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Updated Biology Courses cardella

General Biology
Prof. Bryan Cardella, M.Ed.

ap biology eaton

AP Biology 
Dr. Carleen Eaton, M.D.

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  • Study Guides

Chemical Element Cycles

  • While energy flows through an ecosystem and must be constantly supplied, chemical elements are recycled. As an element moves through an ecosystem, it may cycle between several different chemical forms.

  • Not all chemical forms are usable by all organisms. It is the job of particular organisms in an ecosystem to convert the chemicals into usable forms.

  • In this Lesson, we'll look at the cycling of three important elements for biological organisms: carbon, nitrogen, and phosphorus. We'll also explore how human activities are altering the balance of certain chemicals in our environment.