ENVIRONMENTAL STUDIES(ES)

ENVIRONMENTAL STUDIES

Lesson 12: Food chains, food webs and ecological pyramids

Food web

Interlocking pattern of food chains is called food web. In the ecosystem, food chains are not isolated. Food relationships exist among different biotic components as well as between food chains involving them. “A network of food chains interconnected at various trophic levels forming many connections among different organisms of a community is referred to as a food web. A food web opens many alternate pathways for energy flow. It also allows an organism to obtain nutrition from more than one type of organisms. There are five linear food chains in the food web of a grass land.

All these five chains are interlinked with each other at different points forming a food web. The food webs are important in maintaining the stability of an ecosystem in nature. For eg. Decrease in the population of rabbit would naturally cause an increase in the population of alternative herbivore, the mouse. This may decrease the population of the consumer that prefers to eat rabbit.

Thus food chains and food webs form a natural check to balance the ecosystem. The complexity of any food web depends upon biodiversity of the system. The biodiversity is based on a) length of the food chain b) alternatives in the length of the food chain.