntary condition is often noticed during school years but doesn't affect the desire to learn. Those with dyslexia commonly have higher rates of ADHD, developmental language disorders, and difficulties with numbers.

Physical disability: A physical disability refers to a restriction on a person's physical abilities, including mobility, dexterity, stamina, and daily living functions. It encompasses various impairments like respiratory disorders, blindness, epilepsy, and sleep disorders.

Visual impairment: Visual impairment refers to the partial or total inability to perceive visual information. It is commonly referred to as low vision or blindness. Without treatment or aids such as glasses, visual impairment can make daily tasks like reading and walking challenging. It may also indicate underlying medical issues, even though some cases can be temporary.

Brain tumor: A brain tumor is an abnormal mass of cells that can be cancerous or non-cancerous. There are two main types: primary tumors that start in the brain and secondary tumors that spread from other parts of the body. Symptoms vary depending on the tumor's size and location, including headaches, seizures, vision problems, vomiting, and mental changes. Other symptoms may include difficulty walking, speaking, sensations, or unconsciousness.

Cancer: Cancer is a disease characterized by abnormal cell growth that can invade and spread in the body. Unlike benign tumors, cancer spreads. Signs may include lumps, abnormal bleeding, prolonged cough, weight loss, and changes in bowel movements. These symptoms can indicate cancer or other causes. Humans can be affected by over 100 types of cancer.

Carcinogen: A carcinogen is any substance, radiation, or radionuclide that can cause cancer by damaging the genome or disrupting cellular processes. Examples include asbestos, dioxins, and tobacco smoke. Carcinogenicity can arise from natural or synthetic substances, and it is not always immediately toxic, making its effects potentially hidden or gradual.

Breast cancer: Breast cancer is a malignant tumor originating from breast cells. Symptoms include breast lump, change in shape, skin dimpling, milk rejection, nipple inversion, nipple discharge, or red/scaly skin patches. Advanced cases may have bone pain, swollen lymph nodes, shortness of breath, or yellow skin.

Colorectal cancer: Colorectal cancer, also called bowel, colon, or rectal cancer, occurs when cancer develops in the colon or rectum. Symptoms may include blood in the stool, changes in bowel movements, weight loss, and fatigue. It is mainly caused by aging and lifestyle factors, but some genetic disorders can also contribute. Risk factors include diet, obesity, smoking, lack of physical activity, and inflammatory bowel disease. Certain dietary factors like red meat, processed meat, and alcohol increase the risk. Less than 5% of cases are caused by inheritable genetic disorders. The cancer typically starts as a benign tumor, often in the form of a polyp, which eventually becomes cancerous.

Leukemia: Leukemia is a type of blood cancer that starts in the bone marrow, causing an excess of abnormal blood cells known as blasts or leukemia cells. Symptoms include bleeding, bone pain, fatigue, fever, and a higher susceptibility to infections. Diagnosis involves blood tests or bone marrow biopsy.

Lung cancer: Lung cancer, or lung carcinoma, is a malignant tumor that originates in the lung. It is usually caused by genetic damage to cells in the airways, often from smoking or inhaling harmful chemicals. Damaged cells multiply uncontrollably, forming tumors that can spread, affecting lung function. Eventually, the tumors can metastasize, spreading to other areas of the body.

Lymphoma: Lymphoma is a type of cancer that originates from lymphocytes, affecting the blood and lymph system. It is characterized by enlarged, painless lymph nodes, fever, night sweats, unexplained weight loss, itching, and constant tiredness.

Neoplasm: A neoplasm is an abnormal tissue growth called neoplasia, that occurs independently from the surrounding tissue, even if the initial trigger is removed. It often forms a mass known as a tumor.

Prostate cancer: Prostate cancer is the uncontrolled growth of cells in the prostate gland. It is often detected through blood tests that measure prostate-specific antigen (PSA) levels. A biopsy is necessary to confirm the diagnosis and determine the Gleason score, which indicates the aggressiveness of the tumor. Medical imaging is used to check for cancer spread. The stage of the cancer is determined based on the Gleason score, PSA levels, and imaging results. A higher stage suggests a more advanced and dangerous disease.

Skin cancer: Skin cancer is a common form of cancer in humans arising from abnormal cells in the skin. It can invade other parts of the body. There are three main types: basal-cell (BCC), squamous-cell (SCC), and melanoma. BCC grows slowly and rarely spreads, appearing as a shiny raised area with blood vessels or an ulcer. SCC is more likely to spread and presents as a hard lump or an ulcer. Melanomas are the most aggressive, exhibiting changes in size, shape, color, itchiness, and bleeding.

Melanoma: Melanoma is a cancer originating from melanocytes, the cells that produce pigment. It primarily affects the skin, although it can also occur in the mouth, intestines, or eye. Melanomas often develop from moles, and symptoms include changes in size, shape, color, itchiness, or skin breakdown.

