Introduction to Ecosystem

Concept of ecosystem

The term ecosystem was first coined by A.G Tansley in 1935 and it was derived from two greek words 'eco' and the' system' where eco means environment and system mean interaction or interdependent. According to A.G. Tansley ecosystem is the system resulting from the integration of abiotic and biotic components of an environment.

Organization of ecosystem

The ecosystem is organized by two aspects. They are:

• Structural aspect
• Functional aspect

Structural aspect

The structure of the ecosystem is composed of two main component i.e. biotic and abiotic which are interacting together. Abiotic components include inorganic compounds like gases, water, minerals etc. The biotic factors include all the living organism living in an environment. Eg; producers, consumers, decomposers.

Functional aspect

The functional aspect of the ecosystem is composed of flow of energy and cycling of nutritious which makes the ecosystem stable and continues lifecycle.

Type of ecosystem

There are mainly two types of ecosystem. They are:

• Aquatic ecosystem
• Terrestrial ecosystem

Aquatic ecosystem

The ecosystem which operates in the aquatic medium is called the aquatic ecosystem.

Terrestrial ecosystem

The ecosystem which operates in the terrestrial medium is called the terrestrial ecosystem.

Biomass

The ecosystem of distinct terrestrial areas with climax plants and associated animals are known as biomass. In a biome, the vegetation is of similar type, which depends on physical factors like nature of soil, amount of rainfall, light, topography and geographical barriers, etc.

Different types of biomass are as follows:

Longitudinal biomass:Major terrestrial longitudinal biomass is Tundra, Coniferous, Deciduous forest, Tropical rain forest, Tropical Savanah, Grassland, and Desert.

Altitudinal biomass:as climate varies with altitude, their temperature and rainfall determine the type of altitudinal biome. In the tropical mountains, the sequence of four types of biomes from the base of the mountain to the snow line are Tropical or terai forest, Deciduous forest, Coniferous forest and Tundra.

Ecological Niche or Niche

For a species to maintain its population, its individuals must survive and reproduce. Certain combinations of environmental conditions are necessary for individuals of each species to tolerate the physical environment, obtain energy and nutrients, and avoid predators. The total requirements of a species for all resources and physical conditions determine where it can live and how abundant it can be at any one place within its range. These requirements are considered as the ecological niche.
Tadpole larvae of frog and adult of frog occupy different ecological niches as the former is herbivorous and aquatic whereas the latter is carnivorous and amphibian. A species' niche includes all of its interactions with the biotic and abiotic factors of its environment. It is advantageous for a species to occupy a unique niche in an ecosystem because it reduces the amount of competition for resources that species will encounter.

Types of Ecological Niche

Ecotypes: It refers to the species having a wide range of distribution evolve genetically, adapted local populations which differ on the basis of morphological and physiological characters. Ecotypes are found in plants and sessile animals.

Ecotone: It is defined as the zone where two or more different communities meet and integrate. It contains few species from both communities. For example; zone between field and a forest.