Food Web and Food Chain (Encyclopedia of Science)
The terms food chain and food web both refer to groups of organisms that are dependent on each other for food. A food chain is a single series of organisms in which each plant or animal depends on the organism above or below it. As an example, a food chain might consist of garden plants, such as lettuce and carrots, fed upon by rabbits which, in turn, are fed upon by owls which, in turn, are fed upon by hawks.
A food chain is largely a theoretical idea and probably seldom, if ever, exists in the real world. It is a useful concept, however, as it helps ecologists understand how specific plants and animals are dependent upon one another.
The feeding relationships of organisms in the real world is almost always more complex than suggested by a food chain. For that reason, the term food web is more accurate than is food chain. A food web differs from a food chain in that it includes all the organisms whose feeding habits are related in some way or another to those of other organisms. In the example above, small animals other than rabbits feed on lettuce and carrots and, in turn, those animals are fed upon by a variety of larger animals.
Structure of food webs
Food webs are organized into three main categories, depending on the kinds of organisms they contain. These three categories are known as trophic levels. The three...
(The entire section is 1432 words.)
Want to Read More?
Subscribe now to read the rest of this article. Plus get complete access to 30,000+ study guides!