Environment is a combination of both biological as
well as physical elements which can directly or indirectly affect the
development, growth rate, reproduction rates, survival and size of population
of an organism living in the given set of conditions of that environment. The main
fundamental physical elements of which the environment is made up are water,
land and air. The environment is comprised of four basic segments which are
given as follows
1. Lithosphere
2. Hydrosphere
3. Atmosphere
4.
Biosphere
1. Lithosphere:
The earth crust or land is comprised of rocks and
soil which is called solid segment of the environment named as lithosphere. All
the metals lie beneath the layers of this segment of the environment. There are
three layers of lithosphere named as
a)
Inner
and outer core of the earth
This
layer of lithosphere is comprised of central fluid of earth and it lies about
twenty five hundred kilometers (2500 km) from the center of the earth.
b)
Mantle
This
layer consists of molten phase and lies about twenty nine hundred kilometers (2900
km) above the core of the earth.
c)
Crust
It
is the outer most and solid part of the earth comprises of soil and rocks. It lies
about forty kilometers (40 km) above the mantle of the earth.
2. Hydrosphere:
This segment of the environment comprises of liquid
phase of the earth in the form of water including all the water bodies like
oceans, rivers, lakes and ponds. Hydrosphere covers about more than 70% of the
earth in which 97% area of hydrosphere consists of oceans, 2-3% water is
present in the form of glaciers and only 1% water is available in the form of
fresh water. Hydrosphere is the habitat for marine life. Marine life survives
only in the hydrosphere segment of the environment and cannot survive outside
this segment.
3. Atmosphere:
Blanket of air covering the earth is known as
atmosphere. It comprised of gas phase and serves as a protection shield for
earth that protects the life on earth from harsh outer space conditions. It also
provides oxygen for animals to survive and carbon dioxide for plants to live. The
height of this segment from earth’s surface is 1600 km.
4. Biosphere:
The region of aforementioned segments of the earth
where life exists including hydrosphere, atmosphere and lithosphere is
specifically called as biosphere. This zone is estimated from sea level and it
lies 6000 m above and 10000 m below sea level. This segment covers all forms of
life and no life exists outside this zone.
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