Like this study set? Create a free account to save it.

Sign up for an account

Already have a Quizlet account? .

Create an account


the regions of the surface and atmosphere of the Earth (or other planet) where living organisms exist


a group of organisms of the same species populating a given area


(biology) taxonomic group whose members can interbreed


(ecology) a group of interdependent organisms inhabiting the same region and interacting with each other


the branch of biology concerned with the relations between organisms and their environment


a system formed by the interaction of a community of organisms with their physical environment


group of ecosystems that have the same climate and dominant communities

biotoc factor

biological influence on organisms within an ecosystem

abiotic factor

physical, or nonliving, factor that shapes an ecosystem


plant capable of synthesizing its own food from simple organic substances

primary producer

Organisms that produce energy available for other organisms to eat


synthesis of compounds with the aid of radiant energy (especially in plants)


synthesis of carbohydrate from carbon dioxide and water


an organism that depends on complex organic substances for nutrition


any animal that feeds on refuse and other decaying organic matter


a person who eats all kinds of foods


organisms that break down wastes and dead organisms and return raw materials to the environment


organism that feeds on plant and animal remains and other dead matter

Food chain

(ecology) a community of organisms where each member is eaten in turn by another member


small photosynthetic organisms found near the surface of the ocean

Food web

(ecology) a community of organisms where there are several interrelated food chains


animal constituent of plankton

Trophic level

each step in a food chain or food web

Ecological pyramid

diagram that shows the relative amounts of energy or matter within each trophic level in a food chain or food web


the total mass of living matter in a given unit area

Biogeochemical cycle

process in which elements, chemical compounds, and other forms of matter are passed from one organism to another and from one part of the biosphere to another


any substance that can be metabolized by an organism to give energy and build tissue

Nitrogen fixation

process in which bacteria convert nitrogen gas into nitrogen compounds plants can use to make proteins


conversion of nitrates into nitrogen gas

Limiting nutrient

single nutrient that either is scarce or cycles very slowly, limiting the growth of organisms in an ecosystem

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions and try again


Reload the page to try again!


Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

Voice Recording