22-10-2012, 01:19 PM
To study of environment.
environment..ppt (Size: 1.2 MB / Downloads: 35)
How was earth formed ?
The earth is formed about 4.8 billion years ago.
The first sign of life have appeared about 3.8 billion years ago.
The first multicellular organisms appeared about 1.4 billion years ago.
These organisms and other forms of life could survive when the conditions on earth, began to stabilize gradually.
Hydrosphere.
71% of the earth is covered with water.
The part of the earth that is covered with water is called hydrosphere.
Earth is the only planet in the solar system with abundant liquid water and this one of the factors responsible for making life possible on the Earth.
Atmosphere
Atmosphere is nothing but the mixture of gases, water vapour and fine dust surrounding the earth.
Nearly about 78% of the atmosphere is only nitrogen.
About 21% of the atmosphere is oxygen.
Rest of them are carbon-di-oxide, argon and other types of gases.
Lithosphere
The surface of the earth is called lithosphere.
Lithosphere forms the mountains, ocean floors and the plain lands.
Lithosphere allows life to flourish unlike the barren surface of other planets.
Biosphere
Hydrosphere, atmosphere and lithosphere of the Earth together constitute the Biosphere.
Biosphere is the sum total of all organism and their places of living.
Biosphere extends only a few kilometers below the surface and extends only a few kilometers into the atmosphere.
Ecology
The scientific studies which enable us to understand the totality and pattern of the relations between organisms and their environment is called Ecology.
Ecology is also known as environmental science.
The two basic laws of ecology are:-
1)We can never continue to do any one thing in nature.
2)In the nature everything is connected with everything else.