MEANING OF THE ENVIRONMENT

The word Environment is derived from the French word “Environ” which

means “surrounding”. Our surrounding includes biotic factors like human beings,

Plants, animals, microbes, etc and abiotic factors such as light, air, water, soil, etc.

Environment is a complex of many variables, which surrounds man as well

as the living organisms. Environment includes water, air and land and the interrelation

ships which exist among and between water, air and land and human beings

and other living creatures such as plants, animals and micro organisms (Kalavathy,

2004).She suggested that environment consists of an inseparable whole system

constituted by physical, chemical, biological, social and cultural elements, which are

interlinked individually and collectively in myriad ways.

The natural environment consist of four interlinking systems namely, the

atmosphere, the hydrosphere, the lithosphere and the biosphere. These four systems

are in constant change and such changes are affected by human activities and vice

versa (Kumarasamy et al., 2004).

Components of Environment

Our environment has been classified into four major components:

1.Hydrosphere, 2.Lithosphere, 3.Atmosphere, 4.Biosphere.

Hydrosphere

Hydrosphere includes all water bodies such as lakes, ponds, rivers, streams

and ocean etc. Hydrosphere functions in a cyclic nature, which is termed as

hydrological cycle or water cycle.

Lithosphere

Lithosphere means the mantle of rocks constituting the earth’s crust. The

earth is a cold spherical solid planet of the solar system, which spins in its axis and

revolves around the sun at a certain constant distance .Lithosphere mainly, contains

soil, earth rocks, mountain etc. Lithosphere is divided into three layers-crusts,

mantle and core (outer and inner).

Atmosphere

The cover of the air, that envelopes the earth is known as the atmosphere.

Atmosphere is a thin layer which contains gases like oxygen, carbon dioxide etc. and

which protects the solid earth and human beings from the harmful radiations of the

sun. There are five concentric layers within the atmosphere, which can be

differentiated on the basis of temperature and each layer has its own characteristics.

These include the troposphere, the stratosphere, the mesosphere, the thermosphere

and the exosphere (Kalavathy, 2004).

Biosphere

It is otherwise known as the life layer, it refers to all organisms on the earth’s

surface and their interaction with water and air. It consists of plants, animals and

micro-organisms, ranging from the tiniest microscopic organism to the largest

whales in the sea. Biology is concerned with how millions of species of animals,

plants and other organisms grow, feed, move, reproduce and evolve over long

periods of time in different environments. Its subject matter is useful to other

sciences and professions that deal with life, such as agriculture, forestry and

medicine. The richness of biosphere depends upon a number of factors like rainfall,

temperature, geographical reference etc. Apart from the physical environmental

factors, the man made environment includes human groups, the material

infrastructures built by man, the production relationships and institutional systems

that he has devised. The social environment shows the way in which human

societies have organized themselves and how they function in order to satisfy their

needs (Kumarasamy et al., 2004).