2. Mammals make up just 5,416 of the two million identified species on Earth
3. The theory of evolution, which explains how living things change over time through natural selection, was first publicized by Charles Darwin in 1859. Many scientists now point to this natural phenomenon as the reason behind Earth’s great biodiversity.
4. Apes originated on Earth about 35 million years ago, and the first apelike men appeared about 10 million years ago. The modern human species of Homo sapien has existed on the earth for only 100,000 years.
5. DNA was first discovered in 1869 by Swiss physician Friedrich Miescher who noticed a microscopic substance in the pus on discarded bandages. The substance was later identified as DNA.
