REAMLS OF EARTH

Atmosphere surrounds the earth as a layer containing a mixture of gases. “Atmos” means air.

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Lithosphere ******It is the surface layer of the earth. It forms a thin crust of the earth. Lithos means rock.

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Hydrosphere***********It includes the vast oceans that cover about 71 percent of the earth’s surface. “Hydros” means Water.

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Biosphere*********It is the realm of living organisms.“Bios” means LIFE

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LITHOSPHERE

Lithosphere - is the rigid outermost shell of a rocky planet.

It comprises the crust and the portion of the upper mantle that behaves elastically on time scales of thousands of years or greater.

The Surface of the earth consists of soil & rocks.

This surface layer of the earth is called the CRUST or the LITHOSPHERE.

The crust includes both oceans & the land masses.

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Lithosphere is of great significance. This layer provides all the MINERALS

including metallic minerals such as iron, copper, gold, etc., to us.

Coal, natural gas & mineral fuels provide us energy. It also provides us non-metallic minerals such as limestone and gypsum.

This layer has soil on which all plants grow.

A fertile layer of soil is essential for good agricultural output to support human population.http://aparna-kidsstories.blogspot.in/

HYDROSPHERE

Hydrosphere - in physical geography describes the combined mass of water found on, under, and over the surface of a planet. 

Hydrosphere includes the vast oceans, seas, lakes, glaciers & polar ice sheet that cover 71 per cent of the earth’s surface, giving it the blue color. It includes saline as well as fresh water. The oceans contain 97 per cent of the total water present on the planet.

Oceans provide us with various minerals such as salt, manganese, bromine, etc.

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Fish & other organisms are rich source of food.

Oceans & rivers also provide a medium for transport by ships, boats etc.

Water on the earth is constantly in motion. It keeps changing from one form to other in a cyclical manner. It is called Water cycle or Hydrological cycle.

Water evaporates from the water bodies such as the oceans, lakes, ponds, etc.

THE HYDROLOGICAL CYCLE

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The water vapor rises to reach the upper layers of the atmosphere where it condenses due to cooling in the upper layers.

The CONDENSATION finally results in PRECIPITATION. This water seeps into the soil or flows down as rivers, finally joining back the oceans & seas.

The balance of water on earth thus remains constant over time through this cyclical process.

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ATMOSPHERE

Atmosphere surrounds the earth like an envelop of various gases. It is held together by the gravitational force of the earth.

Though the atmosphere extends beyond 1500 km above the earth, 97 per cent of it lies within 25 km from the earth’s surface. It is thus densest in the lower layers.

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The composition of the atmosphere : NITROGEN is most abundant gas in the

atmosphere. It comprises 78 per cent of the total volume of the air.

OXYGEN forms 21 per cent of the atmosphere. It is vital for the survival of the living beings on the earth.

The remaining 1 per cent consists of minute quantities of gases such as argon, carbon dioxide, etc. The atmosphere also contains dust particles and water vapor.

The atmosphere acts like a blanket protecting the earth from harmful rays of the sun especially the ozone layer. It maintains the optimum temperature which is essential for our survival on earth. http://aparna-kidsstories.blogspot.in/

BIOSPHERE

The Bioshere is the global sum of all ecosystems. It can also be termed the zone of life on Earth, a closed system (apart from solar & cosmic radiation & heat from the interior of the Earth) and largely self regulating.

The biosphere includes the parts of the atmosphere, lithosphere & hydrosphere in which living organisms exist. It contains organisms from tiny ones such as algae, fungi to higher organisms such as human beings.

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It involves close relationship & interdependence of all the other realms namely hydrosphere, atmosphere & lithosphere. All the requisites for life such as heat, water, air, food, habitat, etc., are found in this realm. It is thus called the “Realm of Life”

Biosphere is made of biotic or living environment and abiotic or non-living environment. These two interact with each other creating a balanced life supporting environment called an ecosystem.

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