Advertisement Upgrade to remove ads


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


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


plant capable of synthesizing its own food from simple organic substances


synthesis of carbohydrate from carbon dioxide and water


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


the total mass of living matter in a given unit area


When a plant releases water into the atmosphere


conversion of nitrates into nitrogen gas


a major biotic community characterized by the dominant forms of plant life and the prevailing climate

Trophic Level

each step in a food chain or food web

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 above 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

NEW! Voice Recording