A Glossary of Zoology Terms

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This glossary defines terms that you might encounter when studying zoology.


An autotroph is an organism that obtains its carbon from carbon dioxide. Autotrophs need not feed on other organisms since they can synthesize the carbon compounds they need for energy-using sunlight and carbon dioxide.


The term binocular refers to a type of vision that arises from the ability of an animal to view an object with both eyes at the same time. Since the view from each eye is slightly different, animals with binocular vision perceive depth with great precision. Binocular vision is often characteristic of predator species such as hawks, owls, cats, and snakes. Binocular vision offers predators precise visual information needed to spot and capture their prey. In contrast, many prey species have eyes positioned on either side of their head. They lack binocular vision but instead have a wide field of view that helps them spot approaching predators.

Deoxyribonucleic acid (DNA)

Deoxyribonucleic acid (DNA) is the genetic material of all living things (except viruses). Deoxyribonucleic acid (DNA) is a nucleic acid that occurs in most viruses, all bacteria, chloroplasts, mitochondria, and the nuclei of eukaryotic cells. DNA consists of a deoxyribose sugar in each nucleotide. 


An ecosystem is a unit of the natural world that includes all the parts and interactions of the physical environment and the biological world.


Ectothermy is the ability of an organism to maintain its body temperature by absorbing heat from its environment. They obtain heat either via conduction (by laying on warm rocks and absorbing the heat through direct contact, for example) or by radiant heat (by warming themselves in the sun).

Groups of animals that are ectothermic include reptiles, fishes, invertebrates, and amphibians.

There are some exceptions to this rule though, some organisms belonging to these groups do maintain their body temperature above that of the surrounding environment. Examples include mako sharks, some sea turtles, and tuna.

An organism that employs ectothermy as a means of maintaining its body temperature is referred to as an ectotherm or is described as ectothermic. Ectothermic animals are also called cold-blooded animals.


An endemic organism is an organism that is restricted to, or native to, a specific geographical region and is not naturally found anywhere else.


The term endothermy refers to the capacity of an animal to maintain its body temperature by the metabolic generation of heat.


The environment consists of the surroundings of an organism, including the plants, animals, and microbes with which it interacts.


A frugivore is an organism that relies on fruit as a sole source of food.


 A generalist is a species that has broad food or habitat preferences.


Homeostasis is the maintenance of constant internal conditions despite a varying external environment. Examples of homeostasis include the thickening of fur in winter, the darkening of the skin in sunlight, the seeking of shade in the heat, and the production of more red blood cells at high altitude are all examples of adaptations animals make in order to maintain homeostasis.


A heterotroph is an organism that is unable to obtain its carbon from carbon dioxide. Instead, heterotrophs obtain carbon by feeding on the organic material present in other organisms, living or dead.

All animals are heterotrophs. Blue whales feed on crustaceans. Lions eat mammals such as wildebeest, zebras, and antelope. Atlantic puffins eat fish such as sandeel and herring. Green sea turtles eat seagrasses and algae. Many species of corals are nourished by zooxanthellae, tiny algae that live within the corals' tissues. In all of these cases, the animal's carbon comes from ingesting other organisms.

Introduced Species

An introduced species is a species that humans have placed into an ecosystem or community (either accidentally or intentionally) in which it does not naturally occur.


Metamorphosis is a process that some animals go through in which they change from an immature form to an adult form.


A nectivorous organism is one that relies on nectar as its sole source of food.


A parasite is an animal that lives on or within another animal (referred to as the host animal). A parasite either feeds on its host directly or on the food that the host ingests. In general, parasites tend to be much smaller than their host organisms. Parasites benefit from the relationship with a host while the host is weakened (but usually not killed) by the parasite.


A species is a group of individual organisms that are can interbreed and give rise to fertile offspring. A species is the largest gene pool that exists in nature (under natural conditions). If a pair of organisms are capable of generating offspring in nature, then they by definition belong to the same species.

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Klappenbach, Laura. "A Glossary of Zoology Terms." ThoughtCo, Apr. 5, 2023, thoughtco.com/glossary-of-zoology-terms-130928. Klappenbach, Laura. (2023, April 5). A Glossary of Zoology Terms. Retrieved from https://www.thoughtco.com/glossary-of-zoology-terms-130928 Klappenbach, Laura. "A Glossary of Zoology Terms." ThoughtCo. https://www.thoughtco.com/glossary-of-zoology-terms-130928 (accessed May 30, 2023).