The word environment is derived from the French word "Environ" meaning "Surroundings".Each and everything around us is called as environment. Every organisms is surrounded by materials and forces which constitute its environment, from which it must derive its needs.Environment creates favourable conditions for the existence and development of living organisms.
COMPONENTS OF THE ENVIRONMENT:
The environment consists of the following three important components.
1. Abiotic or Non-living component.
2. Biotic or Living component.
3. Energy component.
1. Abiotic (or) Non-living Component (or) Physical Component:
The non-living components of the environment are called abiotic components.
Eg: Air, Water, Soil and minerals.
These abiotic components enter the body of living organisms directly or indirectly, take part in metabolic activities and then return to the environment.
Abiotic components are subdivided into three categories:
1.Atmosphere :
The cover of air, that envelopes the earth is known as the atmosphere.The atmosphere extends upto 500 kms from the earth surface.The atmosphere is essential for all living organisms. It comprises 78% of nitrogen, 21% of oxygen and 1% of other gases.
Structure of atmosphere:
Structure of atmosphere can be classified into the following three types.
(a) Troposphere (10-18 kms):
It contains 75% of the atmosphere air mass. It also contains moisture.
(b) Stratosphere (18-50 kms):
It is rich in ozone gas and free from moisture and clouds. It prevents the UV radiation from the sun.
(c) Mesosphere (50-85 kms):
It contains less ozone but more nitrogen oxide.
Functions of atmosphere:
The aqueous envelope of the earth (i.e, 75% of the earth surface) is called hydrosphere.Oceans, lakes,rivers and water vapour constitute hydrosphere. About 97% of earth's water is in oceans, which is too salty and not fit for drinking.Only 3% is available as fresh water.
The living components of the environment are called biotic components.
COMPONENTS OF THE ENVIRONMENT:
The environment consists of the following three important components.
1. Abiotic or Non-living component.
2. Biotic or Living component.
3. Energy component.
1. Abiotic (or) Non-living Component (or) Physical Component:
The non-living components of the environment are called abiotic components.
Eg: Air, Water, Soil and minerals.
These abiotic components enter the body of living organisms directly or indirectly, take part in metabolic activities and then return to the environment.
Abiotic components are subdivided into three categories:
- Atmosphere
- Lithosphere
- Hydrosphere
1.Atmosphere :
The cover of air, that envelopes the earth is known as the atmosphere.The atmosphere extends upto 500 kms from the earth surface.The atmosphere is essential for all living organisms. It comprises 78% of nitrogen, 21% of oxygen and 1% of other gases.
Structure of atmosphere:
Structure of atmosphere can be classified into the following three types.
(a) Troposphere (10-18 kms):It contains 75% of the atmosphere air mass. It also contains moisture.
(b) Stratosphere (18-50 kms):
It is rich in ozone gas and free from moisture and clouds. It prevents the UV radiation from the sun.
(c) Mesosphere (50-85 kms):
It contains less ozone but more nitrogen oxide.
Functions of atmosphere:
- It maintains the heat balance on the earth by absorbing the IR radiations.
- The gaseous constituents play an important role in sustaining life on earth.
Carbon-di-oxide is essential for photosynthesis activity of plants.
Nitrogen is an essential nutrient for plant growth.
2.Lithosphere:
The soil and rock components of the earth is called lithosphere.
Functions of Lithosphere:
- It is a home for human beings and wildife.
- It is a store house of minerals and organic matters.
The aqueous envelope of the earth (i.e, 75% of the earth surface) is called hydrosphere.Oceans, lakes,rivers and water vapour constitute hydrosphere. About 97% of earth's water is in oceans, which is too salty and not fit for drinking.Only 3% is available as fresh water.
Functions of hydrosphere:
- It is used for drinking purpose and also supports the aquatic life.
- It is also used for irrigation, power production, industries and transport.
The living components of the environment are called biotic components.
Eg: Animals, plants and micro organisms.
Biosphere :
The biological environment where the living organisms live and interact with physical environment (soil, water and air ) is called biosphere.
Functions of biosphere:
Plants through photosynthesis produce oxygen in the atmosphere.Animals inhale oxygen during respiration and give out carbon-di-oxide, which is again utilised by plants during photosynthesis.
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