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Chapter 24- Ecosystem


Ecosystem is defined as the natural functional egological unit which is comprising of living organisms interect among themselves and also with the surroundings physical environment.
There are two basic catagories of ecosystem, namely Terrestrail and aquatic ecosystem.

Terrestrial ecosystem: The ecosystem which is found only on landform is known as Terrestrial ecosystem. Forest, grasslend, desert etc are terrestrial ecosystem.

Aquatic Ecosystem: The ecosystem which is found only in a body of water is known as Aquatic ecosystem. Ponds, lake, river etc etc are aquatic ecosystem.

The ecosystem is formed of two components, namely biotic like producer, consumer, decomposers and abotic factors like soil, water, heat, light, etc.

Biotic Factors: It is defined as any living components that shapes its environment.It includes all the living organisms . r. Biotic factors refer to ecosystem which include producers, consumers and decomposers. Biotic factors are classified as follows:

  1. Producer: They are the living beings who can prepare their own food. Plants with green pigments are producers. They are also known as autotrophs.

  2. Consumer: Consumer are the living beings which depend on producers for food. On the basis of food they obtain, they are classified into following groups.
    Primary consumers, Secondary consumers and tertiary consumers.

    Primary consumers are herbivores and they depend directly on plants for food. Example of primary consumers are cow, buffalo, goat, rabbit, squirrel etc.

    Secondary consumers directly depends upon primary consumer for food . They are carnivores Example: cat, fox, frog etc.

    Tertiary Consumers depends upon primary and secondary consumers for food. These living beings are physically developed and strong. Examples are whale, crocodile etc. Animals like primary and secondary consumers are carnivores or omnivores.

  3. Decomposers: Microorganisms like bacteria and fungi present in soil help to decompose dead bodies and convert into small particles. Such small particles are absorbed by root of plants. Plants obtain essential particles from soil. Decomposers help in maintaining balanced ecosystem.
The examples make you understand deeply about this factors:

i) Forest ecosystem
Producer = tree,grass
Primary Consumer = Deer,buffalo
Secondary Consumer = Fox
Tertiary Consumer = Tiger

ii) Pond ecosystem
Producer = algae
Primary Consumer = small fishes, larva of mosquito
Secondary Consumer = Frog, Big fishes
Tertiary Consumer = snake

Abiotic Factors: It is defined as the non-living substances and physical parts of the environment, that helps for the circulation of the ecosystem properly. It balances the ecosystem.

They do play an important role in supporting life, or biotic factors all around the world. It includes the physical conditions of environment which is responsible for growth, maintenance, and reproduction of organisms. Those components are:
  1. Atmosphere
  2. Water
  3. Soil
  4. Solar Energy
  5. Temperature
Why these factors affect ecosystem? Explain.

Relationship Between Producer Consumer and Decomposer

The producer, consumer and decomposers are closely related with each others.Producers make their own food. They do not have to obtain energy from other organisms. They obtain their energy from the sun and make food with that energy through the process of photosynthesis.Producers are eaten (consumed) by consumers(the herbivores or primary consumers), when either of them die , they are consumed by decomposers(converted into simpler form).Likewise, when they are mixed into the soil they are absorved by the green plants for grownth and reproduction. And the phenomena occours continously.

For example: Sun → Grass → Cow → Lion → Fungi → Soil → Grass .....so on
Try out with more examples. Explain.


Every organism needs to obtain energy in order to live. For example, plants get energy from the sun, some animals eat plants, and some animals eat other animals.

For an ecosystem to work there has to be a flow of energy within it. The organisms of the ecosystem need energy in the form of food. The ultimate source of this energy is the sun. Producers like green plants trap solar energy and convert it into the chemical energy of food. When a primary consumer eats the producer, a part of this energy is passed on to it.
A food chain in an ecosystem is a process of transfer of food energy from producer to primary consumer, secondary consumer is called as food chain.

Examples: Grass → Deer , Musk → Tiger


Interrelation between food is known as food chain. Living organisms obtain their nutritious factors from food chain. The inter linkage of many food chain forms an integrated network. This is called as food web.

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