The first hominids developed in Africa more than six million years ago, but modern humans have existed for approximately 200,000 years. They emerged in the Middle Paleolithic era, spreading from Africa to Europe and Asia.
Scientists have discovered a South African Australopithecus skeleton to be the oldest human-like form discovered as of 2014, although modern human skeletons from Middle Awash, Ethiopia and Kenya have been dated to be approximately 150,000 years old. To determine how old a population is, scientists look for high genetic diversity. Because some tribes in Central and East Africa have the greatest genetic diversity of all known populations in the world, they are considered the oldest populations.