Ecosystem Class 12 Notes

What is an Ecosystem?

An ecosystem consists of all the living organisms including plants, insects, microorganisms, birds and animals and non-living things including rocks, soil, water and sunlight in the community interacting with each other in a given area of their environment. It is a functional unit of nature and includes both abiotic and biotic components.

Biotic and Abiotic Components of Ecosystem

Biotic Components are the living components involved in shaping the ecosystem. It includes biotic factors such as:

  • Producers: All green plant in the ecosystem are termed as the producers, as they produce their own food by making use of solar energy. All living organisms are dependent on plants for both oxygen and food.
  • Consumers: They include both primary consumers and secondary consumers. As animals depend on plants for their food, they are called as the consumers. Primary consumers feed directly of Producers for their food and the secondary consumers feed on the primary consumers for their food. All herbivores animals are an example of Primary consumers. Carnivores and apex predators make up the secondary and tertiary consumers.
  • Decomposers: They are the saprophytes which include fungi and bacteria. Decomposers convert the dead matter into nitrogen and carbon dioxide and the process is called decomposition.

Abiotic components include inorganic materials like air, water, and soil.

Types of Ecosystem

Freshwater, Terrestrial and Ocean Ecosystem are the three major classes of ecosystems. Other subcategories of ecosystem falls under one of these three major classes.

Factors affecting the Ecosystem

There are four important components of an ecosystem:

  • Productivity.
  • Decomposition.
  • Energy flow.
  • Nutrient cycling.

Few Important Questions

  • What is Nutrient cycling?
  • What is primary productivity?
  • Explain the components of an ecosystem?
  • Define ecological pyramids with examples?
  • List out the differences between Food chain and Food web?

Learn more about ecosystem from the topics given below:

Practise This Question

Identify the incorrect one of the following, related to Griffith’s transformation experiment.