Major Domains Of 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 is called the Lithosphere.It comprises the rocks of the earth's crust and the thin layers of the soil that contain nutrient elements which sustain organisms.

There are two main divisions of the earth's surface.The large landmasses are known as the continents and the huge water bodies are called the ocean basins. All the oceans of the world are connected with one another.

Hydrosphere-The earth is called the blue planet.More than 71% of the earth is covered with water and 29% is with land.Hydrosphere consists of water in all its forms.More than 97% of the earth's water is found in the oceans and is too salty for human use.A large proportion of the rest of the water is in the form of icesheets and glaciers or under the ground water and a very small percentage is available as fresh water for humans.

The earth is surrounded by a layer of gas called the atmosphere.This thin blanket of air is an integral and important aspect of the planet.It provides us with the air we breathe and protects us from the harmful effects of sun's rays. The atmosphere extends up to a height of about 1600 kms.The atmosphere is divided into five layers b ased on composition,temperature and other properties.These layers starting from earth's surface are called the troposphere,stratosphere,mesosphere,thermosphere and exosphere.

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 organizms that vary in size from microbes an bacteria to huge mammals.All the living organisms including humans are linked to each other and to the biosphere for survival.