Infection: An infection is when harmful pathogens invade and multiply in tissues, leading to a reaction by the host's tissues to the infectious agent and its toxins. It can cause an infectious disease, which is a communicable illness resulting from an infection.

Pathogen: A pathogen is an organism or agent that can cause disease. It may also be called an infectious agent or germ.

Fungal infection: A fungal infection, also called mycosis, is a disease caused by fungi that affects different parts of the body. It is divided into three types: superficial, subcutaneous, and systemic. Superficial infections include common skin conditions like tinea and yeast infections. Subcutaneous infections affect tissues beneath the skin. Systemic infections are more serious and can affect organs like the lungs and brain. Symptoms vary and can range from rashes to pneumonia-like symptoms.

Virus: A virus is a tiny infectious agent that can only reproduce within living cells. They infect all forms of life, including animals, plants, and microorganisms. Viruses are abundant in all ecosystems and are the most prevalent biological entity. Over 11,000 virus species have been extensively studied since their initial discovery in the late 19th century. The study of viruses is known as virology, a specialized field within microbiology.

Prion: A prion is a misfolded protein that can cause other proteins to also misfold, leading to fatal diseases known as transmissible spongiform encephalopathies (TSEs) in humans and animals. Prions can misfold spontaneously, due to genetic mutations, or when exposed to misfolded proteins. The abnormal structure of prions allows them to trigger cellular death and induce a cascade of protein misfolding.

Foodborne illness: Foodborne illness refers to sickness caused by harmful bacteria, viruses, parasites, toxins (like aflatoxins), and prions present in contaminated food. It can result from consuming undercooked or unsafe food, causing various health issues.

Sexually transmitted infection: A Sexually Transmitted Infection (STI), also known as a Sexually Transmitted Disease (STD) or venereal disease (VD), is an infection spread through sexual activity. Common forms of transmission include vaginal, anal, oral, or manual sex. STIs often don't show symptoms initially, making it easy to spread the infection unknowingly. Symptoms can include vaginal or penile discharge, genital ulcers, and pelvic pain. Infertility can occur with certain STIs.

Encephalitis: Encephalitis is brain inflammation that can cause variable symptoms such as altered consciousness, headache, fever, confusion, stiff neck, and vomiting. Complications may include seizures, hallucinations, speech difficulties, memory problems, and hearing issues.

Gangrene: Gangrene is tissue death caused by reduced blood flow. Symptoms include skin discoloration, numbness, swelling, pain, skin breakdown, and coolness. It commonly affects the feet and hands. Infectious gangrene may be accompanied by a fever or sepsis.

Gastroenteritis: Gastroenteritis, also known as infectious diarrhea or gastro, is inflammation of the stomach and intestines. It causes symptoms such as diarrhea, vomiting, abdominal pain, and can also lead to fever, fatigue, and dehydration. The condition typically lasts less than two weeks and is sometimes referred to as "stomach flu" in the U.S.

Dysentery: Dysentery, also called the bloody flux, causes bloody diarrhea and can lead to symptoms like fever, abdominal pain, and a sense of incomplete defecation. It can also result in dehydration.

Pneumonia: Pneumonia is an inflammatory lung condition impacting small air sacs called alveoli. It causes symptoms like cough, chest pain, fever, and breathing difficulties. The severity of pneumonia varies.

Anthrax: Anthrax is a bacterial infection caused by Bacillus anthracis. It can be contracted through contact with skin, inhalation, or ingestion. Symptoms can appear within one day to more than two months. The skin form presents as a blister that turns into a painless ulcer with a black center. Inhalation form causes fever, chest pain, and difficulty breathing. The intestinal form leads to diarrhea, abdominal pain, nausea, and vomiting.

Botulism: Botulism is a rare and deadly illness caused by a toxin produced by the bacterium Clostridium botulinum. It starts with weakness, blurred vision, fatigue, and speech difficulties. Weakness later spreads to the limbs, chest, and abdomen. Vomiting, abdominal swelling, and diarrhea may also occur. Consciousness is usually not affected and fever is uncommon.

Chlamydia: Chlamydia, caused by Chlamydia trachomatis, is a sexually transmitted infection that often goes unnoticed. Symptoms may occur weeks after infection and include discharge, burning sensation, and swelling. It can lead to pelvic inflammatory disease in women, which can cause infertility or ectopic pregnancy.

Cholera: Cholera is a bacterial infection that affects the small intestine. Common symptoms include watery diarrhea, vomiting, and muscle cramps. In severe cases, it can quickly lead to dehydration and electrolyte imbalance, causing sunken eyes, cold skin, and decreased skin elasticity. Symptoms usually appear within two hours to five days after exposure.

