Ecosystem: Introduction, Types, Structure and Functions
Posted on : 07-06-2018 Posted by : Admin

Ecosystem: Definition

As already discussed in the previous article, Ecosystem is the structural and functional unit of ecology where living organisms interact with each other and also with the surrounding physical environment. In other words, it is the whole community in which plants and animals live together. For example, Tropical rain forest with its trees, animals etc. make up the ecosystem. In the year 1935, AG Tansley coined the term ecosystem. According to Tansley, ecosystem consists of organisms and inorganic components in a relatively stable equilibrium. As per E P Odum, ecosystem is the basic functional unit of organisms and their environment interacting with each other.

In an ecosystem, biotic and abiotic components are inseparably inter-related. These components interact with each other. As ecosystem is an open system, the energy and the components can easily flow throughout the boundaries. 


Types of Ecosystem

Mainly there are two types of ecosystems. Namely terrestrial ecosystem and aquatic ecosystem

1. Terrestrial ecosystem: This is the ecosystem which exists on land. It can be further divided into the following types,

  • Forest ecosystem
  • Grassland ecosystem
  • Desert ecosystem

2. Aquatic ecosystem: This is the ecosystem which exists in water. It can be further divided into,

  • Fresh water ecosystem (Pong or lake or river ecosystem)
  • Marine ecosystem (Ocean ecosystem)


Structure of Ecosystem

Abiotic components: It is the nonliving component of the ecosystem. The abiotic components of the ecosystem include basic inorganic elements and compounds like soil, water, oxygen and a variety of organic compounds. Also some physical factors like humidity, wind and water currents, solar energy etc. are also abiotic components.

Biotic components: It is the living component of the ecosystem. In terms of nutrition, biotic components can be grouped as autotrophs and heterotrophs. Autotrophs include green plants which make their own food with the help of sunlight and other inorganic matter. Heterotrophs include non-green plants and all animals which depend on autotrophs for their food needs.

On a broader scale biotic components includes producers, consumers and decomposers

Producers- Producers are the autotrophic elements of the ecosystem. They use radiant energy of the sun during the process of photosynthesis whereby carbon dioxide is assimilated and the light energy is converted into chemical energy.

Consumers- These are the members of the ecosystem which consume the food prepared by the producers and hence are called as consumers. The following are different classes included in consumers,

Primary consumers: These are herbivorous animals which are dependent on the green plants for their food. For example, insects, cow, deer, buffalo, goat etc.

Secondary consumers: These are carnivorous and omnivorous animals which feed on primary consumers and producers or both. For example, sparrows, fox, crow, snake etc.

Tertiary consumers: These are the top carnivorous animals which feed on other carnivorous, herbivorous and omnivorous animals. For example, lion, tiger, vulture, hawks etc.

Scavengers and parasites: These are the parasitic plants and animals which make use of the living tissues of different plants and animals. The scavengers use dead remains of animals and plants as their feed.

Decomposers and transformers- These are living components of the ecosystem. Decomposers and transformers help to maintain the dynamic structure of ecosystems. The decomposers attack dead remains of producers and consumers. Decomposers degrade the complex organic substances into simpler compounds.  Whereas the transformers change the organic compounds into inorganic forms that are suitable for reuse by the producers or green plants. For example, Fungi and Bacteria.

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