Components of environment

Environment in its true sense can be defined as all that
surrounds us. Environment is our basic life support system.
It provides the air we breathe, the water we drink, the food

Animals and a large variety of man-made things which
are necessary for our living. Thus, environment has both
natural and man-made elements. The natural environment
can be further bifurcated into two groups, i.e. the Physical
environment and the Biological environment. The Physical
environment includes all non-living things like land, water
and air. The Biological environment includes all living things,
such as plants and animals. Man is the most important component of the biological environment
who satisfies all the required needs from both parts (groups) of the environment.
The two components of the natural environment, that is the physical and the biological, are
largely interdependent and cannot be separated. Any major change in the physical environment is
bound to bring a change in the accompanying biological environment. The change can be sudden or
gradual. For example, the development of soil takes years together and cannot be visualised through
our senses. On the other hand, some changes are very sudden, like the changes brought about by
the occurrence of an earthquake or volcano, etc.

FOUR SPHERES OF ENVIRONMENT-

The natural environment can be broadly divided
into four spheres, i.e. Lithosphere, Atmosphere,
Hydrosphere and Biosphere. Each of these is unique
in its own way and supports others in sustaining life
forms on our planet called the Mother Earth. Let us
understand the importance of each sphere of the
natural environment.

Lithosphere-

The literal meaning of ‘lithosphere’ is the ‘sphere
of rocks’. The earth’s solid layer is called lithosphere.
The lithosphere is about 100 km in thickness. The uppermost part of the lithosphere is composed of
rocks rich in silica and aluminium called sial. Below the sial layer, the rocks are mainly rich in silica
and magnesium and are called sima, which is generally found below the bottom of the ocean basins.
Thus, lithosphere is that part of the earth which provides us land over which we live. It provides
soil for the plants and is also a source of all the mineral wealth.

Atmosphere-

The literal meaning of ‘atmosphere’ is the ‘sphere of air’. The atmosphere is composed of a
mixture of gases which forms an envelope around the earth. It is a gaseous envelope extending
about 1,600 km above the earth’s surface. Of the total mass of the atmosphere, 99 per cent exists
within 32 km of height from the earth’s surface.
Among the four major elements of environment, atmosphere is the most dynamic in nature
where changes occur not only from one season to another but also within a short period of time say,
a few hours. These sudden changes produce changes in atmospheric conditions which affect our life
both directly and indirectly.

Hydrosphere-


Hydrosphere refers to the ‘sphere of water’ which
is present in oceans, rivers, lakes and other water
bodies on the earth’s surface. The planet earth is
often called the Water Planet or the Blue Planet
because of abundance of water on its surface. The
water bodies that include rivers, lakes, seas and
oceans cover 71 per cent of the earth’s surface.
The distribution of water is not uniform in both
the Northern and the Southern Hemispheres. It is
estimated that 43 per cent of the total area covered
by water lies in the Northern Hemisphere whereas the remaining 53 per cent lies in the Southern
Hemisphere. Oceans hold 96.5 per cent water on the earth. Rest of the water is available in the form
of ice, water vapours, underground water, rivers and lakes.

Biosphere-

The word ‘biosphere’ literally means the ‘sphere of life’.
Biosphere is the narrow zone of contact between all the three
spheres of environment where all kinds of life exist.
Most of the living organisms like plants, animals and microbes     

present on the earth are found on or near the earth’s surface of
the land, water and air. Human beings are an important part of the
biosphere. They are capable of changing it.
The earth is full of diversities. There is diversity in land, soil, plants and animals. This process
of diversification has occurred largely over long period of time resulting in the emergence of new
species of plants and animals. These changes create biodiversity on the earth.
The Government of India has passed the Wildlife Protection Act in 1972 to protect and conserve
this biodiversity. Under this Act poaching and hunting are prohibited. Violation of this Act is a
punishable crime under law. It is not only the duty of the government to protect and preserve
wildlife but all of us are responsible.

Human beings, as an important part of the environment, are well-equipped to exploit, consume
or utilise different plant and animal species existing on the earth’s surface. It is the need of the
present times that we should live in harmony with our surroundings. This will allow the earth to
sustain all forms of life on it and to produce newer ones in the course of time.

Keywords
• biodiversity: it is a variety of life on earth comprising of plants, animals and micro-organisms.
• microbes: very small organisms.
• national park: a well demarcated reserved area for the protection of wildlife. It does not allow any
human activity.
• ocean: vast expense of saline water on the earth’s surface.
• wildlife sanctuary: a geographical area meant for the conservation of biodiversity. Limited human
activities are permitted.
Do You Know?
Some critically endangered species of animals in India are Forest Owlet, Ganges Shark, Tiger Toad,
Flying Frog, Leatherback Turtle, etc. Presently, there are 102 National Parks and 515 Wildlife
Sanctuaries in India.