food chain The transfer of energy from green plants (the primary producers) through a sequence of organisms in which each eats the one below it in the chain and is eaten by the one above. Thus plants are eaten by herbivores, which are then eaten by carnivores. These may in turn be eaten by different carnivores. The position an organism occupies in a food chain is known as its trophic level. In practice, many animals feed at several different trophic levels, resulting in a more complex set of feeding relationships known as a food web. See bioenergetics; consumer; producer; pyramid of biomass; pyramid of energy; pyramid of numbers.

food-chain The transfer of energy from the primary producers (green plants) through a series of organisms that eat and are eaten, assuming that each organism feeds on only one other type of organism (e.g. earthworm → blackbird → sparrowhawk). At each stage much energy is lost as heat, a fact that usually limits the number of steps (trophic levels) in the chain to four or five. Two basic types of food-chain are recognized: the grazing and detrital pathways. In practice these interact to give a complex food-web.

food chain The transfer of energy from the primary producers (green plants) through a series of organisms that eat and are eaten, assuming that each organism feeds on only one other type of organism (e.g. earthworm → blackbird → spar-rowhawk). At each stage much energy is lost as heat, a fact that usually limits the number of trophic levels in the chain to four or five. Two basic types of food chain are recognized: the grazing and detrital pathways. In practice chains interact to give a complex food web.

food-chain efficiency The ratio between the energy value (the nutritional value, discounting indigestible parts such as hair or feathers) of prey consumed by a predator and the energy value of the food eaten by that prey. Maximum food-chain efficiency (gross ecological efficiency) occurs when the yield of prey to the predator is such that the surviving prey just consume all the available food: this implies that the food of the prey is being exploited to the best advantage by the predator.

food-chain efficiency The ratio between the energy value (the nutritional value, discounting indigestible parts such as hair or feathers) of prey consumed by a predator and the energy value of the food eaten by that prey. Maximum food-chain efficiency (gross ecological efficiency) occurs when the yield of prey to the predator is such that the surviving prey just consume all the available food: this implies that the food of the prey is being exploited to the best advantage by the predator.

food-chain efficiency The ratio between the energy value (the nutritional value, discounting indigestible parts such as hair or featehrs) of prey consumed by a predator and the energy value of the food eaten by that prey. Maximum food-chain efficiency (gross ecological efficiency) occurs when the yield of prey to the predator is such that the surviving prey just consume all the available food: this implies that the food of the prey is being exploited to the best advantage by the predator.

food chain Transfer of energy through a series of organisms, each organism consuming the previous member of the chain. Its main sequence is from green plants (producers) to herbivores (primary consumers) and then to carnivores (secondary consumers). Decomposers, such as bacteria and fungi, act at each stage, breaking down waste and dead matter into forms that can be absorbed by plants, thus perpetuating the chain. See also decomposition; photosynthesis

food-chain The transfer of energy from the primary producers (green plants) through a series of organisms that eat and are eaten. At each stage much energy is lost as heat, a fact that usually limits the number of steps (trophic levels) in the chain to 4 or 5. Two basic types of food-chain are recognized: the grazing and detrital pathways. In practice, these interact to give a complex food-web.

food chain The chain between green plants (the primary producers of food energy) through a sequence of organisms in which each eats the one below it in the chain, and is eaten in turn by the one above. Also used for the chain of events from the original source of a foodstuff (from the sea, the soil, or the wild) through all the stages of handling until it reaches the table.

food chain • n. a hierarchical series of organisms each dependent on the next as a source of food.

food chain: see ecology.