Food chains

To understand the workings of a food web, it is first necessary to look at the more commonly known food chain which displays the direct, step-by-step feeding connections between a given series of animals. Food chains help improve comprehension of simple links between various species.

Food webs

Since animals eat and are fed upon by many different species, food chains rarely exist independently. A food web gives a more integrated picture of a given environment. As the name suggests it can be visualized as a series of food chains that, when linked and woven together, fully describe an ecosystem.

Levels

Food diagrams contain a hierarchy of three levels. At the bottom are producers which manufacture their own food. Next are consumers which eat producers and other consumers to survive. Finally, there are decomposers, which feed off the dead of the other two groups.

Limits

Both food webs and chains have a practical limit of a few steps since food energy tends to diminish as it moves up the hierarchy. In most instances an animal is only able to absorb about one-tenth of the food energy it takes in. This shrinkage means that by the fourth link in the chain, only about a tenth of one percent of the original energy is left.

History

Ecologist Charles Elton is credited with the creation of the food web in the early Twentieth Century. He originally called it a "food cycle."

Source:

Science Clarified - Food web and food chain

Encyclopedia of Earth - Food web

More Information:

Pacific Ecoinformatics and Computational Ecology Lab