It is generally believed that human life originated on the continent of Africa. Many fossils of hominid species have been found in African countries.
Fossils of Australopithecus afarensis, living around three to four million years ago, have been discovered in Ethiopia
in the Lower Valley of the Awash. Remains of another early hominid, Australopithecus africanus, were found in South Africa
in caves in the Sterkfontein Valley. Fossils of Homo habilis, dated around two million years old, were unearthed in Tanzania
by the Leakey family at Olduvai Gorge.
There are a number of theories about the migration of humans from Africa. The Multi-regional theory says that groups of Homo erectus, who appeared over one and a half million years ago, migrated from Africa and evolved into modern humans in Asia and Europe, as well as Africa, around the same time. An opposing theory, known as Out-of-Africa, suggests that small numbers of modern humans, who lived in Africa one hundred and thirty thousand years ago and migrated around thirty to fifty thousand years later, eventually spread throughout the world and replaced earlier humans.
A later theory proposed by Professor Alan Templeton says that migration from the African continent took place in three waves. This theory suggests that modern Homo sapiens from Africa may have interbred with the archaic species living in Asia and Europe who had left Africa in earlier migrations.
The Out-of-Africa theorists believe that Homo neanderthalensis, a close evolutionary relative of modern humans, died out around thirty thousand years ago. It has been discovered that a group of Neaderthals, named after the Neander Valley in Germany
, lived in caves in Gibraltar
about this time or perhaps even later.
Fossils of Homo sapiens sapiens in Cro-Magnon in the Dordogne in France
show that some of our ancestors were living in Europe thirty-five thousand years ago.
Many people think that a small number of modern humans left Africa and moved into the Middle East around a hundred thousand years ago. Exact dates are difficult to assess and it has even been suggested that the move may have taken place only sixty thousand years ago. Migrating groups followed the coastline of Asia; some journeyed to Australia
, arriving between sixty thousand and forty thousand years ago. Eventually people moved into Central Asia and then into Europe. It is thought that the Americas were the last continents to be populated, possibly around twenty thousand years ago, perhaps via the Bering Strait land bridge.
The migrations took place over long periods of time. In some cases each generation may have moved on just a short distance
. In other cases longer journeys were undertaken such as the Polynesian migrations.