Chapter 5 Major Domains of the Earth

Chapter Review: ▸ There are three main components of the environment – Lithosphere, Atmosphere and Hydrosphere.
▸ The solid portion of the Earth on which we live is called the Lithosphere.
▸ The gaseous layer that surrounds the Earth is the Atmosphere.
▸ The area covered by water is called the Hydrosphere.
▸ The zone which contains all forms of life is called Biosphere.
Lithosphere ▸ It comprises the rocks of the earth’s crust and the thin layers of soil.
▸ There are two main divisions of the earth’s surface.
▸ The large landmasses are known as the continents.
▸ The huge water bodies are called the ocean basins.
▸ Elevation of land is measured from the level of the sea, which is taken as zero.
▸ The highest mountain peak Mt. Everest is 8,848 metres above the sea level.
▸ The greatest depth of 11,022 metres has been recorded at Mariana Trench in the Pacific Ocean.
Continents ▸ There are seven major continents.
▸ The greater part of the land mass lies in the Northern Hemisphere.
▸ Asia is the largest continent.
▸ The combined landmass of Europe and Asia is called the Eurasia.
▸ Europe is much smaller than Asia.
▸ Africa is second largest continent. It is the only continent through which the Tropic of Cancer, the Equator and the Tropic of Capricorn pass.
▸ The world’s largest hot desert is the Sahara Desert.
▸ The world’s longest river is the Nile.
▸ North America is the third largest continent of the world.
▸ South America and North America are linked by a very narrow strip of land called the Isthmus of Panama.
▸ The world’s longest mountain range is the Andes.
▸ The Amazon is the world’s largest river.
▸ Australia is the smallest continent. It is also called an island continent.
▸ Antarctica is permanently covered with thick ice sheets.
▸ India has research station named as Maitri and Dakshin Gangotri at Antarctica.
Hydrosphere ▸ More than 71 % percent of the Earth is covered with water therefore the Earth is called the blue planet.
▸ More than 97% of the Earth’s water is found in the oceans.
Oceans ▸ The four major oceans are the Pacific Ocean, the Atlantic Ocean, the Indian Ocean and the Arctic Ocean.
▸ The Pacific Ocean is the largest ocean.
▸ The Atlantic Ocean is the second largest ocean.
▸ The Indian Ocean is the only ocean named after a country, that is India.
▸ The Arctic Ocean is located within the Arctic Circle.
Atmosphere ▸ Atmosphere 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—the troposphere, the stratosphere, the mesosphere, the thermosphere and the exosphere.
▸ The atmosphere is composed mainly of nitrogen and oxygen.
▸ Air moves from high pressure to low pressure. Moving air is known as wind.
Biosphere – The Domain of Life ▸ The biosphere is the narrow zone of contact between the land, water and air.
▸ All the living organisms including humans are linked to each other and to the biosphere for survival.
▸ The organisms in the biosphere may broadly be divided into the plant kingdom and the animal kingdom.
▸ Increase in the amount of CO2 leads to increase in global temperature. This is termed as global warming.

Textbook Questions


Question1. Answer the following questions briefly.
(a) What are the four major domains of the earth?
(b) Name the major continents of the earth.
(c) Name the two continents that lie entirely in the Southern Hemisphere.
(d) Name the different layers of atmosphere.
(e) Why is the earth called the ‘blue planet’?
(f) Why is the Northern Hemisphere called the land Hemisphere?
(g) Why is the biosphere important for living organisms?
Answer: (a) The four major domains of the earth are— Lithosphere, Atmosphere, Hydrosphere and Biosphere.
(b) Asia, Europe, Africa, North America, South America, Australia and Antarctica.
(c) Australia and Antarctica.
(d) Troposphere, Stratosphere, Mesosphere, Thermosphere and Exosphere.
(e) More than 71% of the earth is covered with water.
Hence, its is known as the ‘blue planet’.
(f) The greater part of the landmass lies in the Northern Hemisphere. Hence, it is called the land Hemisphere.
(g) Biosphere is important for living organisms because it is here that three essential elements of life (land, water and air) are found.


Question2. Tick the correct answer.
(a) The mountain range that separates Europe from Asia is
(i) the Andes (ii) the Himalayas
(iii) the Urals.
(b) The continent of North America is linked to South America by
(i) an Isthmus (ii) a Strait
(iii) a Canal.
(c) The major constituent of atmosphere by percent is
(i) Nitrogen (ii) Oxygen
(iii) Carbon dioxide.
(d) The domain of the earth consisting of solid rocks is
(i) the Atmosphere (ii) the Hydrosphere
(iii) the Lithosphere.
(e) Which the largest continent?
(i) Africa (ii) Asia
(iii) Australia
Answer: (a)—(iii), (b)—(i), (c)—(i), (d)—(iii), (e)—(ii).


Question3. Fill in the blanks.
(a) The deepest point on the earth is ……… in the Pacific Ocean.
(b) The ……… Ocean is named after a country.
(c) The ……… is a narrow contact zone of land, water and air that supports life.
(d) The continents of Europe and Asia together are known as ……… .
(e) The highest mountain peak on the earth is ……… .
Answer: (a) Mariana Trench, (b) Indian, (c) Biosphere, (d) Eurasia, (e) Mt. Everest.
THINGS TO DO


Question1. Cut the outline of the continents from an outline map of the world and arrange them according to their decreasing sizes.
Answer: For self-attempt.


Question2. Cut the outline of the continents from an outline map of the world and try to fit them together as a jig-saw puzzle.
Answer: For self-attempt.


Question3. Collect pictures of expeditions to the Himalayas. Write about the kind of equipment carried by the climbers for protection against sunshine, temperature and the lack of air.
Ans.
.
The mountaineers carry oxygen cylinders to be able to breath at high altitudes. They wear special jacket to avoid temperature. They also wear sunglasses and cap to save themselves from the scorching heat of the sun.
MAP SKILLS


Question1. On the outline map of the world, mark the following:
Europe, Asia, Antarctica, South America, Australia, Indian Ocean, Pacific Ocean, Atlantic ocean, Ural Mountains and Isthmus of Panama.
Ans.

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