Lithosphere: The lithosphere is the solid, rocky outer layer of the Earth that includes the crust and the upper part of the mantle. It is about 100 km thick and is broken into tectonic plates that move slowly over the asthenosphere. The lithosphere contains all landforms including mountains, plateaus, plains, and ocean basins.
Hydrosphere: The hydrosphere includes all the water on Earth's surface - in oceans, seas, rivers, lakes, glaciers, groundwater, and atmospheric water vapor. It covers about 71% of Earth's surface and plays a crucial role in regulating climate and supporting life.
According to the Continental Drift Theory proposed by Alfred Wegener, all the continents were once joined together in a single supercontinent called Pangaea during the late Paleozoic and early Mesozoic eras (about 335-175 million years ago).
Around 200 million years ago, Pangaea began to break apart into two large continental masses:
These landmasses gradually drifted to their current positions over millions of years.
The ocean floor has diverse topographic features similar to land surfaces:
Oceans (covering 71% of Earth's surface):
Continents (covering 29% of Earth's surface):
Major landforms on Earth's surface:
Physical characteristics of Asia:
(a) Why do 90 per cent of the world's total population concentrate in the northern hemisphere?
Reasons:
(b) What is the reason behind lack of permanent human settlement in Antarctica?
Reasons:
(a) Which has created a natural boundary between Asia and Europe?
The Ural Mountains, Ural River, Caspian Sea, and Caucasus Mountains form the natural boundary between Asia and Europe.
(b) Which is the longest mountain range of the world and where it is located?
The Andes Mountains in South America, stretching about 7,000 km along the western coast.
(c) In terms of land area which are the largest and smallest countries of the world?
Largest: Russia (17.1 million sq km)
Smallest: Vatican City (0.44 sq km)
(d) Which country of the world is spread to two continents?
Russia (Europe and Asia) and Turkey (Europe and Asia)
(e) In terms of population which are the largest and smallest countries of the world?
Largest: China and India (over 1.4 billion each)
Smallest: Vatican City (about 800 people)
(f) What is the name of the major mountain range of North America? In which part of the continent is it located?
The Rocky Mountains, located in western North America.
(g) Which is the world's largest desert and where is it located?
The Sahara Desert in northern Africa, covering about 9.2 million sq km.
(h) Write the names of two northerly and two easterly rivers of Asia.
Northerly: Ob River, Yenisei River
Easterly: Yangtze River, Amur River
(i) Write the names of one each of major mountain range, river and desert of Australia.
Mountain Range: Great Dividing Range
River: Murray River
Desert: Great Victoria Desert
(j) Write the names of three countries of Europe located in the Mediterranean region.
Spain, Italy, Greece
(a) Pangaea
Pangaea was a supercontinent that existed during the late Paleozoic and early Mesozoic eras, comprising almost all of Earth's landmass. It began breaking apart about 200 million years ago, eventually forming the continents we know today.
(b) Arctic Ocean
The smallest and shallowest of the world's oceans, located around the North Pole. It is mostly covered by sea ice and is bordered by northern parts of North America, Europe, and Asia.
(c) The Continent of Oceania
Also known as Australia, it is the smallest continent comprising Australia, New Zealand, Papua New Guinea, and numerous Pacific islands. It's known for unique wildlife and diverse landscapes.
(d) The rivers of Asia
Asia has some of the world's longest rivers including Yangtze, Yellow River, Ganges, Indus, Brahmaputra, Mekong, and Ob. These rivers support agriculture and civilizations.
(e) The lakes of Africa
Africa has several significant lakes including Lake Victoria (largest in Africa), Lake Tanganyika (second deepest in world), Lake Malawi, and Lake Chad.
(f) The rivers of Europe
Major European rivers include Volga (longest), Danube, Rhine, Seine, Thames, and Po. These rivers have been crucial for trade and transportation.
(g) The Appalachian Highland Region
A mountain range in eastern North America extending from Newfoundland to Alabama. It's one of the oldest mountain ranges with rich mineral resources.
(h) The lakes of North America
Includes the Great Lakes (Superior, Michigan, Huron, Erie, Ontario - largest freshwater system), Great Salt Lake, and Lake Winnipeg.
(a) Continental shelf and Continental slope
| Continental Shelf | Continental Slope |
|---|---|
| Gently sloping submerged edge of continent | Steep slope descending from continental shelf |
| Depth: Up to 200 meters | Depth: 200 to 4000 meters |
| Width: 70-80 km average | Narrower than continental shelf |
| Rich in marine life and mineral resources | Transition zone to deep ocean floor |
(b) Everest Peak and Godwin Austin Peak
| Mount Everest | K2 (Godwin Austin) |
|---|---|
| Highest peak in world (8,848 m) | Second highest peak (8,611 m) |
| Located in Mahalangur Himal, Nepal/China | Located in Karakoram Range, Pakistan/China |
| More climbed despite being higher | Considered more difficult and dangerous to climb |
| Death rate: About 4% | Death rate: About 25% |
(c) The Continent of Oceania and the Continent of Antarctica
| Oceania | Antarctica |
|---|---|
| Smallest continent by land area | Fifth largest continent |
| Permanent human population | No permanent human population |
| Various climates from tropical to temperate | Coldest continent, entirely covered by ice |
| Rich biodiversity | Limited terrestrial life, rich marine life |
(d) Gobi desert and Atacama desert
| Gobi Desert | Atacama Desert |
|---|---|
| Located in East Asia (Mongolia/China) | Located in South America (Chile/Peru) |
| Cold desert with extreme temperatures | Hot desert, driest non-polar desert |
| Area: About 1.3 million sq km | Area: About 105,000 sq km |
| Known for dinosaur fossils | Known for salt flats and copper mines |
(a) Which is the world's second largest ocean?
(1) Pacific Ocean (2) Indian Ocean (3) Atlantic Ocean (4) Southern Ocean
Answer: (3) Atlantic Ocean
(b) Which is smallest continent of the world?
(1) North America (2) Europe (3) Antarctica (4) Oceania
Answer: (4) Oceania
(c) In which ocean Falkland island is located?
(1) Atlantic Ocean (2) Arctic Ocean (3) Pacific Ocean (4) Indian Ocean
Answer: (1) Atlantic Ocean
(d) Which sea has separated the continents of Asia and Africa?
(1) Mediterranean Sea (2) Red Sea (3) Caspian Sea (4) Arabian Sea
Answer: (2) Red Sea
(e) What has naturally separated Asia from Europe?
(1) Ural mountain range (2) Caucasus mountain (3) Caspian Sea (4) Volga river
Answer: (1) Ural mountain range
(f) In which continent is Ecuador located?
(1) North America (2) South America (3) Africa (4) Asia
Answer: (2) South America
(g) What is the capital of Brazil?
(1) Rio de Janeiro (2) Sao Paulo (3) Brasília (4) Lima
Answer: (3) Brasília