Revision Notes of Ch 9 The Living Organisms and their Surrounding Class 6th Science

Topics in the chapter

  • Habitat 
  • Adaptations
  • Types of habitat 
  • Acclimatisation
  • Components of a habitat

What is Habitat?

→ The surrounding where an organism lives, where it can find food, shelter and a favourable condition for breeding is known as its habitat.


→ The ability of living organisms to adjust themselves to the surroundings is called as adaptation.

→ Adaptations are the changes in structure or behaviour of an organism that will allow the organism to survive in that habitat.

Types of habitat

→ There are two types of habitat:
(i) Terrestrial habitat
ii. Aquatic habitat

Terrestrial habitat

→ It refers to the land where all plants and animals survive.

→ Animals and plants which live on land are called as terrestrial animals and terrestrial plants.

→ Terrestrial habitat is further classified into:
(i) Forests
(ii) Grasslands
(iii) Deserts
(iv) Mountains
(v) Polar Regions

(i) Forest

→ These are large areas covered with trees and plants.

→ Organisms living in the forest depend upon abiotic factors like air, availability of water, temperature, sunlight etc.

→ Three types of forests are tropical forests, temperate forests and boreal forests.

(ii) Grasslands

→ These are mainly covered by long and thick grasses.

→ Temperature ranges between -20℃ and 30℃.

→ Annual rainfall they receive varies between 50cm and 90cm.

(iii) Deserts

→ These are the areas that receive scanty rainfall.

→ These are dry with sand covering the whole region.

→ Deserts are mostly hot regions but some of them are even too cold regions.

(iv) Mountains

→ These regions are rocky and dry.

→ Sometimes water occurs as flowing streams.

→ Plants present on hills are xerophytes. These are conical and evergreen.

(v) Polar region

→ These regions are covered with high snowy peaks.

→ Animals found here are adapted by having thick furry coat on the skin.

Aquatic habitat

→ It refers to the region covered with water where plants and animals survive.

(a) Freshwater habitat: These are the water bodies filled with fresh water. These include rivers, lakes, ponds, streams etc.

(b) Marine habitat: Ocean and seas are termed to be marine habitat. These are full with life. Different varieties of organisms exist in marine habitat.

(c) Coastal habitat: This is the region represented by the place where land meets the sea.


→ The ability of an organism to make small adjustments or changes in the body in a short period of time to adjust itself to the surrounding atmosphere is called acclimatisation.

→ There are two types of components of a habitat:
(i) Biotic components
(ii) Abiotic components

Biotic components 

→ It include all the livings organisms in a habitat, i.e. plants, animals and microorganisms.

Abiotic components 

→ It includes all the non-living things in a habitat, i.e. air, soil, water, sunlight and temperature.

→ The favourable conditions for survival of living organisms are provided by abiotic components.

Abiotic components

(i) Air

→ Air is essential for all the living organisms on earth.

→ Plants and animals take in oxygen from the air during respiration.

→ Air is required by organisms to cool their body.

(ii) Soil

→ Soil is the topmost layer of the earth.

→ Soil is rich in minerals and microorganisms which help in different ways for plant growth.

(iii) Water

→ Water forms a medium for many metabolic reactions taking place inside the body.

(iv) Sunlight

→ Sun is the ultimate source of energy for all the living organisms on earth.

→ Plants depend on sunlight for synthesising their food by the process of photosynthesis.

(v) Temperature

→ Temperature at a place depends on the sunlight available at the particular place.

→ Temperature also influences the humidity of that particular place.
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