chapter  2
14 Pages

Organisms and Environmental Factors

Every living organism is an open system that exchanges matter and energy with the environment. In various ways the organism takes all the chemical substances it needs for the composition of its body from the environment and casts off into the environment the substances that are no longer useful for its functions. In addition, the organism takes from the environment energy in appropriate forms, which it uses to carry out the chemical reactions of synthesis, to move about, and to regulate its temperature; it casts off energy into the environment, mainly in the form of heat.