Discovery of 300, 000 year old fossils challenges timeline of human evolution
PREVIOUSLY IT WAS BELIEVED that modern humans emerged in East Africa 200, 000 years ago, however a new discovery has revealed that the process of human evolution is far more complex than we’d initially thought.
The discovery of 300, 000 year old human remains in Morocco demonstrates that the evolution of homo sapiens occurred 100 00 years earlier than previously believed. This also suggests that this evolution occurred widely across the African continent.
The Australian geochronologists analysed 22 bone fossils from Jebel Irhoud in Morocco. Two dating techniques were used — Uranium series and electron spin resonance
Head researcher Jean-Jacques Hublin told the Guardian, “This gives us a completely different picture of the evolution of our species. It goes much further back in time, but also the very process of evolution is different to what we thought.”
It looks like our species was already present probably all over Africa by 300, 000 years ago. If there was a Garden of Eden, it might have been the size of the continent,” he added.
Some of the Middle Stone Age stone tools from Jebel Irhoud (Morocco). Pointed forms such as a-i are common in the assemblage. Also characteristic are the Levellois prepared core flake(Image Credit Mohammed Kamal)
Two Australian dating experts, Rainer Grün from Griffith University and Renaud Joannes-Boyau from Southern Cross University, helped analyse the skulls, bones and teeth of five individuals, to determine the age of the fossils.
Australian Geographic spoke with Rainer about his analysis.
“It gives you insights into how fast the morphology of humans changed. Now you have fossils that are 300, 000 years old and you have fossils that are 200, 000 years old, some that are 160, 000 years old. We can now construct how fast morphological changes occur in the lineage of modern humans,” said Rainer, adding, “You get an idea about the timing of the occurrence of various features of modern humans.”
Much of Rainer’s work focuses on dating techniques that ensure minimal damage of the fossils.
“My research is not directly related to reconstructing human evolution, my research is more directed to be able to miniturise dating,” said Rainer.
“This is where the amount of fossil material used is minimised. Originally if you wanted to date teeth, a whole tooth would disappear. We’d have to grind it up and we have to take quite large samples for Uranium series dating. I improved it so I could just cut a tooth in half and do most of the analysis on the inside. Before this, I never got any human teeth because curators would simply say no.”
Virtual palaeoanthropology is able to correct distortions and fragmentations of fossil specimens. This reconstruction of the Irhoud 11 mandible allows its comparison with archaic hominins, such as Neandertals, as well as with early forms of anatomically modern Humans (Image Credit: Sarah Freidline)
The research was originally published in the journal Nature.