WBBSE Solutions For Class 6 Geography Chapter 5 Water Land Air Topic B Continental Drift And Introduction Of Oceans

Class 6 Geography WBBSE Chapter 5 Water Land Air Topic B Continental Drift And Introduction Of Oceans Analytical Type Questions

Question 1. Give an idea of continental drifting.
Answer:

The Theory of Continental Drift is discussed below:

Proponents: The speculation that the continents might have drifted was first proposed by Abraham Ortelius in 1596. Alfred Wegener formulated the Theory of Continental Drift in 1912.

Hypothesis: Wegener believed that around 500 million years ago there was only one supercontinent known as ‘Pangaea’ or ‘Pangea7 and the surrounding was a huge water mass known as ‘Panthalassa’.

Drifting of the continents: Around 200 million years ago Pangaea started breaking apart. Pangaea broke up into two huge landmasses known as ‘Laurasia’ and ‘Gondwanaland’.

Continent disintegration continued and the disintegrated parts floated and moved around in all directions due to the convection current.

This drifted apart disintegrated parts finally resulted in landmasses that look like our modern-day continents.

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Evidence: Wegener supplemented his theory with various pieces of evidence, which are as follows:

1. A jigsaw fit is possible if all the continents are arranged together.
2. There are similarities between the eastern coast of South America and the western coast of Africa.
3. Similar plant and animal fossils have been found on different continents proving that they were once together.

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Question 2. Jot down the typical features of the distribution of land and water on Earth.
Answer:

The typical features of the distribution of land and water on Earth are as follows—

Features of distribution of land: Features of distribution of land are as follows—

1. The continents or the land surface occupy only one-fourth part of the Earth’s surface.
2. The topography of the continents is continuously changing due to mountain building, weathering, sedimentation, etc.
3. The continents are surrounded by oceans.
4. The proportion of land and water is almost equal in the northern hemisphere.
5. The southern hemisphere has 15% more water mass than landmass.
6. There are 7 continents on Earth. Mt. Everest (8848m) in Asia is the highest point in the world.

Features of distribution of water: Features of distribution of water are as follows—

1. The oceans or the water surface occupy three-fourth parts of the surface of Earth.
2. 97% of the water content on the Earth’s surface is present in the oceans.
3. The oceans are linked to each other and thus the level of the water surface is the same throughout the world.
4. There was only one super ocean called the Panthalassa in the past, which surrounded all the continents. Currently, there are 5 oceans on Earth.
5. Challenger Deep at Mariana Trench (10.91km) in the Pacific Ocean is the deepest point on Earth.

Question 3. Discuss the special characteristics of continents and oceans.
Answer:

The special characteristics of continents and oceans:

If we look closely at the world’s map, the same special characteristics of continents and oceans are visible.

Characteristics of continents:

Areal extent: About 29% of the Earth’s surface area belongs to the continent.

Hemisphere-wise extent: Most of the world’s continents are located in the Northern Hemisphere. About 39% of the surface area of the northern hemisphere and 19% of the surface area of the southern hemisphere belong to the landmass or continents.

Circular location: The continents are located almost circularly in the Northern Hemisphere, centered around the Arctic Circle.

Continents: The land area of the world consists of seven continents, viz. Asia (largest), Africa, North America, South America, Antarctica, Europe, and Oceania.

Uneven Surface: The surface of the continents is uneven, Mountains, plateaus, plains, etc. bring physiography diversity to this land.

Mount Everest (8848 m) is the highest part of the world and the Asia continent is the largest landmass.

Class 6 Geography WBBSE Characteristics of Oceans:

Areal Extent: About 71% of the Earth’s surface area belongs to water bodies or Oceans.

Hemisphere-wise extent: Most of the world’s Oceans are located in the Southern Hemisphere. About 61% of the northern hemisphere and 81% of the southern hemisphere are under the water bodies.

Directional extent: The Oceans are narrow to the north but wide to the south. The oceans again extend in an east-west direction.

Oceans: There are five oceans in the world. They are the Pacific Ocean (the largest, with an area greater than the total landmass of the Earth), the Atlantic Ocean the Indian Ocean, the Antarctic Ocean, and the Arctic Ocean.

Uneven sea floor: The bottom of the sea is uneven, steep, and mountainous. The Mariana Trench (10915 m) in the Pacific Ocean is the deepest part of the world.

