The ecosystem is divided into two main components viz. Biotic (the living) and Abiotic (the non-living). The living component is usually comprised of producers, consumers and decomposer, while the non-living component to is divided to two types viz. materials and energy. Let us start the ecosystem structure with abiotic components.
Abiotic substances are the inorganic and organic substances present at any given time in an ecosystem. These are water, carbon dioxide, oxygen, nitrogen and other gases, minerals, salts and the entire range of elements and compounds outside the living organism.
These substances together constitute the ‘standing state’ of the ecosystem. These materials continually keep on cycling i.e., entering into the living system and then returning to the soil and atmosphere through death, decay and decomposition. It may be remembered here that different substances/elements are differentially available to the living systems. For example, elements like oxygen are quite readily available in free 02 or in C02 while the same element in the form of Si02 is in an inaccessible from.
The materials keep on cycling, termed as “biogeochemical cycles” or nutrient cycle. Energy is always necessary to run the cycles. The energy source is the solar radiation which the green plants trap and prepare food for themselves and the whole biotic component in the ecosystem.
Living organisms are highly organised. In order to survive and maintain, this internal order organisms need supplies of relevant nutrients. From the nutritional point of view, an ecosystem shall have three types of organisation viz. Producer, Consumer and Decomposer Organisms. Producers: These are the green plants which synthesize organic compounds and arc called autotrophic or self – productive.
They take inorganic compounds from the surrounding and manufacture organic moleclucs and living protoplasm from them. All green plants are photoautotrophs as they obtain their energy from light by the proccss called photosynthesis.
There are many photosynthetic bacteria having various ways of obtaining their carbon compound. Besides the photosynthetic organisms, there are chemosynthetic organisms also which are involved in the nitrogen cycle while some feeding on the hydrogen sulphide (H2S) released by hot vents obviously, all life depends upon the basic productive capacity of green plants and bacteria.
Consumers are animals which utilize the organic materials directly or indirectly manufactured by autotrophs.
They are called heterotrophs, which means different nutritional source. Primary consumers or herbivores directly consume the organic compounds of plants. Mamalian herbivores mostly are predators while most insect herbivores are parasites.
Secondary consumers are carnivores which feed on animals which generally are smaller than them. An omnivore is an organism that eats both plants and animals. Ilumans are omnivores par excellence.
These organisms break down the organic waste products and dead remains of organisms into the inorganic substances needed by the producers. Decomposers are often mocrorganisms. They play a vital role in nature.
Their nutrition is saprophytic that is, associated with rotten and decaying organic materials. In a sense, they are the digestive organisms of an ecosystem – converting complex chemicals to simple chemical forms. They provide the final essential link in the cycle of life.