05. Major Domains of the Earth class 6 Chapter 5 Geography – NCERT Notes for CBSE

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Major Domains of the Earth

Chapter 5 Geography Class 6

In the first chapter, we learned that Earth is the only planet teeming with life. This is possible because Earth possesses the essential elements of life, including land, water, and air.

The Earth’s Complex Surface

The Earth’s surface is a complex arena where three main components of the environment – the lithosphere, the atmosphere, and the hydrosphere – meet, overlap, and interact. Here, we’ll explore these domains.

Keywords and Definitions:

• Lithosphere: The solid portion of Earth’s surface, consisting of rocks and thin soil layers that sustain life.
• Continents: Large landmasses on Earth’s surface.
• Ocean Basins: Vast areas of Earth’s surface covered by oceans.

Lithosphere

The solid portion of Earth’s surface that we inhabit is called the lithosphere. It comprises the rocks of Earth’s crust and the thin layers of soil that contain essential nutrients for sustaining life.

• Earth’s surface has two primary divisions: continents and ocean basins.
• All the world’s oceans are interconnected.

Are all the land masses connected with one another?

The level of seawater remains consistent globally, and land elevation is measured from sea level, which is taken as zero.

Word Origin: In Greek, “Lithos” means “Stone”; “Atmos” means “Vapour”; “Hudor” means “Water”; and “Bios” means “Life.”

Major Continents

There are seven major continents, separated by vast water bodies: Asia, Europe, Africa, North America, South America, Australia, and Antarctica.

• Asia, the largest continent, covers about one-third of Earth’s land area.
• Europe lies west of Asia and is smaller.
• Africa is the second-largest continent, with the Equator running through its heart.
• North America is the third largest, linked to South America by the Isthmus of Panama.
• South America mostly lies in the Southern Hemisphere.
• Australia, the smallest continent, is entirely in the Southern Hemisphere.
• Antarctica, a massive Southern Hemisphere continent, is permanently covered in ice and has no permanent human settlements.

Hydrosphere

Earth is often called the “blue planet” because over 71% of its surface is covered by water, with the remaining 29% being land. The hydrosphere includes water in various forms: oceans, rivers, lakes, glaciers, underground water, and water vapor in the atmosphere.

Keywords and Definitions:

• Hydrosphere: The sphere of Earth that consists of water in various forms, including oceans, rivers, glaciers, underground water, and atmospheric water vapor.
• Over 97% of Earth’s water is in the oceans and is too salty for human use.
• The rest includes ice sheets, glaciers, underground water, and a small percentage of fresh water available for human use.

Oceans

Oceans are the primary component of the hydrosphere and are interconnected. The major oceans, in order of size, are the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Southern Ocean, and the Arctic Ocean.

• The Pacific Ocean is the largest, covering one-third of Earth.
• The Atlantic Ocean is the second largest, characterized by its ‘S’ shape and highly indented coastline.
• The Indian Ocean is triangular in shape and named after India.
• The Southern Ocean surrounds Antarctica.
• The Arctic Ocean lies within the Arctic Circle, around the North Pole.

Atmosphere

The Earth is enveloped by a layer of gas called the atmosphere, which extends to about 1,600 kilometers in height. This atmosphere is crucial for life on our planet, providing breathable air and shielding us from the sun’s harmful rays.

Keywords and Definitions:

• Atmosphere: The gaseous layer surrounding Earth, essential for providing breathable air and protecting against solar radiation.
• The atmosphere is divided into five layers: troposphere, stratosphere, mesosphere, thermosphere, and exosphere.
• It mainly consists of nitrogen (78%) and oxygen (21%), with trace amounts of other gases like carbon dioxide.
• Carbon dioxide is essential for regulating Earth’s temperature and supporting plant growth.

Biosphere – The Domain of Life

The biosphere is the narrow zone where land, water, and air converge, hosting a diverse array of life forms. Organisms in the biosphere include plants and animals, from microorganisms to large mammals.

The domains of lithosphere, atmosphere, and hydrosphere interact and affect each other. Human activities, such as deforestation and pollution, can disrupt these domains and impact Earth’s delicate balance.

Frequently Asked Questions (FAQs)

1. What are the four major domains of the Earth?

• The four major domains are the lithosphere, atmosphere, hydrosphere, and biosphere.

2. Can you name the major continents of the Earth?

• The major continents are Asia, Europe, Africa, North America, South America, Australia, and Antarctica.

3. Which two continents lie entirely in the Southern Hemisphere?

• Australia and Antarctica are the two continents that lie entirely in the Southern Hemisphere.

4. What are the different layers of the atmosphere?

• The atmosphere has five layers: troposphere, stratosphere, mesosphere, thermosphere, and exosphere.

5. Why is Earth called the ‘blue planet’?

• Earth is called the ‘blue planet’ because over 71% of its surface is covered by water, giving it a blue appearance from space.

6. Why is the Northern Hemisphere called the Land Hemisphere?

• The Northern Hemisphere is called the Land Hemisphere because most of the Earth’s landmass lies in this hemisphere.

7. Why is the Biosphere important for living organisms?

• The Biosphere is crucial for life as it is the zone where land, water, and air converge, supporting a wide variety of life forms.

8. How do the lithosphere, atmosphere, and hydrosphere interact?

• These domains interact and affect each other, and human activities can disrupt their balance, leading to environmental issues.

9. What percentage of Earth’s water is found in the oceans?

• Over 97.5% of Earth’s water is found in the oceans.

10. What are some major oceans on Earth?

• The major oceans include the Pacific Ocean, Atlantic Ocean, Indian Ocean, Southern Ocean, and Arctic Ocean.

This comprehensive overview of Earth’s major domains provides insights into our planet’s complexity and the delicate balance that supports life as we know it.

This was the end of Major Domains of the Earth class 6 Chapter 5 Geography – NCERT Notes for CBSE.

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