Home > Encyclopedia of Science > Food Web and Food Chain

• Structure of food webs
• Words to Know
• Ecological pyramids
• Biomagnification

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...