Diphtheria: Diphtheria, caused by Corynebacterium diphtheriae, is an infection with varying symptoms. It starts with a sore throat and fever, gradually progressing to the formation of a grey or white patch in the throat. Severe cases can block the airway and cause a barking cough. Swelling of the neck and involvement of other body parts are possible. Serious complications like myocarditis, nerve inflammation, kidney problems, and bleeding issues may arise.

Gonorrhea: Gonorrhea, also known as the clap, is a sexually transmitted infection caused by the bacterium Neisseria gonorrhoeae. It can infect the genitals, mouth, or rectum. Symptoms in men include pain or burning during urination, penile discharge, and testicular pain. Women may experience burning during urination, vaginal discharge, bleeding between periods, or pelvic pain. If left untreated, it can lead to serious complications such as pelvic inflammatory disease in women and inflammation of the epididymis in men. Some infected individuals may remain asymptomatic. If gonorrhea is not treated, it can spread to the joints or heart valves.

Leprosy: Leprosy, also known as Hansen's disease, is a chronic infection caused by bacteria. It can damage the nerves, respiratory tract, skin, and eyes. The infection may lead to a loss of sensation, resulting in the amputation of extremities. Symptoms can appear within a year or take decades to manifest. Muscle weakness and impaired vision are also common symptoms.

Lyme disease: Lyme disease, also known as Lyme borreliosis, is a bacterial infection transmitted by ticks. The main symptom is a red rash called erythema migrans, which appears a week after being bitten. Other early signs can include fever, headaches, and tiredness. If left untreated, it can lead to facial paralysis, joint pain, and severe headaches. In some cases, recurrent joint pain and tingling sensations may occur. Even with treatment, about 10 to 20% of individuals may experience long-term joint pain, memory issues, and fatigue.

Bubonic plague: The bubonic plague is a type of plague caused by the bacterium Yersinia pestis. Symptoms include flu-like symptoms, swollen and painful lymph nodes, and acral necrosis. Occasionally, swollen lymph nodes may burst.

Scarlet fever: Scarlet fever, also known as scarlatina, is an infectious disease caused by Streptococcus pyogenes. It primarily affects children aged 5-15. Symptoms include sore throat, fever, headache, swollen lymph nodes, and a distinctive red rash that feels rough like sandpaper. The face is flushed, the tongue may be red and bumpy, and the rash is hard to see on darker skin. The infection is caused by toxins released by the bacteria.

Syphilis: Syphilis, caused by Treponema pallidum subspecies pallidum, is a sexually transmitted infection that manifests in four stages. The initial stage presents with a single or multiple sores (chancre), followed by a rash in secondary syphilis. Latent syphilis is asymptomatic, while tertiary syphilis may cause gummas, neurological issues, or heart problems. Often referred to as "the great imitator," syphilis shares symptoms with various diseases.

Tetanus: Tetanus, also known as lockjaw, is a bacterial infection caused by Clostridium tetani. It is characterized by muscle spasms starting in the jaw and spreading throughout the body, lasting a few minutes each. Spasms can be severe, leading to bone fractures. Other symptoms include fever, sweating, headache, trouble swallowing, high blood pressure, and a fast heart rate. Onset typically occurs 3 to 21 days after infection. Recovery may take months, but 10% of cases are fatal.

Tuberculosis: Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis bacteria. It primarily affects the lungs but can also target other parts of the body. Many infections have no symptoms, called latent TB, but about 10% progress to active disease. Symptoms of active TB include chronic cough with bloody phlegm, fever, night sweats, and weight loss. Infection in other organs may cause various symptoms. Left untreated, TB can be fatal for about half of those affected.

Typhoid fever: Typhoid fever, caused by Salmonella enterica serotype Typhi bacteria, shows symptoms such as high fever, abdominal pain, and constipation. Gradual onset, rose-colored rash, and confusion can also occur. Without treatment, symptoms can last for weeks or months. Diarrhea is rare, but individuals can carry and spread the disease without being affected. It is a type of enteric fever, replicating only in humans.

Typhus: Typhus is a group of infectious diseases, including epidemic typhus, scrub typhus, and murine typhus. Symptoms of typhus include fever, headache, and rash, appearing one to two weeks after exposure.

Whooping cough: Whooping cough, or pertussis, is a highly contagious bacterial disease that can be prevented through vaccination. It starts with cold-like symptoms and progresses to severe coughing fits that can last for 10 weeks or more, accompanied by a high-pitched whooping sound. It may cause vomiting, rib fractures, and extreme fatigue. Infants may have difficulty breathing instead of coughing. The incubation period is usually 7-10 days, and even vaccinated individuals can still contract the disease, though their symptoms are usually milder.

Chickenpox: Chickenpox, or varicella, is a contagious disease caused by the varicella zoster virus. It manifests as an itchy skin rash with small blisters that scab over, starting on the chest, back, and face before spreading to the whole body. Symptoms include fever, tiredness, and headaches, which typically last for five to seven days. Although more severe in adults, complications such as pneumonia and inflammation of the brain can occur. Vaccination can prevent this disease.

