Evolution of Human Life
                         CONTINENTAL DRIFT
  In 1915, a German geologist and meteorologist, Alfred Wegener first
  proposed the theory of continental drift, which stated that parts of the
  Earth"s crust slowly drift atop a liquid core. The fossil record supports, and
  gives credence to the theories of continental drift and plate tectonics.
  Wegener hypothesized that there was a gigantic supercontinent 200
  million years ago, which he named Pangaea, meaning "All-earth".
  Pangaea started to break up into two smaller supercontinents, called
  Laurasia and Gondwanaland, during the Jurassic period. By the end of the
  Cretaceous period, the continents were separating into land masses that
  look like our modern-day continents. Wegener published this theory in his
  1915 book, On the Origin of Continents and Oceans.
Meaning of Prehistory The past of humanity began long ago. Most of it
went unrecorded and this unwritten past constitutes prehistory. But a small
fraction of the humanity’s past was recorded or written down, and it is this
written past that constitutes history. Prehistory has been divided into various
ages or periods on the basis of the nature of material remains of the past.
Radiation Theory An interesting theory holds that modern humans evolved
from Homo erectus, fairly recently, in Africa, and then peopled the Earth by
migrating along different routes.  This view is called the Radiation Theory and