LITHOSPHERE – CONTINENTS AND OCEANS BASINS
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 that sustain organisms.
There are two main divisions of the earth’s surface. The large landmasses are known as the continents and the huge water bodies are called the ocean basins. All the oceans of the world are connected with one another. Look at the map of the world (Figure 5.1). Are all the landmasses connected with one another?
The level of seawater remains the same everywhere. The elevation of the land is measured from the level of the sea, which is taken as zero. The highest mountain peak Mt. Everest is 8,848 meters above the sea level. The greatest depth of 11,022 meters is recorded at Mariana Trench in the Pacific Ocean. Could you imagine that the depth of the sea is much more than the highest point?
Do you know?
1.Edmund Hillary (New Zealand) and Tenzing Norgay Sherpa (India) were the first men to climb the highest mountain peak Mt. Everest on the planet earth on 29th May 1953.
2.Junko Tabei (Japan) was the first woman to reach the summit on 16th May 1975.
3.The first Indian woman to climb the highest peak on 23rd May 1984 was Bahendri Pal.
Continents
There are seven major continents. These are separated by large water bodies. These continents are – Asia, Europe, Africa, North America, South America, Australia, and Antarctica. Look at the map of the world (Figure 5.1) and notice that the greater part of the landmass lies in the Northern Hemisphere.
Activity:
Let’s Do
Count the squares given in Figure 5.3 and answer the following:
Name the largest continent; (b) Which is larger – Europe or Australia?
Source: This Topic is taken from NCERT TEXTBOOK
ASIA, EUROPE
Asia is the largest continent. It covers about one-third 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 (Figure 5.1). The combined landmass of Europe and Asia is called Eurasia (Europe + Asia).
Europe is much smaller than in Asia. The continent lies to the west of Asia. The Arctic Circle passes through it. It is bound by water bodies on three sides. Look at the map of the world and locate it.
Source: This Topic is taken from NCERT TEXTBOOK
AFRICA
Africa is the second-largest continent after Asia. The Equator or 00 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.
The Sahara Desert, the world’s largest hot desert, is located in Africa. The continent is bound on all sides by oceans and seas. Look at the world map (Figure 5.1). You will notice that the world’s longest river the Nile, flows through Africa. Notice where the Equator, the Tropic of Cancer, and the Tropic of Capricorn pass in the map of Africa.
Source: This Topic is taken from NCERT TEXTBOOK
NORTH AMERICA AND SOUTH AMERICA
North America is the third largest continent in 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. Can you name these oceans?
South America lies mostly in the Southern Hemisphere. Which two oceans surround it on the east and the west? The Andes, the world’s longest mountain range, runs through its length from north to south (Figure 5.2). South America has the world’s largest river, the Amazon.
Source: This Topic is taken from NCERT TEXTBOOK
AUSTRALIA AND ANTARCTICA
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.
Antarctica, completely in the Southern Hemisphere, is a huge continent. The South Pole lies almost at the center 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.
Source: This Topic is taken from NCERT TEXTBOOK