Major Domains of the Earth – CBSE Notes for Class 6 Social
Facts that Matter:
• The earth is the only planet where human beings find three life sustaining elementsâ€”
land, water and air.
• The surface of the earth is a complex zone. Here three main components of the environmentâ€”lithosphere, atmosphere and hydrosphere meet, overlap and interact.
• The lithosphere refers to the solid portion of the earth where we live.
• The atmosphere refers to the gaseous layers which surrounding the earth.
• The hydrosphere refers to the water bodies that exist on the earth’s surface.
• Biosphere is the narrow zone where we find land, water and air together. Life exists here.
• The earth’s surface is divided into continents and ocean basins.
• Continents are large landmasses of the earth while ocean basins are huge water bodies.
• Mount Everest is the highest mountain peak. Its height is 8,848 metres above the sea level.
• The greatest depth of 11,022 metres is recorded at Mariana Trench in the Pacific Ocean.
• There are seven continentsâ€”Asia, Europe, Africa, North America, South America, Australia and Antarctica.
• Asia is the largest continent while Australia is the smallest continent.
• Antarctica is permanently covered with thick ice sheets. Hence, it is not suitable for human settlement.
• More than 71% of the earth is covered with water and 29% is with land.
• More than 97% of the earth’s water is found in the oceans. Ocean water is salty. It is of no human use. A large proportion of the rest of the water is in the form of ice sheets and glaciers or under the ground. Only 0.03% of water is available as fresh water which is usable by human beings.
• There are four major oceansâ€”the Pacific Ocean, the Atlantic Ocean, the Indian Ocean and the Arctic Ocean in order of their size.
• The Indian Ocean is the only ocean named after a country, i.e. India.
• The atmosphere is divided into five layers. These layer starting from earth’s surface
areâ€”the troposphere, the stratosphere, the mesosphere, the thermosphere and the exosphere.
• The atmosphere is composed of several gasesâ€”Nitrogen (78%), Oxygen (21%), other gases like carbondioxide, argon and others comprise 1%.
• Oxygen is essential for our life. We can not live without it. Nitrogen is essential for the growth of living organisms. Carbondioxide absorbs heat radiated by the earth and in this way it keeps the earth warm. It is also essential for plants.
• Biosphere is the zone where life exists. From tiny microbes and bacteria to huge mammals are found in the biosphere. There is a close link between all these organisms including humans.
• The organisms in the biosphere are divided into plant kingdom and the animal kingdom.
• The three domains of the earth interact with each other and affect each other. For example: emission from industries pollute the air.
• Increase in the amount of C02 leads to increase in global temperatures which is known as global warming.
Words that Matter :
• Lithosphere: The solid portion of the earth on which we live is termed as the lithosphere.
• Atmosphere: The gaseous layers that surround the earth is known as the atmosphere.
• Hydrosphere: The water bodies on the earth’s surface is known as hydrosphere.
• Biosphere: It is the narrow zone where land, water and air together are found. All forms of life exists here.
• Continents: The large landmasses are called continents.
• Ocean basins: The huge water bodies are called the ocean basins.
• Strait: It is a narrow passage of water connecting two large water bodies like seas and oceans.
• Isthmus: It is a narrow strip of land joining two landmasses.
• Plant Kingdom: The part of biosphere consisting of plants and trees.
• Animal Kingdom: The part of biosphere consisting of animal.
• Global warming: Increase in the amount of carbon dioxide leads to increase in the global temperatures. This is known as global warming.