2. For an organism to survive,food must be produced and made available in its own ecosystem.All the animals in the ecosystem are the heterotrophs.They depend on plants which are autotrophs.

3. An ecosystem consists of primary producers- are plants These are only organisms capable of carrying out photosynthesis and producing food in ecosystem. Ecosystem---Photosynthesis

4. Herbivores are consumers of plants as their food.Therefore these are called primary consumers of the ecosystem.cattle, rabbits and deer etc.

5. Some of the carnivores present in the ecosystem consume the herbivores as their food.These are called secondary consumers Wolf that eat rabbits in forests,frogs that eat herbivorous insects are examples.

6. These secondary consumers, in turn become food for other carnivores.They are called tertiary consumers.Birds eat fish. Snakes eat frogs

7. Food chain consists of primary producers, primary consumers, secondary consumers and tertiary consumers,one becomes food for the other.

8. In nature,the food relationship cannot be explained by a single food chain.Each organism is a member of more than one food chain.Several food chains are inter linked with one another forming a food web.

9. Food Web

10. Bibliography: Class IX Sub:Biology AP & Encarta. Presented by Mrs.Urmila Devi