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Chapter 5 Water Land Air Topic B Continental Drift And Introduction Of Oceans Short Analytical Type Questions

Question 1. What is a jigsaw fit?
Answer:

Jigsaw fit:

The Theory of Continental Drift proposed by Alfred Wegener suggests that in ancient times, all the continents formed a single, huge landmass known as ‘Pangaea1.

Around 200 million years ago, Pangaea had begun to break apart. As evidence of this theory, he cited an example.

He said that the western coast of Africa and the eastern coast of South America if joined together, will make an exact fit like a jigsaw fit puzzle.

Question 2. Discuss the Theory of Continental Drift.
Answer:

The Theory of Continental Drift:

In 1912 Alfred Wegener talked about the Theory of Continental Drift. Wegener believed that around 500 million years ago there was only one supercontinent known as ‘Pangaea’ and surrounding it was a huge water mass known as ‘Panthalassa’.

About 200 million years ago Pangaea broke up into two huge landmasses known as ‘Laurasia’ and ‘Gondwanaland’.

Further breaking up of the disintegrated land masses and their drifting apart due to convection currents resulted in land masses that look like our modern-day continents.

Question 3. Write a short note on Pangaea and Panthalassa.
Answer:

Pangaea and Panthalassa:

The Theory of Continental Drift proposed by Alfred Wegener suggests that in ancient times, all the continents together formed a single, huge landmass or supercontinent.

This was given the name Pangaea from two ancient Greek words – ‘Pan’ meaning ‘AH’ and ‘Gaia’ meaning ‘Earth’.

The corresponding single global ocean that surrounded the Pangaea is known as Panthalassa. This name also originates from two ancient Greek words – ‘Pan’ meaning ‘AH’ and ‘Thalassa’ meaning ‘sea’.

 

 

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Question 4. Write about Asia’s location on Earth and Its geographical stretch.
Answer:

Asia’s location on Earth and Its geographical stretch:

In terms of surface area and population, Asia is the world’s largest continent.

1. Location: Longitudinal extent 26°04’E to 169°40’W latitudinal extent l°16’Sto 77°43’N.
2. Surface area: 4,45,79,000 square km.

Borders:

1. North: Arctic Ocean
2. South: Indian Ocean, Red Sea
3. East: Pacific Ocean
4. West: Ural mountain ranges, Ural River, Caspian Sea, and the Black Sea.

Question 5. Write a note on the geographic diversity of Asia.
Answer:

The geographic diversity of Asia:

Asia is the world’s largest continent. Naturally, it has a great diversity of geography that can best be explained through a table.

This is as follows:

 

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Question 6. Write about the areal extent and the geographical stretch of Africa.
Answer:

The areal extent and the geographical stretch of Africa:

Africa is the world’s 2nd largest continent.

1. Location: Longitudinal extent—17°33’W to 51°24’E; latitudinal extent— 37°20’N to 34°52’S.
2. Surface area: 3,03,70,000 square km.

Borders:

1. North: Mediterranean Sea;
2. South: Indian Ocean;
3. East: Red Sea, Indian Ocean;
4. West: Atlantic Ocean.

Question 7. Write about the Geographical diversity of Africa.
Answer:

The diversity of Africa can best be explained through the following table-

Question 8. Write a note on North America’s areal extent of its’s geographical stretch.
Answer:

North America’s areal extent of its’s geographical stretch:

North America is the world’s third-largest continent. In terms of surface area, it is almost 7 times that of India and 2.5 times that of Europe.

Location: Longitudinal extent—20°W to 173° W; latitudinal extent—7°N to 84°N.
Surface area: 2,47,10,000 square km.

Borders:

1. North: Arctic Ocean, Bering Strait;
2. South: Panama Canal, Pacific Ocean;
3. East: Atlantic Ocean;
4. West: Pacific Ocean.

Question 9. List the special geographical characteristics of North America.
Answer:

The Diversity Of North America Can Best Be Explained Through The Following Table—

Question 10. Write about South America’s areal extent and its geographical stretch.
Answer:

South America’s areal extent and its geographical stretch:

South America is the world’s fourth-largest continent. This is where the ancient Mayan civilization flourished. In terms of surface area, it is almost 5 times that of India and 2 times that of Europe.

1. Location: Longitudinal extent—34°50’W to 81°20’W; Latitudinal extent-12°28, N to 55°59’S.
2. Surface area: 1,78,40,000 square km.

