Biotic component means the living components of an ecosystem. On the basis of food relations, they can be put in the following categories-
(a) Producers
(b) Consumers,
(a) Producers: They are the living members of an ecosystem which synthesise their own food. Green plants are called producers because they are able to synthesise their food in the presence of sunlight and chlorophyll by taking carbon dioxide from the atmosphere and water from the soil. They are also called as autotrophs as they synthesise their own food. As green plants can convert solar energy into chemical energy of food, so they can also be called converter.
(b) Consumers or Heterotrophs:
Consumers or heterotrophs are those animals which eat foodstuffs manufactured by green plants. They cannot manufacture their own food. Phagotrophs are such heterotrophic organisms which digest their food within their body.
Consumers are of three types:
1. Primary Consumers: All the herbivores which feed on producers (green plants) are called primary consumers. Some common examples of primary consumers are insects, goat, cow, rabbit, grasshopper, deer, parrot etc.
2. Secondary Consumers: Carnivores eat the herbivores or primary consumers and are called secondary consumers. Some common examples of secondary consumers are a snake, frog, fox, lizard, etc. They are also called primary carnivores.
3. Tertiary Consumers: They are also called secondary carnivores. Big carnivores eat the secondary consumers and are called as tertiary consumers. Lion and tiger are common examples of tertiary consumers.
4. Omnivore: An animal which eats plants, as well as flesh of other animals, is called omnivore. Man is an example of an omnivore.
(c) Decomposers or Micro consumers or osmotrophs or saprotrophs: These are the micro-organisms which feed on dead bodies of plants and animals and break down complex organic substances into simpler inorganic substances. Putrefying bacteria and fungi decompose the dead plants and animal bodies into ammonia and other simpler substances. Through the decomposers, the elements enter the earth again, which are again taken up by plants. Thus, the cycle of matter continues.
