Definition – A structural and functional unit of biosphere consisting of community of living beings and physical environment, both interacting and exchanging materials between them.

Ecosystem includes plants, trees, animals, fish, birds, micro-organisms, water, soil, and people.

Components of ecosystem

Abiotic components

These are inorganic and nonliving parts of the world. The abiotic components consist of soil, water, air, and light energy etc. It also include a large number of molecules of oxygen, nitrogen etc. and physical processes including earthquakes, volcanoes, forest fires, floods, climates, and weather conditions.

1. Energy

Sun is the main source of energy. In the case of plants, the sun is the direct source of supply of energy. Animals indirectly utilize this energy when they eat plants or animals or both.


2. Rainfall

Water is a basic need for every living being for survival. Water helps to regulate body temperature. Further, water bodies form the habitat for many aquatic plants and animals.


3. Temperature

It is a very important factor which greatly affect the survival of organisms. Organism can tolerate only a certain range of temperature and humidity.


4. Atmosphere

The earth’s atmosphere is responsible for creating conditions suitable for the existence of a healthy biosphere on this planet. It is made up of 21% oxygen, 78% nitrogen and 0.038% carbon dioxide, and other inert gases (0.93% Argon, Neon etc).


5. Substratum

Land is covered by soil and wide variety of microbes, protozoa, fungi, and small animals thrive in it. Roots of plants pierce through the soil to tap water and nutrients. Organisms can be terrestrial or aquatic. Terrestrial animals live on land. Aquatic plants animals and microbes live in freshwater as well as in the sea. Some microbes live even in hot water vents under the sea. Some microbes live even in hot water vents under the sea.


6. Materials

Organic compounds such as proteins, carbohydrates, lipids, humic substances are formed from inorganic compound on decomposition.

Inorganic compound such as carbon carbon dioxide, water, sulphur, nitrates, phosphates, and ions of various metals are essential for organisms to survive.

7. Latitude and Altitude

Latitude has a strong influence on an area’s temperature, resulting in change of climates such as polar, tropical, and temperate. These climates determine different natural biomes.

Latitude and Altitude

Biotic Components

These include living organisms comprising plants, animals and microbes and are classified according to their functional attributes into producers and consumers.

a) Primary Producers – Autotrophs (self-nourishing)

Primary products are basically green plants (and certain bacteria and algae).

Primary products – green plants

They synthesize carbohydrate from simple inorganic raw material like carbon dioxide and water on the presence of sunlight by the process of photosynthesis for themselves, and supply indirectly to other non-producers.
In terrestrial ecosystem, producers are basically herbaceous and woody plants, while in aquatic ecosystem producers are various species of microscopic algae.

b) Consumers – Heterotrophs or phagotrophs (other nourishing)

Consumers are incapable of producing their own food (photosynthesis)
They depend on organic food derived from plants, animals or both.
Consumers can be divided into two broad groups namely micro and macro consumers.

Macro Consumers

They feed on plants or animals or both and are categorised on the basis of their food sources.

Herbivores are primary consumers which feed mainly on plants e.g. cow, goat.
Secondary Consumers feed on primary consumers. E.g. Jackal.
Carnivores which feed on secondary consumers are called tertiary consumers. E.g . Tiger
Omnivores are organisms which consume both plants and animals. E.g. man, monkey.

Micro Consumers – Saprotrophs (decomposers or osmotrophs)

They are bacteria and fungi which obtain energy and nutrients by decomposing dead organic substances (detritus) of plant and animal origin.
The products of decomposition such as inorganic nutrients which are released in the ecosystem are reused by producers and thus recycled.
Earthworm and certain soil organisms are detritus feeders and help in the decomposition of organic matter and are called detritivores.

Classification of Ecosystem

Classification of Ecosystem

What ecosystem gives us?

  • Ecosystem provides provision of food, fuel and fibre.
  • Provision of shelter and building materials.
  • Purification of air and water.
  • Detoxification and decomposition of wastes.
  • Stabilization and moderation of the Earth’s climate.
  • Moderation of floods, droughts, temperature extremes and the forces of wind.
  • Generation and renewal of soil fertility including nutrient cycling.
  • Pollination of plants.
  • Maintenance of genetic resources
  • Cultural and aesthetic benefits.
What ecosystem gives us?