Common cold: The common cold is a viral infection that primarily affects the upper respiratory tract. Symptoms, which can appear within two days of exposure, include coughing, sore throat, runny nose, sneezing, headache, and fever. Recovery usually takes about 7-10 days, but some symptoms may last up to three weeks. Pneumonia may develop in individuals with pre-existing health conditions.

Dengue fever: Dengue fever is a tropical disease transmitted by mosquitoes, causing symptoms like high fever, headache, vomiting, and joint pains. It is characterized by skin rashes and typically lasts 2-7 days. In some cases, it can escalate to severe dengue hemorrhagic fever or dengue shock syndrome, causing bleeding, low platelet levels, and dangerously low blood pressure.

Ebola: Ebola, also known as Ebola virus disease (EVD) and Ebola hemorrhagic fever (EHF), is a deadly viral illness that affects humans and primates. Symptoms start after 2 days to 3 weeks and include fever, sore throat, muscle pain, and headaches. This is followed by vomiting, diarrhea, rash, decreased liver and kidney function, and internal/external bleeding. Ebola has a high fatality rate, killing between 25%-90% of those infected. Death usually occurs within 6-16 days. Treatment is more effective when started early. An Ebola vaccine was approved by the US FDA in December 2019.

Hand, foot, and mouth disease: Hand, foot, and mouth disease (HFMD) is an infection caused by enteroviruses. It starts with a fever and feeling unwell, followed by spots or blisters on hands, feet, mouth, and sometimes buttocks and groin. Symptoms usually appear 3-6 days after exposure and the rash usually clears in a week. Temporary loss of fingernails and toenails may occur but will regrow.

Hepatitis: Hepatitis is an inflammation of the liver. Symptoms vary and can range from no symptoms at all to yellowing of the skin and eyes, fatigue, and abdominal pain. The condition can be acute, resolving within six months, or chronic, lasting longer. Acute hepatitis can resolve on its own, progress to chronic hepatitis, or rarely, lead to acute liver failure. Chronic hepatitis can lead to cirrhosis, liver failure, and liver cancer.

Herpes: Herpes is a viral infection caused by the herpes simplex virus, categorized by the infected body area. It includes oral and genital herpes, alongside other forms.

HIV/AIDS: HIV is a retrovirus that can cause AIDS. Treatment can manage HIV, but without it, a range of conditions can develop, including AIDS.

Human papillomavirus infection: Human papillomavirus (HPV) infection is caused by a DNA virus and often has no symptoms, resolving spontaneously in most cases. However, persistent infection can lead to warts or precancerous lesions. These lesions can increase the risk of cancers in various areas of the body, including the cervix, vulva, vagina, penis, anus, mouth, tonsils, and throat. HPV16 and HPV18 are responsible for the majority of cervical cancer cases, while HPV16 is also a common cause of oropharyngeal cancers. Additionally, HPV is linked to a significant number of other cancers, and HPV6 and HPV11 commonly cause genital warts and laryngeal papillomatosis.

Influenza: Influenza, also known as the flu, is an infectious disease caused by flu viruses. Symptoms range from mild to severe, including fever, runny nose, sore throat, muscle pain, headache, coughing, and fatigue. These symptoms usually appear 1-4 days after exposure and last around 2-8 days. In children, diarrhea and vomiting may occur. Influenza can lead to pneumonia or worsen pre-existing health problems like asthma and cardiovascular disease. Other complications may include acute respiratory distress syndrome, meningitis, and encephalitis.

Measles: Measles is a highly contagious disease caused by the measles virus. Symptoms appear 10-12 days after exposure and last for 7-10 days. Fever, cough, runny nose, inflamed eyes, and a red rash are common symptoms. Complications like diarrhea, ear infection, and pneumonia can arise due to weakened immune system. Measles can also lead to seizures, blindness, or brain inflammation. It is preventable with vaccination and should not be confused with rubella or roseola.

Mumps: Mumps is a viral disease that causes non-specific symptoms like fever, headache, muscle pain, and loss of appetite. It is characterized by painful swelling of the parotid glands, known as parotitis. Symptoms usually appear 16 to 18 days after exposure and last for about two weeks. One-third of cases do not display any symptoms.

Polio: Polio, short for poliomyelitis, is an infectious disease caused by the poliovirus. It mostly shows no symptoms, but mild ones like sore throat and fever can occur. Severe cases may experience symptoms like headache, neck stiffness, and paralysis, potentially leading to death. Some individuals may develop post-polio syndrome, resulting in gradual muscle weakness similar to the initial infection.

