In Search of Our Ancestors

      According to the most recent scientific and archaeological evidence, it appears that the earliest hominid biped (primate walking upright on two fee) to whom humans can trace their ancestry lived about 4 million years ago. By 1.7 million years ago, brain and body size, as well as other changes, were significant enough to suggest that the earlier primate named Australopithecus had been replaced by a new species, Homo erectus. By 1.2 million years ago, it appears that all hominids except Homo erectus had become extinct.
      Over the next 500 000 years, Homo erectus continued to evolve in the direction of modern humans, acquiring a larger brain and rounder skull but still with thicker skulls and brow ridges than we have today. By 400 000 years ago, the changes were again significant enough for Homo erectus to be reclassified as Homoe sapiens ("wise man").
      By 100 000 years ago, humans had settled in three distinct populations, all of which were Homo sapiens. In Europe and the Near East, there were people we call Homo sapiens neanderthalensis, or Neanderthals. Africa was populated by anatomically modern humans (Homo sapiens sapiens) and in Asia, there was another group of people for whom we still have too few fossils to make a clear definition. Sometime around 50 000 years go, the anatomically modern Africans began to invade Europe. Initially it was believed that the Neanderthals had evolved into Homo sapiens sapiens. But scientists are now quite certain that the invasion of Homo sapiens sapiens led to to the assimilation, if not extinction, of the Neanderthals. Eventually, Homo sapiens sapiens, our direct ancestors, inhabited all parts of the world, reaching Australia 40 000 years ago, the Americas 12 000 years ago, The Arctic 10 000 years ago, and the Pacific Islands a scant 2000 years ago.

Photo: http://humanorigins.si.edu/

Writing: ECHOES from the Past published by McGraw-Hill Ryerson Ltd.