As reported by The Guardian, an international multidisciplinary team led by Oxford archaeologist Dr. Eleanor Scerri has claimed that a comprehensive survey of fossil, archaeological and genetic evidence shows humans “mosaic-like across different populations spanning the entire African continent”. Thus, modern humans did not come from a specific area — namely East Africa, where the oldest confirmed Homo Sapiens fossils have been found — but are the end result of millennia of interbreeding and cultural exchange between semi-isolated groups.
The telltale characteristics of a modern human – globular brain case, a chin, a more delicate brow and a small face – seem to first appear in different places at different times. Previously, this has either been explained as evidence of a single, large population trekking around the continent en masse or by dismissing certain fossils as side-branches of the modern human lineage that just happened to have developed certain anatomical similarities.
The latest analysis suggests that this patchwork emergence of human traits can be explained by the existence of multiple populations that were periodically separated for millennia by rivers, deserts, forests and mountains before coming into contact again due to shifts in the climate. “These barriers created migration and contact opportunities for groups that may previously have been separated, and later fluctuation might have meant populations that mixed for a short while became isolated again,” said Scerri.
The trend towards more sophisticated stone tools, jewellery and cooking implements also supports the theory, according to the paper in the journal Trends in Ecology & Evolution.
Scerri assembled a multidisciplinary group to examine the archaeological, fossil, genetic and climate data together, with the aim of eliminating biases and assumptions. Previously, she said, scientific objectivity had been clouded by fierce competition between research groups each wanting their own discoveries to be given a prominent place on a linear evolutionary ladder leading to the present day. Disputes between rival teams working in South Africa and east Africa had become entrenched, she said.
“Someone finds a skull somewhere and that’s the source of humanity. Someone finds some tools somewhere, that’s the source of humanity,” she said, describing the latest approach as: “‘Let’s be inclusive and construct a model based on all the data we have available.”
Like any study, the claims will need to be confirmed, but from my layman’s perspective, it makes sense. What are your thoughts? (Especially if you have a background in this area.)