Broadly we can divide the environment into four spheres atmosphere, lithosphere, hydrosphere and biosphere.
1. Atmosphere: The atmosphere is the thin layer of air that envelops our earth. It is very dynamic in nature, changes can take place every hour. These changes in the atmosphere produce weather and climate. The atmosphere is not uniform all through its width. There are several layers of the atmosphere. The atmosphere provides a setting in which all forms of life are created and sustained. The force of gravity exerted by the earth holds the atmosphere around it. The atmosphere protects us from scorching heat and harmful ultraviolet radiation.
2. Lithosphere: The lithosphere is the layer of the earth consisting of rock materials, extending both over the continents and ocean basins. The overage thickness of the lithosphere is about 100 km.
- The lithosphere is composed of oceans and continents. It has two parts—Sial and Sima.
- The lithosphere is the sphere which provides us land to settle, soils for plants and is a source of mineral wealth.
Four Spheres of The Earth
3. Hydrosphere: The hydrosphere is the part of the earth’s surface, covered by water. Rivers, lakes, seas, and oceans form this sphere. More than 70 percent of the earth’s surface is covered with water. Continents are like vast islands floating in the oceans. On the other hand, oceans are the major link between landmasses. Water supports all forms of life on the earth and is very crucial for our survival. Oceans provide us with food and minerals. Even in the sea-bed, deposits of minerals, oil, and gas are found.
4. Biosphere: The biosphere is a very narrow sphere of the earth that contains life. This sphere includes parts of the atmosphere, hydrosphere, and lithosphere. Most of the living organisms are it plants or animals on the earth are found on or near the surface of land or water surrounded by air. Thus the biosphere is a very narrow zone where life on this planet exists.