Rabies: Rabies is a deadly viral disease causing encephalitis in humans and animals. Its historical name, hydrophobia, refers to the fear of liquids due to panic symptoms. Early symptoms include fever and abnormal sensations. These progress to more severe symptoms such as vomiting, violent movements, fear of water, and loss of consciousness. Death is almost certain once symptoms appear, despite treatment. The time between infection and symptom onset is typically one to three months, but can vary. The virus travels along nerves to reach the central nervous system.

SARS: SARS is a severe respiratory disease caused by the SARS-CoV-1 virus, which originated from animals. It was first reported in November 2002, leading to a global outbreak lasting until 2004. Chinese scientists traced the virus from Asian palm civets to cave-dwelling horseshoe bats in Yunnan province.

Smallpox: Smallpox was caused by the variola virus and belonged to the Orthopoxvirus genus. It was eradicated in 1980 after the last known case in October 1977, making it the only human disease to be globally eradicated.

West Nile fever: West Nile fever is caused by the West Nile virus and is primarily transmitted by mosquitoes. 80% of people infected show minimal or no symptoms, while 20% experience fever, headache, vomiting, or a rash. Less than 1% develop encephalitis or meningitis, which can lead to neck stiffness, confusion, or seizures. Recovery can take weeks to months, and those with nervous system involvement face a 10% risk of death.

Yellow fever: Yellow fever is a viral infection that causes symptoms like fever, chills, loss of appetite, muscle pains, and headaches. Most people recover within five days, but in about 15% of cases, the fever returns along with abdominal pain and liver damage. This can lead to yellow skin, increased risk of bleeding, and kidney problems.

Coronavirus: Coronaviruses are RNA viruses that infect both mammals and birds, causing a range of respiratory tract infections. In humans, they can cause mild colds or more severe diseases like SARS, MERS, and COVID-19, which is currently causing a pandemic. They also cause diarrhea in cows and pigs, and hepatitis and encephalomyelitis in mice.

HIV: HIV is a Lentivirus that infects humans and leads to AIDS, a condition where the immune system fails, allowing life-threatening infections and cancers to occur. Without treatment, survival time after HIV infection is estimated to be 9 to 11 years, depending on the subtype.

Tobacco mosaic virus: The Tobacco mosaic virus (TMV) is a RNA virus that attacks a variety of plants, particularly tobacco. It causes distinct patterns of mottling and discoloration on leaves, resembling a mosaic. TMV was the first virus ever discovered and identified as a pathogen. It was crystallized by Wendell Meredith Stanley and it is similar in size to a large synthetic molecule called PG5.

Scabies: Scabies is a contagious skin infestation caused by a tiny mite called Sarcoptes scabiei. It leads to severe itchiness and a pimple-like rash, with possible appearance of burrows on the skin. Symptoms occur within weeks in first-time infections and within 24 hours in subsequent infections. It can affect various body parts, especially wrists, fingers, and waistline. Scratching can worsen the condition and lead to skin breakdown and bacterial infections.

Malaria: Malaria is a mosquito-borne disease that affects humans and other vertebrates. It causes symptoms like fever, fatigue, vomiting, and headaches. Severe cases can lead to jaundice, seizures, coma, or death. Symptoms usually appear 10-15 days after a mosquito bite and recurrence is possible if not properly treated. Recent survivors usually experience milder symptoms upon reinfection, but partial resistance fades without ongoing exposure.

Mental disorder: A mental disorder, also known as a mental illness or psychiatric disorder, is a behavioral or mental pattern that causes distress and impairs personal functioning. It is characterized by significant disturbances in cognition, emotional regulation, or behavior, occurring as single episodes or persistently. There are various types of mental disorders with unique signs and symptoms, all of which are part of mental health.

Anxiety disorder: Anxiety disorders are mental conditions marked by intense anxiety and fear, leading to impaired functioning in various aspects of life. Symptoms include restlessness, irritability, fatigue, difficulty concentrating, increased heart rate, and various other individual-specific manifestations.

Phobia: A phobia is an anxiety disorder where individuals experience persistent and excessive fear towards an object or situation. The fear often arises rapidly and continues for more than six months. Affected individuals take extreme measures to avoid the feared object or situation, going beyond the actual level of danger. If avoidance is not possible, they may feel significant distress. Phobias can be accompanied by symptoms like fainting and panic attacks. It is common for individuals with phobias to have multiple fears, with approximately 75% having more than one phobia.

Post-traumatic stress disorder: PTSD is a mental disorder caused by traumatic events. It leads to disturbing thoughts, distress, and avoidance of trauma-related cues. The way someone thinks and feels may also change, and the fight-or-flight response increases. Symptoms persist for over a month. Young children may express memories through play. Those with PTSD are at a higher risk of suicide and self-harm.

Attention deficit hyperactivity disorder: ADHD is a neurodevelopmental disorder causing excessive and pervasive inattention, hyperactivity, impulsivity, and emotional dysregulation. It impairs in multiple contexts and is age-inappropriate.