Borders:

1. North and East: Atlantic Ocean;
2. South: Southern Ocean;
3. West: Pacific Ocean.

Question 11. Write about the special geographical characteristics of South America
Answer:

The Diversity of South America can best be explained through the following table-

Question 12. Write a note on the continent of Antarctica.
Answer:

The continent of Antarctica:

Antarctica is the world’s fifth-largest continent surrounding the south pole. This is the highest, driest, and coldest among all the continents.

In 1821, John Davis was the first to set foot on this landmass. The average height of this continent is about 2500m and without the covering of snow and ice, about 1830m.

A few of the characteristic features of Antarctica are as follows—

Question 13. Write a note on the continent of Europe.
Answer:

The continent of Europe:

Europe is the world’s sixth-largest continent. This together with Asia forms a continuous landmass called Eurasia.

A few characteristic features of Europe are as follows—

Question 14. Write a note on the continent of Oceania
Answer:

The continent of Oceania:

Oceania is the world’s smallest island continent. Australia and New Zealand are the main countries. This continent includes several groups of islands as well.

Question 15. Write a comparison between continents and oceans
Answer:

The comparison between continents and oceans is as follows—

Question 16. What are the differences between landmass and water mass?
Answer:

The differences between landmass and water mass are as follows—

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Question 17. What could be the position of the continents in the future?
Answer:

The position of the continents in the future:

According to the concept of continental drift, the continents of the Earth are still is a moving state.

Observations from the artificial satellites have shown that the continents are moving away by 2-20 cm a year.

According to this calculation, this movement of the continents after millions of years is going to make a major change in the map of the world, such as-

North and South America will move further west and push the Asian landmass in the next 100 million years.

As a result, the Atlantic Ocean will grow in size and there will be no such thing as the Pacific Ocean.

The eastern part of Africa will move further northeast and join with the Indian subcontinent.

Question 18. Why are the continents not stable?
Answer:

The continents not stable:

The current created in the mantle by the intense heat inside the Earth is called convention current. The continents are in motion because of this current.

As a result, the Pangea had broken and the continents had become active.

As the circulating current is still active in the mantle, the plates floating on the mantle (asthenosphere) move as a result of this current.

That means the continents that are located on these plates are also moving. It has been observed from the artificial satellites that the continents are moving by 2-20 cm per year

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Chapter 5 Water Land Air Topic B Continental Drift And Introduction Of Oceans Short Answer Type Questions

Question 1. What are ’Pangaea’ and ’Panthalassa’ ? 1
Answer:

Pangaea’ and ’Panthalassa’:

Pangaea: The word ‘Pangaea7 is derived from the Greek word meaning ‘all Earth’. According to Alfred Wegener, in ancient times all the continents were fused into a single, huge landmass known as Pangaea.

Panthalassa: ‘Panthalassa means ‘all sea’. The gigantic waterbody or super ocean that surrounded the Pangaea is known as Panthalassa.

Question 2. What is a convection current?
Answer:

Convection current:

The current created by the flow of molten magma in the interior of the Earth (mantle) is called the convection current.

Arthur Holmes was the first person to talk about the convection current. According to Holmes, it is because of this convection current the Lithospheric plates move Long the direction of the current.

 

Chapter 5 Water Land Air Topic B Continental Drift And Introduction Of Oceans Multiple Choice Questions

Question 1. The drift of the continents from their previous position is called the—

1. Continental drift
2. Continental shift
3. Continental movement

Answer: 1. Continental drift

Question 2. About 270 million years ago, there was only one landmass or supercontinent on the earth and this was called—

1. Pangaea
2. Panthalassa
3. Geosyncline

Answer: 2. Pangaea

Question 3. Is the world’s largest continent.

1. Europe
2. Asia
3. Africa

Answer: 2. Asia

Question 4. The continent where the temperature is always at or below the freezing point is—

1. North America
2. South America
3. Antarctica

Answer: 3. Antarctica

Question 5. Is the world’s smallest continent.

1. Asia
2. Oceania
3. Africa

Answer: 2. Oceania

Question 6. The largest ocean in the world is—

1. Pacific Ocean
2. Atlantic ocean
3. Indian Ocean

Answer: 1. Pacific Ocean

Question 7. The smallest ocean on earth is—

1. Arctic Ocean
2. Antarctic ocean
3. Indian Ocean

Answer: 1. Antarctic ocean

Question 8. The highest mountain on earth is—

1. Everest
2. Aconcagua
3. Kilimanjaro

Answer: 1. Everest

Question 9. The longest mountain range on earth is the—

1. Himalayas
2. Andes
3. Alps

Answer: 2. Andes

Question 10. The longest river in the world is—

1. Amazon
2. Nile
3. Mississippi

Answer: 2. Nile

Question 11. The largest river in the world in terms of area is—

1. Amazon
2. Nile
3. Mississippi

Answer: 1. Amazon

Question 12. The fourth largest river system in the world is—

1. The ganga-brahmaputra
2. The Mississippi-Missouri
3. The rhine-ruhr

Answer: 2. The Mississippi-Missouri

Question 13. The southern hemisphere has more water than the northern hemisphere.

