The food chain

What is a food chain?

food chains represent the direct and indirect connection of the food relations in a –¶cosystem. The individual organisms are classified in terms of their trophic level in the material cycle in the three groups producers, consumers and destructors. Within this must be differentiated more exactly, for example between consumers I, II and III order.
The following example shows a simplified food chain in a terrestrial ecosystem:

At the beginning of each food chain are the autotrophic producers. Their enormous biomass is used in the ecosystems as a basis for primary consumers. In this example the caterpillar feeds on leaves of plants. The caterpillar, in turn, is eaten by carnivorous secondary consumers (fruit). At the end of this food chain is the eagle, a carnivorous bird of prey. He nourishes himself as a tertiary consumer of other, smaller consumers.
Incidentally, this exemplary food chain also does not constitute a definitive conclusion. It would be quite possible to add more consumers, e.g. another small bird of prey, which feeds on frogs and at the same time is on the menu of the eagle. In this case, the eagle would then be 4th order consumer.
In contrast to food webs, food chains only represent the compounds one-dimensionally-linearly. Therefore, food chains do not say anything about the ecological reality, because the organisms in a –¶cosystem usually feed on more than one prey animal.