Components of the Ecosystems: Biotic Components and Abiotic Components!
1. Biotic Components:
In an ecosystem organisms are usually divided into two categories on the basis of their nutritional (trophic) relationship.
(a) Autotrophic component, and
(b) Heterotrophic components.
(a) Autotrophs are those organisms which can produce their own food. These are green plants (with chlorophyll) and certain bacteria, which obtain their energy from the sun and through photosynthesis, produce food. Since these organisms produce food for all the other organisms, they are known as producers.
(b) Heterotrophs are those organisms which depend directly or indirectly upon the autotrophs for their food, thus known as consumers.
The consumers are of two types:
(i) Macro consumers, also known as herbivores, carnivores or omnivores. Herbivores are the plant eaters, while carnivores are animal eaters. On the other hand, omnivores eat all kinds of food. They all are phagotrophs which include chiefly animals that ingest other organic and particulate organic matter. These are also known as primary consumers.
(ii) Micro consumers, also known as decomposers or osmotrophs. They are decomposers because of their role in decomposition of dead organic matter. They secrete digestive enzymes to break down food into simpler substances and then absorb the digested food.
Functionally, the biotic components can be divided into three types, viz., producers, consumers and decomposers. Producers produce their own food like plants, which are primary producers, while man and animals obtain food from plants. Similarly, consumers are also primary, secondary or tertiary.
Man, cow, goat, etc., are primary consumers, while meat eaters are secondary consumers. Tertiary consumers are those animals which eat meat such as snakes (who eat frogs), peacocks (who eat snakes), etc. Among decomposers those bacteria, fungi, etc., have been included which are responsible for decomposition of a product and release inorganic nutrients in environment.
2. Abiotic Components:
The physical environment with its several interacting variables constitutes the abiotic component of ecosystem. It consists of (i) the lithosphere, i.e., the solid mineral matter of the earth, (ii) the water in the oceans, rivers, lakes, etc., or in other words, the hydrosphere, (iii) the gaseous mixture in the air (the atmosphere), and (iv) the radiant solar energy.
Figure 2.1 is a generalised depiction of the structural elements of an ecosystem and their functional linkages.