QUESTION & ANSWERS OF MAJOR DOMAINS OF THE EARTH

CLASS: VI

SUBJECT: GEOGRAPHY

CHAPTER- 5

MAJOR DOMAINS OF THE EARTH

1. Define the following terms:

Continents, Ocean basins, Wind, Lithosphere and Hydrosphere. 

• Ans.- Continents- The large landmasses are known as the continents. 
• Ocean basin- Ocean basins are large basins that are below seas or oceans.
• Wind- Moving air is known as wind. 
• 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.
• Hydrosphere – 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.

2. Which strip of land (isthmus) connects North America with South America?

Ans.- North America is linked to South America by a very narrow strip of land called the Isthmus of Panama.

3. Name the smallest continent. By what other name do we often call it and why? 

Ans.- Australia is the smallest continent. It lies entirely in the Southern Hemisphere. It is also called Island continent because it is surrounded by water bodies from all four sides.

4. What are the three chief movements of ocean water?

Ans.-  The three chief movements of ocean water are- Ocean current, Tides and Waves

5. Why is Atlantic Ocean the busiest ocean? 

Ans.- Atlantic Ocean is between many trading ports from different countries from where trade and commerce related activities carried out that makes the Atlantic Ocean the busiest ocean.

6. How is a strait different from Isthmus?

Ans.- Strait – A strait is a narrow passage of water connecting two large water bodies like sea and oceans. 

Isthmus – A narrow strip of land joining two landmasses. 

7. Name the layers of the atmosphere according to height from the Earth‘s surface. 

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

8. What does the term global warming mean? 

Ans.- Carbon dioxide (CO2) emitted from industries, thermal power plants and vehicles, pollute the air. It is an important constituent of air. But increase in the amount of CO2 leads to increase in global temperatures. This is termed as global warming. 

9. What is atmosphere? Name the important gases it consists of. How are these gases important for living organisms? 

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

• The atmosphere is composed mainly of nitrogen and oxygen, which make up about 99 per cent of clean, dry air. Nitrogen 78 per cent, oxygen 21 per cent.
• Other gases like carbon dioxide, argon and others comprise 1 per cent by volume.
• Oxygen is the breath of life while nitrogen helps in the growth of living organisms.
• Carbon dioxide, though present in minute amount, is important as it absorbs heat radiated by the earth, thereby keeping the planet warm. It is also essential for the growth of plants.

10. What is biosphere? Mention the two main divisions of biosphere. Why is it one of the important domains of the earth? 

Ans.- Biosphere is the narrow zone where we find land, water and air together, which contains all forms of life.

The organisms in the biosphere may broadly be divided into the plant kingdom and the animal kingdom.

Importance

• It is in this zone that life, that is unique to this planet, exists. 
• There are several species of organisms that vary in size from microbes and bacteria to huge mammals. 
• All the living organisms including humans are linked to each other and to the biosphere for survival.

11. The surface of the earth is a complex zone. Explain.

Ans.-

• 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, carbon dioxide 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.

12. The three domains of the Earth (Lithosphere, Hydrosphere and Atmosphere) interact with each other and affect each other. Explain the statement with the help of examples. 

Ans.-

• The three domains of the earth interact with each other and affect each other in some way or the other. 
• For example, cutting of forests for fulfilling our needs of wood, or clearing land for agriculture may lead to fast removal of soil from slopes. 
• Similarly earth’s surface may be changed due to natural calamities like earthquakes. 
• For example, there could be submergence of land, as happened in the case of Tsunami recently. Parts of Andaman & Nicobar Islands were submerged under water. 
• Discharge of waste material into lakes and rivers makes the water unsuitable for human use. It also damages other forms of life.

13. Write notes on the seven major continents (Asia, Europe, Africa, North America, South America, Australia and Antarctica).

Ans.- There are seven major continents—Asia, Europe, Africa, North America, South America, Australia and Antarctica.

Asia

• Asia is the largest continent.
• It covers about one-third of the total land area of the earth.
• It 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.
• The combined land mass of Europe and Asia is called Eurasia (Europe + Asia).

Europe

• This continent lies to the west of Asia.
• The Arctic circle passes through it.
• It is bound by water bodies on three sides.

Africa

• It 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.
• It is the only continent through which the Tropic of Cancer, the Equator and the Tropic of Capricorn pass.
• It is bound on all sides by oceans and seas.
• The world’s largest hot desert, i.e. the Sahara Desert lies in this continent. The world’s longest river the Nile flows through it.

North America

• It 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.
• This continent lies completely in the Northern and Western Hemisphere.

South America

• It lies mostly in the Southern Hemisphere.
• The Andes, world’s longest mountain range, runs through its length from north to south.
• The world’s largest river, the Amazon flows through this continent.

Australia

• It is the smallest continent.
• It lies entirely in the Southern Hemisphere.
• It is also called Island continent because -It is surrounded by water bodies from all four sides.

Antarctica

• It lies completely in the Southern Hemisphere.
• It is a large continent.
• The South Pole lies almost at the centre of this continent.
• It is permanently covered with thick ice sheets because it is located in the South Polar Region.
• Permanent human settlement is not found here.