Biosphere: Definitions, Important Terms, Extent and Importance of Biosphere

Biosphere definitions extent and importance in this basic and important concept of bio-geography we will study in detail about the biosphere and its definitions, then we study about technical terms of biosphere, also about extent of biosphere and lastly about the importance of biosphere etc…

Biosphere: Definitions, Important Terms, Extent and Importance of Biosphere

Table of Content

  • Introduction
  • Technical Terms
  • Extent of the Biosphere
  • Biosphere- Importance of Plants and Animals





Before evolution of life the earth was like a big desert. It was a rocky sphere on which there were shallow oceans and around which there was a thin layer of gases. In this way there were only three spheres on earth-Lithosphere, Hydrosphere and atmosphere. It was lifeless earth called the geosphere. Then life originated and evolved over millions of years and a thin layer of life appeared on the lifeless planet. This was how the biosphere or an area of life was founded on earth.


Biosphere is that part of lithosphere, hydrosphere and atmosphere where plants and human beings live. It is a thin layer of organisms. Organisms need solar energy, water and many nutrients their life and growth.


Biosphere contains all life forms on earth. This is not only dependent on atmosphere (air), hydrosphere (water) and lithosphere (soil and rocks) but also interact with them.


Glossary of Technical Terms

Biosphere:All the lifeforms of earth and their physical environment with which they interact is called biosphere.

Ecology:The branch of science concerned with the relations of organisms with each other and with their physical environment.

Environment:All the living and non-living things forming the surroundings of an animal or a plant. The lifeforms operates within this environment.

Ecosystem:The blological community of interacting organisms and with their environment.


In the biosphere there are a variety of forms of colourful life. The life includes all sorts of lifeforms from tiny organisms which cannot be seen with the naked eyes to the giant animals like whale and many huge trees. The biosphere supports plants, animals, fungus, single celled bacteria etc. ranging in species from 50 lakhs to 10 crores. Among these so far 15 lakhs to17.5 lakhs have been identified and indexed. Among these more than the half are insects.



Extent of the Biosphere

The biosphere is an interacting zone between lithosphere, atmosphere hydrosphere. It extends 10,000 metres in height in atmosphere, 11,034 metres in depth in oceans and only about 250 metres deep into the lithosphere. In the biosphere life forms are divided into two categories:

(i) Plant Kingdom

 (ii) Animal Kingdom


In each kingdom there are many different species of forms of life. Only man belongs to a single species of homosapiens Species.


Biosphere- Importance of Plants and Animals:

Man is an indispensable part of biosphere. His existence, origin and progress is also linked to the progress of biosphere. Even today man depends on biosphere to fulfil many of his needs. The human civilisation is not possible without the existence biosphere. We can not even think of human existence without biosphere being in healthy condition. The following points state the importance of biosphere.

(1) Food:Man derives his food from plants and animals. Most of the food grains like wheat, rice, pulses like arhar, oils and vegetables including fish and other animals whose flesh man eats have been found on earth because of the biosphere. Man selected many plants from the biosphere and started cultivating them and is still continuing for the continuous supply of his food. With the passage of time new plants are added to it. It is why man has also domesticated some of the animals for milk and meat.

(2) Clothes:Man is dependent on biosphere for needs of clothes to cover his body. Even the synthetic clothes are made available to us by virtue of certain naturally growing plant substances like for example cellulose. The fibers like cotton, jute, wool, and silk are all derived from the biosphere.

(3) Drugs:The biosphere also makes possible many of the drugs and medicines used by us for cure and treatment of diseases. Many of the drugs are made from plant derivatives or fats and bones of animals.

(4) Housing:For the construction of houses we are completely dependent on biosphere not only because of wood but also cement, limestone and other construction materials which have been made naturally or from the remains of plants and animals.

(5) Paper:Many of the industrial raw materials come from biosphere. The best example is the pulp used for making paper and derived from plants. Similarly, other plant materials come from the biosphere.

(6) Industry:Many of the raw materials used by modern industries come from biosphere. Examples are cotton for textile industry, sugarcane for sugar industry, oilseeds for oil mills etc.


(7) Energy:Coal, petroleum and natural gas which are the only source of energy used for running power plants, vehicles and industries also come from biosphere. They are also derived from remains of tiny sea animals and plants.

(8) Tribals:Tribals are the people living in forests who follow their traditional modes of life that man lived in the past. They are even today found in great numbers all over the world particularly India. In Andaman and Nicobar groups of Islands, the Jarva tribe, who still live in forests, are the best example of how man is dependent on biosphere.

(9) All plants and animals are interdependent and in turn completely dependent on biosphere.

(10) Tourism and Entertainment:Forests, lakes, spots of scenic beauty are the means of entertainment for man. It has received great attention in modern times. The people come from far off places to visit tourist resorts to escape from heat and dust, pollution etc. in the cities. They even visit national parks, sanctuaries and other similar places for their entertainment.

(11) Transport:Man still uses animals like horse, ass, cattle, buffalo, camel and other animals to meet his transport needs in mountains or desert areas.

(12) Security:Even inspite of modern means of security, man is still making use of natural boundaries for his security. He also domesticates and trains dogs for his security needs and is thus dependent on biosphere.

(13) Soils:Soils are the basis of agriculture. Soils can not be made independently by man without biosphere.

In these and many other ways man is dependent on biosphere and will continue to be dependent on it in future as well.

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