Question

Define food chain. How many types of food chain are there ? Give difference between food chain and food web. Draw a linear diagram of food chain.

Answer 1

The food chain is the sequence of organisms through which food and energy are passed in an ecosystem with the members of trophic level.

There are two types of a food chain.

(i) Detritus food chain always starts with the dead organic material. Food energy pass into decomposers and detrivores, which are further consumed by smaller carnivores, like maggots, which in turn become food for larger carnivores, like a frog and further to snake and so on.

(ii) A grazing food chain always starts with the living green plants and goes to herbivores and on to carnivores. It is directly dependent on a solar radiation. This type of chain depends on autotrophic energy capture and the movement of this energy to herbivores. Most of the ecosystems in nature follow this type of food chain.

A food chain is a linear sequence which represents who is eating who. Here, organisms of higher trophic level derive its nutrients from organisms of a lower trophic level. A food web is a network of food chains, which are interconnected at different trophic level. More the number of cross-connections between different food chains, more complex will be the food web and greater will be the stability of the ecosystem.