ENVIRONMENTAL STUDIES(ES)

Biosphere

ENVIRONMENTAL STUDIES

Lesson 8: Ecosystems

Lithosphere

The soil and rocks on the earth’s surface as well as below water form the solid component, called lithosphere. The lithosphere began as a hot ball of matter which formed the earth about 4.6 billion years ago. Of the 92 elements in the lithosphere, only eight are common constituents of crystal rocks. Of these constituents – 47% is oxygen, 28% is silicon, 8 % is aluminum and 5 % is iron, while sodium, magnesium, potassium\m and calcium constitute 4% each. Rocks, when broken downs, form soil on which man is dependent for agriculture.