INTRODUCTION

INTRODUCTION

As you have read in the first chapter, the earth is the only planet that has life. Human beings can live here because the life-sustaining elements of land, water, and air are present on the earth.

The surface of the earth is a complex zone in which three main components of the environment meet, overlap, and interact. The solid portion of the earth on which we live is called the Lithosphere. The gaseous layers that surround the earth, is the Atmosphere, where oxygen, nitrogen, carbon dioxide, and other gases are found. Water covers a very big area of the earth’s surface and this area is called the Hydrosphere. The Hydrosphere comprises water in all its forms, that is, ice, water, and water vapor.

Word Origin

In the Greek language, Lithos means Stone; Atmos means Vapour; Hudor means Water; and Bios means Life.

Can you make words using the above?

Source: This Topic is taken from NCERT TEXTBOOK.

BIOSPHERE – THE DOMAIN OF LIFE

BIOSPHERE – THE DOMAIN OF LIFE

The Biosphere is the narrow zone where we find land, water, and air together, which contains all forms of life.

(Or)

The biosphere is the narrow zone of contact between the land, water, and air.

It is in this zone that life, that is unique to this planet, exists. There are several species of organisms that vary in size from microbes and bacteria to huge mammals. All the living organisms including humans are linked to each other and to the biosphere for survival.

The organisms in the biosphere may broadly be divided into the plant kingdom and the animal kingdom. The three domains of the earth interact with each other and affect each other in some way or the other. For example, cutting forests for fulfilling our needs of wood, or clearing land for agriculture may lead to the fast removal of soil from slopes. Similarly, the earth’s surface may be changed due to natural calamities like earthquakes. For example, there could be a submergence of land, as happened in the case of a Tsunami recently. Parts of the Andaman & Nicobar Islands were submerged underwater. Discharge of waste material into lakes and rivers makes the water unsuitable for human use. It also damages other forms of life.

Emission from industries, thermal power plants, and vehicles, pollute the air. Carbon dioxide (CO₂) is an important constituent of air. But an increase in the amount of CO₂ leads to an increase in global temperatures. This is termed as global warming.

There is thus, a need to limit the use of resources of the earth to maintain the balance of nature between the domains of the lithosphere, the atmosphere, and the hydrosphere.

Source: This Topic is taken from NCERT TEXTBOOK