Domains of The Earth-Geography Notes For W.B.C.S Examination.

পৃথিবীর ডোমেনস -WBCS পরীক্ষার জন্য ভূগোলের নোট।

Why always elevation or height of the land, mountain is measured from Sea Level ?

All the oceans of the earth are connected with each other because of these the level of sea water is same everywhere and Sea level is taken as zero that’s the reason for measuring the height of mountain, land from sea level.Continue Reading Domains of The Earth-Geography Notes For W.B.C.S Examination.

The earth’s surface is a complex zone in which the three major components of the environment meet, overlap and interact.

The four domains of the earth

• Lithosphere: The solid portion of the earth
• Atmosphere: The gaseous layers that surround the earth
• Hydrosphere: Water covers a very big area of the earth’s surface and this area is called the Hydrosphere
• Biosphere: It is the narrow zone where land, water and air together are found.

Lithosphere

• The solid portion of the earth is called the Lithosphere.
• It comprises the rocks of the earth’s crust and the thin layers of soil that contain nutrient elements which sustain organisms.

There are two main divisions of the earth’s surface

1. Continents- the large landmasses.
2. Ocean basins- the huge water bodies.

Hydrosphere

• The earth is called the blue planet.
• More than 71 per cent of the earth is covered with water and 29 per cent is with land. Hydrosphere consists of water in all its forms.
• More than 97% of the Earth’s water is found in the oceans and is too salty for human use.
• Hydrosphere consists of water in all its forms like running water in oceans and rivers and in lakes, ice in glaciers, underground water and the water vapour in atmosphere.
•  97% of the Earth’s water is found in the oceans and is too salty, the rest of the water is in the form of icesheets and glaciers or under the ground and a very
  small percentage is available as fresh water for human use

Oceans

• The three chief movements of ocean waters are the waves, the tides and the ocean currents.
• Oceans are the major part of hydrosphere and they are all interconnected.
• The five major oceans in order of their size are
  1. the Pacific Ocean:  It is almost circular in shape. Asia, Australia, North and South Americas surround it.
  2. the Atlantic Ocean: It is the second largest Ocean in the world. It is ‘S’ shaped. It is flanked by the North and South Americas on the western side, and Europe and Africa on the eastern side.
  3. the Indian Ocean: It is the only ocean named after a country, that is, India. The shape of ocean is almost triangular. In the north, it is bound by Asia, in the west by Africa and in the east by Australia.
  4. the Southern Ocean: It surrounds the continent of Antarctica
  5. the Arctic Ocean:  It is located within the Arctic Circle and surrounds the North Pole. The Berring strait a narrow stretch of shallow water connects it with the Pacific Ocean.

Atmosphere

The earth is surrounded by a layer of gas called the atmosphere.

• The atmosphere extends up to a height of about 1,600 kilometres.
• The atmosphere is divided into five layers based on composition, temperature and other properties and they are:
  1. the troposphere
  2. the stratosphere
  3. the mesosphere
  4. the thermosphere
  5. the exosphere
• A bout 99 per cent of clean and dry air in the atmosphere is composed mainly of nitrogen and oxygen. Nitrogen 78 per cent, oxygen 21 per cent and other gases like carbondioxide, argon and others comprise 1 per cent by volume.

Biosphere – The Domain of Life 

• The biosphere is the narrow zone of contact between the land, water and air.
• It is the zone where life exists that makes this planet unique.
• The organisms in the biosphere are commonly divided into:
  1. the plant kingdom
  2. the animal kingdom
• The three domains of the earth interact with each other and affect each other in some way or the other.

Our own publications are available at our webstore (click here).

For Guidance of WBCS (Exe.) Etc. Preliminary , Main Exam and Interview, Study Mat, Mock Test, Guided by WBCS Gr A Officers , Online and Classroom, Call 9674493673, or mail us at – mailus@wbcsmadeeasy.in
Visit our you tube channel WBCSMadeEasy™ You tube Channel
Please subscribe here to get all future updates on this post/page/category/website