COMPONENTS OF ENVIRONMENT,

ENVIRONMENT
                            The surroundings or conditions in which a person, animal, or plant lives is called environment.
                                                 Or
                       The aggregate of social and cultural conditions that influence the life of an individual or community
                                                  Or
                      Thecomplex of social and cultural conditions affecting the nature of an individual or community.
                                                 Or
                     The combination of external physical conditions that affect and influence the growth development and survival of organisms is called environment.

COMPONENTS OF ENVIRONMENT
               The term Environment  can be broadly defined as one’s surroundings. To be more specific we can say that it is the physical and biological habitat that surrounds us, which can be felt by our physical faculties (seen, heard, touched, smelled and tasted.)
    The two major components of environment are :
(A) Non living or physical component:  This include non living things like Air, Water, and Land etc. This is also called the Abiotic component.
(B) Living component: All living organisms around us including plants, animals, and microorganisms. This is also called the Biotic component.
 Generally we classify environment into four segments :
(1) Lithosphere
(2) Hydrosphere
(3) Atmosphere
(4) Biosphere.
         The first three are non living while the fourth one is living.


LITHOSPHERE
           The earth’s crust consisting of the soil and rocks is the lithosphere. The soil is made up of inorganic and organic matter and water.

HYDROSPHERE
           This comprises all water resources both surface and ground water. The world’s water is found in oceans and seas, lakes and reservoirs, rivers and streams, glaciers and snowcaps. The distribution of water among these resources is as under.
Oceans and Seas 96–97 %
Glaciers and polar icecaps 2–3 %
Fresh water < 1%

BIOSPHERE
           The biosphere is a capsule encircling the earth’s surface where in all the living things exist. This portion extends from 10000 m below sea level to 6000 m above sea level. Life forms do not exist outside this zone. The biosphere covers parts of other segments of the environment like Lithosphere, Hydrosphere and Atmosphere.

ATMOSPHERE
           It is the gaseous envelope surrounding the earth. The composition of the atmosphere is given below.
Nitrogen 78.1%
Oxygen 20.9 %
Water vapour  0.1–5 %
Argon 0.9 %
Carbon dioxide 0.03 % etc
           The atmosphere, which is a gaseous cover, protects the earth from cosmic radiations and provides life sustaining Oxygen, the macronutrient Nitrogen and Carbon dioxide needed for photosynthesis. The atmosphere screens the dangerous UV radiations from the sun. The atmosphere plays a major role in maintaining the heat balance of the earth by absorbing the re emitted radiation from the earth. In addition the atmosphere is the medium of carriage of water from the oceans to the land in the hydrological cycle.