Food chains in natural conditions never operate as isolated sequences, but are interconnected with each other forming some sort of interlocking pattern. Many animals, in nature, utilize more than one species for their food. Herbivores feed on different kinds of plants. Carnivores feed on different kinds of herbivores; so also birds feed on different kinds of insect sand animals.
Thus, the food chains in nature are interconnected in different ways, invariably with a number of intermediate links and sometimes with side chains also and such interconnected food chains are called food webs.
1. Various food chains are interlinked at different trophic levels to form a complex interaction between different species from the point of view of food.
“Food web is a network of food chains.”
If any of the intermediate stage of the food chain is removed, the succeeding links of the food chain will be affected.
2. The food web provides more than one alternatives of food to most of the organisms in an ecosystem and that to increases their chances of survival.
3. Food web gives greater stability to the ecosystem.
Example: The food web in a forest community.
In such a food web in the forest community, there may be seen as many as four food chains. The rodent feed on the products of green plants these rodents are eaten by snakes,’ which in turn are eaten by hawks.
The ungulates feed on green plants. These ungulates are I hunted and eaten by rabbits which in turn are eaten either by hawks or by lions and tigers. Many insects feed on green plants and their products.
These insects are eaten by lizards, which are eaten by hawks. The insects are also swallowed by frogs, which in turn can be captured and eaten by hawks. Here hawks, lions and tigers occupy the top of the food web.
Significance of Food Chain and Food Webs
1. Energy flow and nutrient cycling take place through them.
2. Food chain helps in maintaining and regulating the population size of different organisms.
It maintains the ecological balance by some chemicals (chemicals which are not decomposed by microorganisms possess from one trophic level to another level).