The earth is about 4.5 billion years old, but life did not exist on this planet until about 2 billion years ago, when certain kinds of bacteria and algae began to appear.
Land plants did not appear until about 430 million years ago; reptiles, 300 million years ago; and modern mammals, 75 million years ago. The first apes appeared about 35 million years ago, and the first apelike men, about 10 million years ago. Man, himself, has been on earth for only about 300,000 years.
If the 4.5 billion year history of the earth were to be measured in proportion to one year, man would not appear until Dec. 31, at 8:30 in the evening!