Autism spectrum: Autism, also known as autism spectrum disorder (ASD) or autism spectrum condition (ASC), is a neurodevelopmental disorder characterized by impaired social communication, restricted and repetitive behaviors, and difficulty with social interaction and communication. It includes perseverative interests, stereotypic body movements, rigid routines, and heightened or reduced sensitivity to sensory input. Autism is a spectrum disorder, meaning it presents differently in each individual, with variations in communication abilities and support needs.

Eating disorder: An eating disorder is a mental disorder characterized by unhealthy eating behaviors that harm a person's physical and mental health. Types of eating disorders include binge eating, anorexia, bulimia, pica, rumination syndrome, and avoidant/restrictive food intake disorder (ARFID). Anxiety disorders, depression, and substance abuse often coexist with eating disorders. It is estimated that 20-60% of those with an eating disorder also have a history of OCD.

Bipolar disorder: Bipolar disorder, also known as manic depression, is a mental disorder characterized by alternating periods of depression and abnormally elevated mood, known as mania or hypomania. During manic phases, individuals exhibit excessive energy, impulsivity, and decreased need for sleep. Depression is marked by low mood, negative outlook, and a heightened risk of suicide. Bipolar disorder is often associated with other mental health issues like anxiety and substance use disorders.

Major depressive disorder: Major depressive disorder (MDD), or clinical depression, is a mental disorder characterized by persistent low mood, diminished self-esteem, and a lack of interest in activities. It was introduced by US clinicians in the 1970s and later adopted by the American Psychiatric Association. MDD is a widely recognized condition in the field of mental health.

Pedophilia: Pedophilia is a psychiatric disorder where adults or older adolescents have a primary sexual attraction to prepubescent children. It is diagnosed based on the age of attraction being younger than 13. Individuals with this disorder are commonly called pedophiles.

Personality disorder: Personality disorders are mental disorders characterized by ongoing patterns of unhealthy behavior, thinking, and inner experiences that deviate from culturally accepted norms. These patterns are inflexible, develop early in life, and cause significant distress or impairment. The official criteria for diagnosis can be found in the ICD and DSM manuals.

Psychopathy: Psychopathy is a mental condition marked by long-lasting antisocial behavior, diminished empathy and remorse, and bold, impulsive, and narcissistic characteristics. Over time, varying interpretations of psychopathy have emerged, with some similarities and occasional inconsistencies.

Schizophrenia: Schizophrenia is a mental disorder characterized by recurring episodes of psychosis that cause a distorted perception of reality. It includes symptoms like hallucinations, delusions, disorganized thinking, social withdrawal, and flat affect. Diagnosis is made based on observed behavior, psychiatric history, and reports from others. Symptoms typically appear during young adulthood and have no cure. Substance use, depression, anxiety, and obsessive-compulsive disorder often coexist with schizophrenia.

Neurosis: Neurosis refers to mental disorders resulting from repressed past anxiety. It is commonly used to describe anxiety-related conditions in general.

Diarrhea: Diarrhea is the condition of experiencing three or more loose, watery bowel movements per day. It typically lasts a few days, leading to dehydration due to fluid loss. Signs of dehydration include dry skin, irritability, decreased urination, pale skin, rapid heart rate, and reduced responsiveness. Exclusive breastfed babies may have loose but non-watery stools, which is considered normal.

Inflammation: Inflammation is a protective response of body tissues to harmful stimuli, aiming to eliminate the cause of cell injury, remove damaged cells, and initiate tissue repair. It involves immune cells, blood vessels, and molecular mediators.

Psychosis: Psychosis is a mind condition causing trouble distinguishing reality. Symptoms include delusions, hallucinations, incoherent speech, and inappropriate behavior. It may also result in sleep problems, social withdrawal, lack of motivation, and difficulties with daily activities. Psychosis can have severe consequences.

Delusion: A delusion is a false and unchanging belief that does not respond to contradicting evidence. It differs from beliefs based on misinformation as those can be adjusted when presented with new evidence.

Hallucination: A hallucination is a perception without an external stimulus that resembles a real perception. It combines wakefulness and REM sleep states. Hallucinations are vivid and solid, appearing to be in external space. They can be distinguished from dreaming, pseudohallucinations, illusions, and mental imagery. They are also different from delusional perceptions, where a sensed stimulus is given extra meaning.

Toothache: Toothache refers to dental pain caused by dental or non-dental diseases, affecting the teeth and surrounding structures. Severe toothache can disrupt sleep, eating, and daily activities.

Health: Health refers to the state of well-being, with various definitions used for different purposes. It can be enhanced by promoting healthy habits like exercise and quality sleep while avoiding unhealthy behaviors like smoking and excessive stress. Some health factors stem from personal choices, while others are influenced by societal structures and access to healthcare services. Genetic disorders also play a role in individual and collective health.

