Food Chain/Web

Food web research is an extensive area of ecological research. Charles Elton, Raymond Lindeman, Stuart Pimm, Stephen Carpenter, and James Kitchell are some of the major figures in food web research. Charles Elton was an English ecologist who first described the characteristic shape of food webs, which he called the pyramid of numbers. Elton observed that most food webs have many organisms on their bottom trophic levels and successively fewer on the subsequent, higher levels. His pyramid of numbers is now called the Eltonian Pyramid and is the basic model used to describe all food webs.

The American ecologist Raymond L. Lindeman published a classic paper in 1942 that examined the Eltonian pyramid in terms of energy flow. By using energy as the currency of the ecosystem Linderman quantified and explained that the Eltonian Pyramid was a result of successive energy losses at each trophic level. This loss is due to thermodynamic inefficiency in the transformation of energy and is referred to as ecological efficiency. Later, researchers discovered that ecological efficiency varies from 5-30% with an average of about 10%, depending on the species and the environment in which it lives.

Stuart Pimm published his classic book Food Webs in 1982. This book consolidated various aspects of food web theory and has become a reference for ecologists. The book's many topics include food web complexity and stability and hypotheses on food chain length.

More recently, Stephen Carpenter and James Kitchell have become leaders in aquatic food web research. Their theory regarding the trophic cascade in aquatic food webs has been central to the current debate on top-down and bottom-up control of food webs.