I have always been fascinated by the evolution of humans who for years experts believed originated 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, group 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 was correct, skulls would have changed shape in a smooth ‘linear progression’ over time. But the timeline is mixed – with more recent skulls having primitive features while more ancient skulls have modern features.
For example, older skulls dating back 300,000 years at Jebel Irhoud in Morocco have small faces like us. However, there braincase is elongated instead of spherical like a modern skull.
Earlier human fossils dating back 160,000 years ago from Ethiopia had big ‘robust’ faces quite unlike us, but with rounder braincases.
Professor Chris Stringer of the Natural History Museum and Doctor Eleanor Scerri of Oxford University and colleagues put forward their case in the journal Trends in Ecology and Evolution.
The author said early humans were kept apart by diverse habitats and shifting environmental boundaries such as forests and deserts. Many of the inhospitable regions in Africa today, such as the Sahara, where 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. This led to the development of unique primitive technologies such as stone tools and highly diverse genes.
Professor Stringer pioneered the Garden of Eden theory but now accepts this is wrong. He said ‘we do see a continental, wide trend towards the modern human form but some archaic features are present until remarkably recently.’
‘I have increasingly come to the realisation that our African origin was a complex process. The great diversity of African fossils between 200,000 and 400,000 years ago suggest that multiple lineages existed on the African continent at that time.’
Lead author Doctor Scarri said ‘the stone tools discovered across Africa don’t show a great progression to crude to sophisticated.’
She said ‘the evolution of human populations in Africa was multi-regional. Our ancestry was multi-ethnic and the evolution of our material culture was, multi-cultural.
Professor Mark Thomas of UCL added that the genetic patterns found also support their case.’ He said ‘it is difficult to reconcile the genetic patterns we see in living Africa and in the DNA extracted from the bones of African who lived over the last ten thousand years with their being one ancestral human population.’
For me, the mystery of the evolution of humans remains unbelievably complex. I always understood that most likely the Garden of Eden was situated somewhere in the Holy Land. But obviously scientists are more well versed in these matter than I could possibly be. All this however adds to my own fascination to the concept of creation overall.