Major Domains Of the Earth

Major Domains Of the Earth

by GIRIJA JOSHI & SHREYA UNDIRWADKAR

​Introduction

As you have read in the first chapter, the earth is the only planet which has life. Human beings can live here because the life sustaining elements of land, water and air are present on the earth.The surface of the earth is a complex zone in which three main components of the environment meet, overlap and interact. The solid portion of the earth on which we live is called the Lithosphere. The gaseous layers that surround the earth, is the Atmosphere, where oxygen, nitrogen, carbondioxide and other gases are found. Water covers a very big area of the earth’s surface and this area is called the Hydrosphere. The Hydrosphere comprises water in all its forms, that is, ice, water and water vapour​

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.

​Lithosphere

​Atmosphere

​The earth is surrounded by a layer of gas called the atmosphere. This thin blanket of air is an integral and important aspect of the planet. It provides us with the air we breathe and protects us from the harmful effects of sun’s rays.

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. These layers starting from earth’s surface are called the troposphere, the stratosphere, the mesosphere, the thermosphere and the exosphere.

​Atmosphere

The atmosphere contains components like oxygen, Carbon - Dioxide ,Nitrogen, Arogen , Methane and other gasses

​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. As running water in oceans and rivers and in lakes, ice in glaciers, underground water and the water vapour in atmosphere, all comprise the hydrosphere.​

​Hydrosphere

​Out of that 97% is salty water which is found in seas and oceans and 3% is potable water which is found in rivers , lakes ,ponds etc..

​Biosphere

The biosphere is the narrow zone of contact between the land, water and air. It is in this zone that life, that is unique to this planet, exists.​

​Continents

​There are 7 major continents.These continents are – Asia,

Europe, Africa, North America, South America,Australia and Antarctica

The large landmasses are known as the continents

​Asia

Asia is the largest continent. It covers about onethird of the total land area of the earth. The continent lies in the Eastern Hemisphere. The Tropic of Cancer passes through this continent. Asia is separated from Europe by the Ural mountains on the west​

​Europe

​Europe is much smaller than Asia. The continent lies to the west of Asia. The Arctic Circle passes through it. It is bound by water bodies on three sides.

​Africa

​Africa is the second largest continent after Asia. The Equator or '0' latitude runs almost through the middle of the continent. A large part of Africa lies in the Northern Hemisphere. Look at the Figure 5.1; you will find that it is the only continent through which the Tropic of Cancer, the Equator and the Tropic of Capricorn pass.

​North America

​North America is the third largest continent of the world. It is linked to South America by a very narrow strip of land called the Isthmus of Panama. The continent lies completely in the Northern and Western Hemisphere. Three oceans surround this continent

​South America

South America lies mostly in the Southern Hemisphere. Which two oceans surround it on the east and the west? The Andes, world’s longest mountain range, runs through its length from north to south . South America has the world’s largest river, the Amazon​

​Australia

Australia is the smallest continent that lies entirely in the Southern Hemisphere. It is surrounded on all sides by the oceans and seas. It is called an island continent.​

​Antartica

Antarctica, completely in the Southern Hemisphere, is a huge continent. The South Pole lies almost at the centre of this continent. As it is located in the South Polar Region, it is permanently covered with thick ice sheets. There are no permanent human settlements. Many countries have research stations in Antarctica. India also has research stations there. These are named as Maitri and Dakshin Gangotri​

​Oceans

Oceans are the major part of hydrosphere. They are all interconnected. The ocean waters are always moving. The three chief movements of ocean waters are the waves, the tides and the ocean currents. The five major oceans are the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Southern Ocean and the Arctic Ocean, in order of their size

​Pacific Ocean

​The Pacific Ocean is the largest ocean. It is spread over one-third of the earth. Mariana Trench, the deepest part of the earth, lies in the Pacific Ocean. The Pacific Ocean is almost circular in shape. Asia, Australia North and South Americas surround it.

​Antartic Ocean

​The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the World Ocean, generally taken to be south of 60° S latitude and encircling Antarctica.

​Indian Ocean

The Indian Ocean 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. The Southern Ocean encircles the continent of Antarctica and extends northward to 60 degrees south latitude.​

​Artic Ocean

​The Arctic Ocean is located within the Arctic Circle and surrounds the North Pole. It is connected with the Pacific Ocean by a narrow stretch of shallow water known as Berring strait. It is bound by northern coasts of North America and Eurasia.

Multiple Choice

Which are the mountain ranges which separate Europe from India?

• The Andes

• Everest

• The Ural mountains

• The Himalyas

• None of the above

Multiple Select

Indian research stations in Antarctica

• Maitri

• Dashin Isthamus

• Strait

• Dakshin Gangotri

Multiple Choice

The continent with surrounded with 3 oceans is

• Asia

• Australia

• North America

• Africa

• South America

Multiple Choice

Which is the smallest continent ?

• Asia

• Europe

• Australia

• Antarctica

• Africa

Multiple Choice

The domain of the earth consisting water is

• Atmosphere

• Biosphrere

• Hydrosphere

• Lithosphere

Multiple Choice

Which is the smallest ocean?

• Atlantic Ocean

• Indian Ocean

• Artic Ocean

• Pacific Ocean

• Southern Ocean