Basic components of eco-system are as follows:
1. Biotic components.
2. Abiotic components.
Biotic Components :
The biotic components are all the living organisms present in an environment. In an eco-system, the connections between species are generally related to food and their role in the food chain.
Thus, on the basis of nutritional relationship (food preparation and food dependency), biotic components can be sub-divided into two sub-components: (i) Autotrophic components (ii) Heterotrophic components (i) Autotrophic Components (auto means 'self, tropic means 'nourishing')
The autotrophic components include green plants, photosynthetic bacteria, chemosynthetic microbes, etc.
The autotrophic components are known as producers. The main function of these is to absorb energy from non-living organisms and make it available to all living organisms.
The main producers are, of course green plants. These plants possess a green pigment called 'chlorophyll', which transducers solar energy.
Such producers absorb solar energy through the light trapping pigments, chlorophylls and convert it to chemical energy with the help of inorganic substances such as water and carbon dioxide, as well as organic substances such as enzymes.
The oxygen thus evolved, is used for respiration by the living organisms.
The other type of autotrophy called 'chemo-autotrophy', use the energy generated in an oxidation-reduction process. The microorganisms like beggiatoa and sulphur bacteria are some examples of chemo-autotrophy.
However, the importance of chemo-autotrophy as producers is minimal in an eco-system. (ii) Heterotrophic components (Hetero means 'different', tropic means 'nourishing')
Heterotrophic components are the living organisms that are unable to prepare their own food like autotrophy, but consume or decompose the complex food material prepared by the autotrophy or producers. Heterotrophy, are thus of two types:
(b) Decomposers and transformers
Consumers are the living organisms that consume food prepared by producers. On the basis of dependency on food habits, consumers can be of four types:
(i) Primary consumers (ii) Secondary consumers (iii) Tertiary consumers (iv) Decomposes and transformers.
(i) Primary consumers:
Those that feed directly on green plants and are purely herbivorous animals, e.g., cow, dove, buffalo, deer, elephants, and insects like butterfly.
(ii) Secondary consumers:
Those that feed on primary consumers and can be purely carnivorous (flesh eating) as well as omnivorous (plants and flesh eating), e.g., small birds, toad, lizard, small fish.
(iii) Tertiary consumers:
Those that feed on secondary consumers and are the top carnivores. They can feed on primary consumers also. Thus, the tertiary consumers feed on other carnivores, omnivorous as well as herbivorous animals, e.g., lion, tiger, hawk, vulture, snake, peacock, large fish, etc.
(b) Decomposers and Transformers:
Decomposers are also heterotrophic organisms but they depend upon dead organisms for their food. They are chiefly microorganisms like bacteria, fungi, etc.
Some invertebrate animals like protozoa (amoeba, endameba, euglena), as well as earthworms, decompose dead organisms to derive food from them and can therefore, be classified as decomposers.
The decomposers attack the dead bodies of producers and consumers, degrading the complex organic substances like cellulose, semi-cellulose, proteins and fats into simple substances.
The transformers then convert these simple organic substances into the inorganic form, suitable for reuse by the producers. The decomposers and transformers are very important microorganisms which maintain the dynamic equilibrium in the eco-system.
Abiotic Components :
All non-living parts of the eco-system are abiotic components. These non-living substances enter the body of the living organisms, participate in various metabolic activities and finally return to the environment after their death. Abiotic components can be classified into three main groups:
(a) Physical components:
These are the various environmental factors like temperature, light, air, humidity, wind, etc.
(b) Inorganic components:
The various inorganic substances such as water, carbon, nitrogen, sulphur, phosphorus, calcium, potassium, sodium, oxygen, etc., are involved in the cycling of materials in the eco-system.
(c) Organic components:
The various organic substances like carbohydrates, proteins and lipids largely form the living body and link abiotic and biotic components.