The story of life and of man

A brief history of life, in millions of years ago (mya):

• The first cells appeared about 2000 mya. By 500 mya, invertebrates were active.
• Jawless fish appeared, then fish with stout, strong fins, the lobefins, which could move on land and back to water. They gave rise to the first amphibians. A lobefin called the Coelacanth, thought extinct, was caught in 1938 off South Africa.
• Amphibians gave rise to reptiles, which laid thick-shelled eggs that do not dry out on land. Reptiles ruled for millions of years; the dinosaurs were the most famous, and they disappeared suddenly about 65 mya.
• The first mammals were small, like shrews. They spread when the dinosaurs had gone.

The evolution of humans.

• About 15 mya, two primates lived: Dryopithecus, which was more ape-like, and Ramapithecus, which was more man-like. They were hairy and walked like gorillas and chimpanzees.
• About 3-4 mya, man-like primates walked upright in eastern Africa, standing about 4 feet tall.
• About 2 mya, Australopithecines lived in the grasslands of East Africa. They hunted with stone weapons and ate mainly fruit.
• Homo habilis, the first human-like being, had a brain of 650-800 cc and probably did not eat meat.
• Homo erectus, about 1.5 mya, had a larger brain, about 900 cc, and probably ate meat. Fossils were found in Java in 1891.
• Neanderthal man, with a brain of about 1400 cc, lived in the Near East and Central Asia between 100,000 and 40,000 years ago. They used hides to protect their bodies and buried their dead.
• Homo sapiens, modern humans, arose in Africa and spread across continents.

Then came culture. Cave paintings were made about 18,000 years ago; in India, they can be seen at the Bhimbetka rock shelter in Madhya Pradesh. Agriculture began about 10,000 years ago, and human settlements started.

Across this story, the trends are clear: larger brains, an upright walk, and the growth of tools, language and culture.