The biosphere is defined as the part of earth which is habituated. The atmosphere consists of both the biotic and abiotic components. The biosphere is also known as living mantle. This idea came into function 100 year ago. It was rejected than and its importance was come to known recently. The Austrian geologist Eduar Suess played a vital role in this regard. The thickness of biosphere is around 22 and half a kilometer from the bottom of ocean and extends till the top of mountains. Some part of the biosphere are occupied more and some are less. The maximum density of the organisms occurs in the tropical rain forests along with the coral reef. The life on the live volcanoes does not exist. There are very few organisms which occur on the tundra region, in snow capped Himalayas, deserts and the hot springs.
There are different subdivisions of biosphere.
These are known as :-
1. Hydrosphere
2. Lithosphere
3. Atmosphere.
They interact with each other and do not occur alone. They provide a crucial role in the existence of organisms. The lithosphere is the solid part of earth. It forms the continents and the land masses. It is mainly composed of the rocks and soil. It is rich in minerals. It is about 20 kilometer in the thickness. The area which is uncovered is the area which provides the exchange of minerals with the living world. The hydrosphere is the liquid part of earth. It forms the oceans, sea, lakes, rivers and ponds etc. The survival of aquatic animals depends on water. The seas and oceans occupy nearly ¾ th area of earth. Their salt content is high. There is a little salt content in the fresh water. The atmosphere is the gaseous part of earth. It form the gases such as nitrogen, oxygen, carbon dioxide and other few gases along with the dust and water particles. They cover the lithosphere and hydrosphere. The nitrogen is the most abundant gas which is followed by the other gases. The atmosphere extends many kilometers and is divided into many parts. It consists of the troposphere, stratosphere, ozonosphere and ionosphere. The troposphere is important to biosphere and the rest of layers act as an ozone layer which remove the U.V rays and other harmful waves.These subdivisions are essential for the survival of living beings.
