(Ecology) A community of organisms where each member is eaten in turn by another member.
In ecology, a sequence showing the feeding relationships between organisms in a particular ecosystem. Each organism depends on the next lowest member of the chain for its food.
Energy in the form of food is shown to be transferred from autotrophs, or producers, which are principally plants and photosynthetic microorganisms, to a series of heterotrophs, or consumers. The heterotrophs comprise the herbivores, which feed on the producers; carnivores, which feed on the herbivores; and decomposers, which break down the dead bodies and waste products of all four groups (including their own), ready for recycling.
In reality, however, organisms have varied diets, relying on different kinds of foods, so that the food chain is an oversimplification. The more complex food web shows a greater variety of relationships, but again emphasizes that energy passes from plants to herbivores to carnivores.
Environmentalists have used the concept of the food chain to show how poisons and other forms of pollution can pass from one animal to another, threatening rare species. For example, the pesticide DDT has been found in lethal concentrations in the bodies of animals at the top of the food chain, such as the golden eagle Aquila chrysaetos.