What is an Ecosystem?

An ecosystem can be simply defined as a community of living beings in concurrence with nonliving components, which they will interact with each other. It can also be defined as the chain of interaction between organisms and its environment.

An ecosystem varies in its size. It can either be small as an oasis or vast as an ocean encompassing precisely limited spaces. They are usually controlled or influenced by both external and internal factors. External factors such as climate can be considered as a prime material that forms soil and topography that controls the entire configuration of the ecosystem.

Components and Structure of an Ecosystem

There are two main components of the ecosystem, namely: biotic and abiotic components.

  • Abiotic Components

They are the nonliving component of an ecosystem.  It includes air, water, soil, minerals, sunlight, temperature, nutrients, etc.

  • Biotic Components

They are the living components of an ecosystem. It includes biotic factors such as producers, consumers, and decomposers.

  • Producers include all autotrophs (plants), they produce their own food by utilizing the source of energy obtained from the sunlight. All living beings are dependent on plants for both oxygen and food.
  • Consumers include primary consumers and secondary consumers. Top carnivores and apex predators make up the tertiary consumers.
  • Decomposers include saprophytes (fungi and bacteria), that converts the dead matter into nitrogen and carbon dioxide. They are essential for recycling of nutrients to be used again by the producers.

Below figure demonstrates a simple food chain.

Food Chain

The sun is the ultimate source of energy on earth which provides energy for all plant life. This energy is utilized by the plants through the process of photosynthesis to synthesize their food. During this biological process, light energy is converted into chemical energy and is passed on through successive levels – from producers to consumers. The flow of energy from the producer to the apex predator is called the food chain.

The dead and decaying matter, along with organic debris is broken down into smaller bits by scavengers. These molecules are then absorbed by the reducers. After gaining the energy, the reducers liberate molecules to the environment in the form of chemicals that are utilized again by the producers.


Ecological Pyramids

An ecological pyramid is the graphical representation of the number, energy, and biomass of the successive trophic levels of an ecosystem. Charles Elton was a first ecologist to describe the ecological pyramid and its principals in the year 1927.

The biomass, number, and energy of organisms ranging from the producer level to the consumer level are represented in the form of a pyramid, which is known as the ecological pyramid.

Ecological Pyramids

The base of the ecological pyramid comprises of the producers, followed by the primary and secondary consumers. The tertiary consumers hold the apex. The producers generally outnumber the primary consumers, and similarly, the primary consumers outnumber the secondary consumers. And lastly, apex predators also follow the same trend as the other consumers, wherein, their numbers are considerably lower than the secondary consumers.

For example, Grasshoppers feed on crops such as cotton and wheat, which are plentiful. These grasshoppers are then preyed upon by common frogs, which are comparatively less in number. These frogs are then preyed upon by snakes such as cobras, in numbers they are even smaller than that of the frogs. Snakes are ultimately preyed on by apex predators such as the brown snake eagle.

In essence:

Cotton Grasshopper → Common Frog →  Cobra → Brown Snake Eagle

Types of an Ecosystem


There are different types of ecosystem and their size varies from each other, which can either be huge as an ocean or smaller by encompassing the precisely limited spaces. The three major classes of ecosystems, referred to as ‘biomes’, are as follows:

  • Freshwater Ecosystems

Pond and River Ecosystems are the two main freshwater ecosystems. These freshwater ecosystems are usually small and include different varieties of aquatic plants, aquatic animals, amphibians, insects, etc. Freshwater ecosystems are actually the smallest of the three major classes of ecosystems which comprises 1.8% of the total of the Earth’s surface.

  • Terrestrial Ecosystems

There are different varieties of Terrestrial ecosystems on Earth and some of the most common terrestrial ecosystems are as follows:

  1. Rainforests – They are extremely dense ecosystems, which includes different types of animals living in a very small area.
  2. Tundra – They usually have a moderately simple ecosystem, because of the very less living species found existing in these harsh conditions.
  3. Deserts – This ecosystem is quite the opposite of tundra, which includes more animals living in the extremely hot temperature.
  4. Savanna – This ecosystem is completely opposite of deserts, because of the amount of rain that they get every year. Savanna supports more life as it is a mixed wetland and grassland ecosystem
  5. Forests – There are different types of forests all over the world, which support a lot of plant and animal life and play an important role in the ecosystems.
  • Ocean Ecosystems

Ocean ecosystems, which is also called as the aquatic ecosystem or the marine ecosystems. It is the largest ecosystem of the Earth’s which include aquatic plants, animals and birds that hunt for fish and other insects on the ocean’s surface. The different kinds of ocean ecosystems are:

  1. Shallow water – Includes some tiny fish and coral living in shallow water close to the land.
  2. Deepwater – Includes big and gigantic creatures, which live deep in the oceans and right at the bottom of the sea.
  3. Warm water –Pacific Ocean is the best example for the warm water. It contains some of the most remarkable and complicated ecosystems in the world.
  4. Cold water – Includes Planktons, small fish, bigger fish and other creatures such as penguins or seals.

These entire ecosystems are controlled or influenced by both the internal and external factors.

This was a brief introduction to the Ecosystem. Stay tuned with BYJU’S to know more ecosystem, their types and components.

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Practise This Question

Which one of the following statements are correct for secondary succession?