Q.5 Explain Flow of Materials in an Ecosystem.
Answer:
Introduction
The materials flow from one trophic level to the next by means of food chains and food webs. Food Chain
A food chain is a series of organisms within an ecosystem, in which each organism feeds on the one before it and is fed by one after it. Example
Grass ———— Grasshopper ———– Sparrow ———– Hawk

The base of food chain is always formed by a producer. It is eaten by a primary consumer, which is preyed upon by secondary consumer. The secondary consumer may be eaten by a tertiary. consumer. A food chain, can therefore, be represented as,
Producer———- Primary Consumer———— Secondary Consumer———– Tertiary
Consumer
A food chain involves a nutritive interaction among the biotic components of an ecosystem. Usually there are 4 or 5 trophic levels. Shorter food chains provide greater available energy and vice – versa.
Food Web
In nature, food chains are very complex, as one organism may be the food source of many other organisms. So there is a web like structure formed by these interlinked food chains. Such interconnected food chains collectively make food web.
OR
It may also be defined as, “a network of food chains which are interconnected at various trophic. levels”.