Mental health: Mental health refers to the overall well-being of an individual, encompassing emotional, psychological, and social aspects. It affects cognition, perception, behavior, and the ability to cope with stress and maintain relationships. It involves subjective well-being, self-efficacy, autonomy, competence, and the realization of one's potential. Mental health also includes the ability to enjoy life and achieve psychological resilience. Cultural differences, personal philosophy, and subjective assessments impact how it is defined. Early signs of mental health difficulties include sleep problems, lack of energy, appetite changes, thoughts of self-harm or harm to others, social withdrawal, and zoning out frequently.

Physical fitness: Physical fitness refers to the state of being healthy and capable of participating in sports, work, and daily tasks. Achieving physical fitness involves maintaining a nutritious diet, engaging in regular and moderate to intense physical activity, resting adequately, and adhering to a structured recovery plan.

Body mass index: The body mass index (BMI) is a measure of an individual's weight in relation to their height, calculated by dividing their weight (in kg) by the square of their height (in m). It provides a numerical representation of a person's body composition and is expressed in units of kg/m2.

Exercise: Exercise is intentional physical activity for improving or maintaining fitness and overall health.

Obesity: Obesity is a medical condition where excessive body fat accumulates, potentially harming health. It is determined by a body mass index (BMI) over 30 kg/m2, with a range of 25-30 kg/m2 considered overweight. Obesity is associated with various health issues, including cardiovascular diseases, type 2 diabetes, sleep apnea, cancer, and osteoarthritis.

Weight loss: Weight loss is the reduction of body mass, achieved by losing fluid, body fat, or lean mass. It can occur unintentionally due to malnourishment or a disease, or intentionally to improve overweight or obesity. Unexplained weight loss not caused by diet or exercise can indicate a severe medical condition known as cachexia.

Ageing: Ageing, the process of becoming older, primarily affects humans, animals, and fungi. Some organisms like bacteria, perennial plants, and certain simple animals may be biologically immortal. Ageing can also refer to individual cells that have stopped dividing or to the entire population of a species.

Breastfeeding: Breastfeeding, or nursing, is the process of feeding a child with human breast milk. It is recommended by the World Health Organization to start within the first hour of a baby's life and continue as often as the baby wants. Exclusive breastfeeding for the first 6 months is advised, with the introduction of complementary foods after that. However, a significant number of babies are not breastfed within the first hour, mothers do not practice exclusive breastfeeding for 6 months, and not all mothers continue breastfeeding up to 2 years and beyond.

Fertilisation: Fertilisation is the fusion of gametes, leading to the creation of a new organism and its development. It is also known as generative fertilisation, syngamy, and impregnation. Insemination and pollination are sometimes referred to as fertilisation, but technically they are different processes. This is part of the sexual reproduction cycle. In angiosperms, double fertilisation involves the combination of a male gamete with two polar nuclei to form a triploid endosperm nucleus.

Infertility: Infertility is the inability to reproduce naturally for animals or plants. While it is abnormal for healthy adults, some eusocial species may experience infertility. Infertility is common in human children and young offspring due to their pre-puberty stage before reproductive capacity begins.

Nutrition: Nutrition is the process of using food to sustain life, providing organisms with nutrients for energy and chemical structures. Lack of adequate nutrients leads to malnutrition. Nutritional science focuses on studying nutrition, primarily human nutrition.

Diet (nutrition): Diet refers to the food consumed by an individual or organism, with emphasis on specific nutrition for health or weight management. Food preferences and taboos vary across cultures and individuals, influenced by personal taste or ethical beliefs. It's important to note that dietary choices can vary in their level of healthiness.

Dietary supplement: A dietary supplement is a manufactured product in pill, capsule, tablet, powder, or liquid form that is taken to supplement one's diet. It can provide nutrients from food sources or synthetic sources. These supplements can contain vitamins, minerals, fiber, fatty acids, and amino acids. Some supplements also include substances that are not essential nutrients but are marketed as having health benefits, such as plant pigments or polyphenols. Animal sources can also be used, such as collagen from chickens or fish. Supplements can be sold individually or in combination and may be combined with other nutrient ingredients. The European Commission has established rules to ensure the safety and appropriate labeling of food supplements.

Food group: A food group is a category of foods with similar nutritional values or biological classifications. Nutrition guides divide foods into groups, and daily servings from each group are recommended for a healthy diet. The USDA in the United States defines food into 4 to 11 groups.

Hunger: Hunger refers to the condition where individuals lack the ability to obtain enough food necessary for basic nutritional needs over an extended period. In the context of hunger relief, it goes beyond a simple desire for food. Severe hunger can lead to malnutrition, starvation, and ultimately, famine.

Malnutrition: Malnutrition refers to a lack or excess of nutrients that adversely affects the body's tissues and form. It can lead to health issues and is commonly observed in children under five years old due to insufficient access to adequate nutrition.

