Mankind developed from ‘isolated groups’ in Africa
‘Garden of Eden’ idea challenged by skull-shape study
FOR years, experts believed humans evolved in a single “Garden of Eden” spot in Africa before spreading around the world, but now scientists say fossil records show there cannot have been just one area.
Instead, groups of early human species were dispersed across Africa in pockets. These communities, separated for millennia, developed diverse features in the shapes of their skulls and other bones. Over thousands of years, the groups sporadically interbred to create Homo sapiens.
Scientists say our species could not have developed from just one place, because evidence from skull shapes does not support this theory. If it were correct, skulls would have changed shape in a smooth “linear progression” over time.
However, the timeline is mixed: more recent skulls have primitive features and more ancient skulls, modern ones.
Professor Chris Stringer of the Natural History Museum and Dr Eleanor Scerri of Oxford University and colleagues put forward their case in the journal Trends in Ecology and Evolution. They said early humans were kept apart by diverse habitats and shifting environmental boundaries.
Many of Africa’s inhos- pitable regions, such as the Sahara, were once wet and green, with networks of lakes and rivers, and abundant wildlife. Similarly, some tropical regions that are humid and green today were once arid.
The shifting nature of the habitable zones meant groups of humans would have gone through many cycles of isolation, leading to the development of unique primitive technologies, such as stone tools, and highly diverse genes.
Stringer said: “The great diversity of African fossils between 200 000 and 400 000 years ago suggests that multiple lineages existed on the African continent at that time.”
Scerri said the stone tools discovered across Africa also didn’t show a clear progression from crude to sophisticated.
“The evolution of human populations in Africa was multi-regional. Our ancestry was multi-ethnic.”
Professor Mark Thomas of UCL added that it was “difficult to reconcile the genetic patterns we see in living Africans and in the DNA extracted from the bones of Africans who lived over the last 10 000 years, with there being one ancestral human population”. – Daily Mail
Professor Lee Berger of Wits University and Gauteng Premier David Makhura hold a replica of the skull of a possible human relative, Homo naledi, at the Maropeng Cradle of Humankind.