1. 10%
2. 15%
3. 75%

Answer: 2. 15%

 

Chapter 5 Water Land Air Topic B Continental Drift And Introduction Of Oceans Fill In The Blanks

Question 1. The Continent of Africa has __________ Countries.
Answer: 54

Question 2. The driest cold desert on Earth is __________ in South America.
Answer: Sahara

Question 3. The driest hot desert on Earth is __________ in Africa.
Answer: Pacific

Question 4. __________ Ocean is actually the confluence of the southern parts of the Pacific, Atlantic, and Indian Oceans.
Answer: Patagonia

Question 5. Almost half of the Earth’s volume is taken up by the__________ Ocean.
Answer: Antarctic

Question 6. The percentage of land on Earth is about__________
Answer: 29

 

Chapter 5 Water Land Air Topic B Continental Drift And Introduction Of Oceans Write True Or False

Question 1. India is a part of the continent of Africa.
Answer: False

Question 2. The Alps Mountain range is in Europe.
Answer: True

Question 3. The single landmass or supercontinent that existed in ancient times is called the Panthalassa.
Answer: False

Question 4. The largest desert on Earth is the Thar.
Answer: False

Question 5. The deepest ocean on Earth is the Antarctic Ocean.
Answer: True

Question 6. The longest river in Asia is the Yang Tse Kiang.
Answer: False

Question 7. The percentage of water on Earth is 71.
Answer: True

Question 8. Antarctica is a continent with no permanent human settlement.
Answer: True

 

Chapter 5 Water Land Air Topic B Continental Drift And Introduction Of Oceans Match The Columns

 

Answer: 1-E,2-C3-F,4-A,5-G,6-H,7-B,8-D

 

Answer: 1-K,2-H,3-I,4-A,5-G,6-L,7-J,8-E,9-C,10-B,11-F,12-D

 

Chapter 5 Water Land Air Topic B Continental Drift And Introduction Of Oceans Answer In One Or Two Words

Question 1. How many years ago did the Earth have only one huge landmass or supercontinent?
Answer: Almost 500 million years.

Question 2. When did the continents start drifting away from each other?
Answer: Almost 200 million years ago.

Question 3. What percentage of the Earth’s surface is made up of land?
Answer: 29 percent.

Question 4. How many continents are there on Earth?
Answer: Seven.

Question 5. How many oceans are there on Earth?
Answer: Five.

Question 6. How many countries are there in Asia?
Answer: 44.

Question 7. Which is the largest continent on Earth?
Answer: Asia (The surface area is about 4,45,79,000 sq km).

Question 8. Of which continent is India a part?
Answer: Asia.

Question 9. How many countries are there in Europe?
Answer: 45.

Question 10. Which other continent is Europe attached to?
Answer: Asia.

Question 11. In which hemisphere is North America located?
Answer: Northern Hemisphere.

Question 12. Which is the highest peak in South America?
Answer: The Aconcagua [in the Andes Range, 6962 m].

Question 13. In which continent is the Amazon?
Answer: South America.

Question 14. Which is the world’s driest cold desert?
Answer: Patagonia.

Question 15. Which type of mountain range are the Andes?
Answer: Young Fold mountain range.

Question 16. Which is the second-highest mountain range on Earth?
Answer: The Andes.

Question 17. What type of volcano is Aconcagua?
Answer: Extinct volcano.

Question 18. In which continent is the world’s longest river?
Answer: Africa.

Question 19. Which Is the world’s largest hot desert?
Answer: Sahara (the area is almost 9.2 million sq miles).

Question 20. Which Is the southernmost continent on Earth?
Answer: Antarctica.

Question 21. Which Is the smallest ocean on Earth?
Answer: Arctic Ocean.

Question 22. Which is the deepest ocean on Earth?
Answer: Pacific Ocean (the deepest point is almost 11 km below sea level).

Question 23. In which hemisphere is the volume of land- mass and water mass almost the same?
Answer: Northern Hemisphere.

Question 24. Which hemisphere has more water?
Answer: Southern Hemisphere.