5.    Which of the following  is  an ecosystem?

        a. decomposers          b. sunlight         c. a fish         d. the planet earth

An ecosystem is an arbitrally defined geographic area ( a terrarium, the Mississippi River, the Gobi desert, etc.)  that consists of biotic and abiotic components.  Ecology is concerned with the interactions among all of the biotic and abiotic components of the ecosystem.    Decomposers and fish are examples of biotic components and sunlight is an abiotic component.       

home13.gif (1441 bytes)BIOWEB  home13.gif (1441 bytes)Al BIO 101 Web Section  home13.gif (1441 bytes)ELI BIO 101 Web Section 
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Emma Erdahl, Associate Professor of Biology
Northern Virginia Community College
Revised 8/23/00