Page 115 - SST Class 07

Overall, the hydrosphere is very large, with the This helps them to live and grow. They also release
oceans alone covering about 71% of the surface oxygen in the air which all lifeforms on the earth
area of the earth. need to breathe for their survival. From this descrip-

The motion of the hydrosphere and the tion, you might have observed that there is a con-
exchange of water between the hydrosphere and stant interaction between lithosphere on which
plants grow, atmosphere which supplies carbon
cryosphere is the basis of the hydrologic cycle.
dioxide and hydrosphere which is the source of water
The continuous movement and exchange of
vapour form in the air. This is not the only process,
water helps to form currents that move warm
but there are similar other processes which are a
water from the tropics to the poles and help
product of this interaction and interdependence.
regulate the temperature of the earth. The
exchanging of water is thus a vital part of the Biosphere
hydrosphere. The environment link on the earth between its
Atmosphere three spheres – lithosphere, hydrosphere and
We live at the bottom of an invisible ocean called atmosphere, is explained by the biosphere. This
the atmosphere, a layer of gases surrounding our sphere includes parts of these three spheres. In
planet. Nitrogen and oxygen account for 99 other parts, there is no life. For example, beyond
percent of the gases in dry air, with argon, carbon a certain height of the atmosphere from the
surface of the earth, life cannot survive. Similarly,
dioxide, helium, neon and other gases making up
in ocean depths where sunlight cannot penetrate,
minute portions. Water vapor and dust are also
very few forms of life exist. Similarly, the living
part of the earth’s atmosphere. Other planets and
organisms on the earth are found where water
moons have very different atmospheres and
some have no atmosphere at all. and air exist.
The atmosphere is so spread out that we barely Life on the earth is, however, influenced by a
notice it, yet its weight is equal to a layer of water combination of other factors and features like
more than 10 meters (34 feet) deep covering the landforms, climate, intensity of sunlight and slope
entire planet. The bottom 30 kilometers (19 of the land.
miles) of the atmosphere contains about 98
Atmosphere
percent of its mass. The atmosphere—air—is
much thinner at high altitudes. There is no
atmosphere in space.

Interaction and interdependence of the realms of
the earth

There is no rigid pattern for interaction and interde-
pendence of the realms of the earth. It is also not an
imaginary idea or guess. This interaction and interde- Biosphere
Hydrosphere
pendence is visible to us on the earth in many forms.
For example, photosynthesis which you have been
studying since primary classes. Through this process Lithosphere
plants convert atmospheric carbon dioxide and water
to form nutrients in the presence of sunlight. The four Components of Biophysical Environment
and the Interactions between Them.
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