New findings at a site in Morocco suggest that ‘pre-modern’ humans came to be at least 100,000 years earlier than thought, and evolved into modern humans after dispersing across all of Africa.
How and from where did modern humans evolve? Until now, the consensus was that it happened around 200,000 years ago in sub-Saharan Africa. However, results from a recently reopened excavation site in the Saharan nation of Morocco suggest that this probably was not the case.
The site of Jebel Irhoud was a hotbed of palaeo-anthropological studies in the 1960s and 1970s after some fossils relevant to human evolution were found there by accident. They were identified as those of our predecessors, who lived about 160,000 years ago. This is about 40,000 years earlier than when the modern humans, Homo sapiens, were supposed to have evolved.
In the past decade, interest in this site was renewed when a multinational team of scientists found more skeletal remains and stone tools as well. This time, the technology was more advanced. Luckily, the scientists noticed that the tools had been burnt at some point, probably while the people were cooking. This opened up the possibility of using one of the best dating techniques available – thermoluminescence – to estimate the time of burning. This would coincide with the rough age of these tools, and by extension the bones that were found in the same layer of the earth as them.
In this manner, the new fossils were dated to 300,000 years ago. An older fossil found in the 1960s was re-dated to show the same age. And the pieces of bones were reconstructed to reveal that these individuals were a lot more like today’s humans than has been thought. Though the shape of their braincases remained primitive, their faces had already begun to look identical to modern humans – so much so that the authors felt it fit to identify them as Homo sapiens. This declaration shook up the field of paleoanthropology like few discoveries could ever do.
These ‘pre-modern’ humans evolved at least 100,000 years earlier than thought, making them older than our cousins, the Neanderthals. Evidently, this evolution was happening simultaneously in many parts of Africa: not just in the sub-Saharan regions like Ethiopia but also in Morocco, presumably helped by climatic events at the time that gave rise to ‘green’ spots in the Sahara.
Scientists around the world have acknowledged the significance of the new studies, published in the journal Nature on June 7 (here and here). Some of them feel that the basis on which the fossils have been termed Homo sapiens is rather loose and are are wary of the hype. Nevertheless, the science media is abuzz with inspired coverages of this rewriting of history. This correspondent decided to throw some poetry into the mix.
Part I: The 1960 Find
There was once a bored barium miner,
Burning sun and dry throat, but he’s no whiner,
Then he spotted a skull,
Afternoon no more dull,
That night he was the star at the diner.
A professor who loved science and history,
Heard of the skull in a mine – what a mystery!
Called friends from abroad,
To visit Jebel Irhoud,
And tell the world about human ancestry…
Emile Ennouchi came from faraway France,
Here he found magnificent fossils that made him dance,
Of zebras and gazelle,
And as far as he could tell,
There were bones that looked like a human’s.
Near the bones lay stone tools in a scatter,
(In palaeontology, such things really matter),
They poked and they prodded,
Compared, gravely nodded,
One voice then emerged from the chatter…
These tools are rather Neanderthal-ish, so
These bones probably belonged to Neanderthals,
Who lived 40,000 years ago.
As years went by, more bones were found,
And science this time was lot more sound,
They weren’t Neanderthal (like thought before),
How old were they? 40,000 times four.
[The thing about paleoanthropology is
Discoveries are sometimes hit-and-a-miss]
Part II: Forty Years Later
In 2004, came along Jean-Jacques Hublin,
Who convinced Morocco to let him in,
And to his delight,
Hidden in the site,
More tools and bones looking quite human!
Experts of the world came to here to dwell
On these mysterious species, their story to tell,
Armed with a winning mix,
Of logic and science tricks,
The men and women all but did ‘Eureka!’ yell.
These beings were humans like us it seems,
Who lived in the Sahara, same place but more greens,
With faces like ours,
But longer brain covers,
300,000 years old. So you know what this means…
Twenty-first century science is pretty hardcore,
That means we can be (almost) sure,
That these enigmatic bones are from more
than three hundred thousand years before.