(A) Biotic Components

Biotic components refer to the living world of an ecosystem. Different components are connected through food and various other relations. Food is a source of energy to the body to perform functions and is essential for the growth and body building.
Initially in all cases the pathway of food in every ecosystem is

Producers are also called transducers as they are able to change radiant energy to chemical form. All the other organisms (heterotrophs) depend upon producers for their survival. Besides this producers also maintain CO2/O2 balance of nature.

2. Consumers.
The animals which consumes energy produced by producers as food are called consumers. They are also called phagotrophs. Consumers are differentiated into two categories - herbivores and carnivores.

3. Decomposers.
The non-green organisms like fungi and bacteria which are incapable of producing their own food living on dead and decaying plants or animal parts and are consumers of a special kind are called decomposers. They secrete digestive enzymes externally and absorb liquid food. They are called reducers and add raw materials and minerals back into the substratum.
Detrivores or Scavengers. Animals which feed on dead bodies of other organisms e.g. termites, carrion buttes. They are helpful in quick disposal of the dead bodies.