Vitamin: Vitamins are essential organic molecules that organisms need in small amounts for proper metabolism. They cannot be made by the body in sufficient quantities and must be obtained through diet. Some vitamins, like vitamin C, can be synthesized by certain species but not others. Most vitamins exist as groups of related molecules called vitamers.

Occupational safety and health: Occupational safety and health (OSH) is a multidisciplinary field that focuses on ensuring the safety, health, and welfare of people at work. It includes occupational medicine and occupational hygiene. OSH aims to create a safe working environment and prevent work-related injuries and illnesses.

Substance use disorder: Substance use disorder (SUD) is a treatable mental illness where individuals continue to use drugs despite harmful effects. It affects the brain and behavior, leading to an inability to control substance use. Symptoms range from moderate to severe, with addiction being the most extreme form. SUD varies based on age of onset, duration, and type of substance used. Co-occurring mental health disorders are common. SUD is characterized by emotional, physical, and behavioral issues such as guilt, unsuccessful attempts to quit, impaired driving, and withdrawal symptoms. Common substances involved include alcohol, cannabis, opioids, stimulants, benzodiazepines, and others.

Addiction: Addiction is a disorder characterized by a strong desire to use drugs or engage in rewarding behavior, despite harmful consequences. Continued drug use can alter brain function and weaken self-control. Addiction is considered a brain disorder with various psychological and biological factors involved. Common signs include compulsive behavior, preoccupation, and continued use despite negative outcomes. Addictive habits often bring immediate pleasure but can have delayed negative effects.

Alcoholism: Alcoholism, or the problematic use of alcohol, refers to the persistent consumption of alcohol despite negative consequences. It has been recognized throughout history and continues to affect a significant number of people worldwide. The term "alcoholism" was coined in 1852, but alternative clinical terms like "alcohol use disorder" are now preferred to reduce stigma and encourage treatment-seeking behavior.

Substance dependence: Substance dependence, also known as drug dependence, occurs when an individual's functionality relies on repeatedly using a psychoactive substance due to an adaptive state that develops from consumption, resulting in withdrawal symptoms and the need for further drug use. Different from dependence, drug addiction involves compulsive and uncontrollable drug use, despite negative consequences. Addictive drugs are rewarding and reinforcing. ΔFosB, a gene transcription factor, plays a crucial role in the development of various behavioral and drug addictions, but not dependence.

Smoking: Smoking is the act of inhaling combusted substances, mainly tobacco leaves rolled into cigarettes, to introduce the smoke into the bloodstream. Other methods involve smoking pipes and bongs.

Cigarette: A cigarette is a thin cylinder of tobacco rolled in paper for smoking. It is ignited at one end and the resulting smoke is inhaled through the other end. Cigarette smoking is the main way tobacco is consumed. The term is often used specifically for tobacco cigarettes but can refer to other substances as well. Cigarettes are smaller than cigars, use processed leaf, and have a white paper wrapping. Many cigarettes are filtered, but this doesn't reduce the harmful chemicals and carcinogens in the smoke.

Stress (biology): Stress is an organism's response to environmental conditions, and it can be physiological, biological, or psychological. The body reacts to stress by releasing hormones like adrenaline and cortisol. These hormones have two types of levels: resting levels, which are necessary for normal functioning, and reactive levels, which increase in response to stress. Various systems in the body, such as the autonomic nervous system and the hypothalamic-pituitary-adrenal axis, respond to stress.

Hygiene: Hygiene is a practice aimed at safeguarding health and preventing diseases. It encompasses various types, such as personal, medical, sleep, and food hygiene. Personal hygiene includes maintaining body cleanliness, while medical hygiene is practiced at home. Home and everyday hygiene involve tasks like hand washing, respiratory hygiene, and maintaining cleanliness in the kitchen and bathroom. Additionally, food hygiene at home and laundry hygiene are essential for maintaining health.

Bathing: Bathing refers to the act of cleaning the body with water or immersing oneself in water. It serves multiple purposes, including personal hygiene, religious and therapeutic practices. Additionally, the term encompasses recreational activities like sun bathing and sea bathing.

Feminine hygiene: Feminine hygiene refers to personal care products used for menstruation, vaginal discharge, and other functions related to the vulva and vagina. These products include menstrual pads, tampons, pantyliners, menstrual cups, sponges, and period panties. Additionally, feminine hygiene products also encompass items used to cleanse the vulva or vagina, such as douches, wipes, and soap.

Oral hygiene: Oral hygiene involves keeping the mouth clean and healthy through regular brushing and good hygiene habits. It prevents dental diseases like tooth decay and gum diseases such as gingivitis and periodontitis. Regular practice is essential to prevent dental issues and bad breath.

Shaving: Shaving refers to the act of removing hair by cutting it with a razor or similar implement. It is commonly practiced by men to remove facial hair and by women to remove hair from their legs and underarms. When a man completely removes his beard, he is considered clean-shaven.