Major Domains of the Earth
Lithosphere is derived from the Greek word “lithos”, meaning ‘rock’. This is rigid, rocky upper layer of the Earth. Lithosphere is split into seven continents. They are Asia, Europe, Africa, North America, South America, Australia, and Antarctica.
There are five major oceans in the world. They are Pacific Ocean, Atlantic Ocean, Indian Ocean, Arctic Ocean, and Southern Ocean.
Southern Ocean is the world's newest and fourth-largest ocean. In 2000, the International Hydrographic Organization decided to delimit a fifth ocean. It extends from the coast of Antarctica to 60 degrees south latitude. It has a total area of 20,327,000 sq km.
More than 71% of the earth’s surface is covered with water. A small percentage is available as fresh water for human use.
The envelope of gases surrounding the earth is called atmosphere. It is a mixture of nitrogen (78%), oxygen (21%), and other gases (1%). There are five major layers of Atmosphere. These are Troposphere, Stratosphere, Mesosphere, Ionosphere, and Exosphere. Atmosphere is a mixture of dust particles, gases and water vapours.
Biosphere is the part of the earth's crust, waters, and atmosphere that supports life. Organisms in the biosphere are broadly divided into plants kingdom and animal kingdom. Discharge of waste material into lakes and rivers makes the water unsuitable for human use. Cutting of forests for fulfilling our needs of wood, or clearing land for agriculture may lead to fast removal of soil from slopes. Similarly earth’s surface may be changed due to natural calamities like earthquakes.