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Chapter 4 major domains of

the earth

Our Earth is a unique planet of the Solar system. The Earth
is the only planet where life exists. All life sustaining
elements land, water and air are found on the earth. We
call them Lithosphere—the solid portion of the earth, the
Hydrosphere-water in all its forms and the Atmosphere-
the gaseous layer that surrounds the earth. We find land,
water and air together in the Biosphere which contains all
forms of life. Let us discuss them one by one.
1. lithoSPhere The Four domains of the earth

The upper surface of the earth which is made of soil and rocks, is called the lithosphere.
Its top layer is known as crust. This crust is thick under continents and thin under oceans.
Land covers about 29% of the earth’s surface.

The lithosphere includes all types of land masses. The large land masses are called
continents while the large water bodies that surround the continents are called oceans.
There are seven continents—
i. aSia

It is the largest continent and most of it lies in the northen and eastern hemispheres. It
extends from 80° North to 10° South latitudes and from 28° East to 170° West longitudes.
The Tropic of Cancer passes through this continent. It is joined to the land mass of Europe
and thus we use the term Eurasia for this combined land mass. The mountain ranges of the
Urals, the Black sea and the Caspian sea separate the two continents. It lies to the west of
Asia, but not separated from Asia by any water body.

S.No. Continents Area (Million sq km) % of the Earth’s total land area

1. Asia 44.36 29.6
2. Africa 30.32 20.2

3. North America 24.25 16.2
4. South America 17.80 11.8

5. Antarctica 14.24 9.5
6. Europe 10.50 7.0

7. Australia 8.51 5.7

• Asia and Europe are combindely known as Eurasia.
• No aquatic animal can live in the Dead Sea because it has about 25.5 percent salt and also
nobody can sink in it due to its density.

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