Our ancestors started banging rocks together somewhere in east Africa several million years ago. Then came Homo. Smart, competitive and bent on domination, they wiped out other species, including our Neanderthal brethren until there was just one survivor of the hominid lineage; us. Explains a lot, right?
Wrong. That’s the traditional story, but new research is rewriting pretty much every chapter of human evolution, from start to finish and even beyond. Here are five of the latest theories that are helping us repaint the picture of who we are, how we got here, and where we’re going:
1. We came from the West
West? I thought it was all about the Rift Valley and Lake Turkana in east Africa? Well, the recent discovery of some seven million year old hominid fossils in northern Chad’s Djurab Desert has not only extended our fossil record by two million years, but also raises the possibility that hominids emerged not in east Africa, but further west.
2. The cognitive divide is shrinking
Brutish, monosyllabic and easy to outsmart, the picture we paint of our Neanderthal brethren is hardly flattering. But now, study after study suggests Neanderthals were pretty much as smart as we are. From the discovery of more avant-garde equipment, like a leather-burnishing tool, to evidence that they decorated their bodies with paint, jewellery and even feathers, there’s plenty to suggest that Neanderthals were not only technologically sophisticated, but culturally too; they had symbolic traditions just like us.
3. We benefited from sex with other human species
So Eurasian populations are up to 3% Neanderthal? Well, far from explaining the existence of louts and hooligans, turns out their genes did us some good. New studies show they gave us some really important immunity genes. And we didn’t just get jiggy with Neanderthals. Apparently some of our newly arrived ancestors took a shine to the Denisovans – a recently discovered population living in Siberia about 40,000 years ago. Sex with them benefited us too – a Denisovan gene has recently been shown to help Tibetans live at higher altitudes.
4. Survival of the nicest?
The traditional telling of human evolution is one of competition, individual selection and dominance, of the ‘selfish gene’ and survival of the fittest. But does this really explain why our species flourished?
These days, researchers are paying much more attention to the idea that we owe our lives more to our ancestors’ capacity to cooperate than we do to their capacity for violence, and these tendencies have much deeper evolutionary roots than previously thought.
Primatologists have observed that among our primate cousins, dominant chimps are the most generous. Even when facing strangers, capuchins and bonobos have been seen to interact by sharing food and exchanging favours with outsiders. Cooperation with strangers is simply an extension of cooperation with non-family members.
Geneticists too are increasingly looking at selective pressures not as acting on the individual gene, or even an individual’s genome, but on the genetic material of entire groups. Death to the selfish gene, vive the social genome!
5. We are still evolving
Our technological advancement has made us exempt from natural selection. There is no ‘survival of the fittest’ if everyone lives to old age. Human evolution is over, our beloved (but mistaken) David Attenborough once declared.
New evidence suggests that rather than coming to a standstill, human evolution is, if anything, accelerating. Straight black hair, blue eyes and lactose tolerance in adults are all examples of traits that have only become widespread in the last 30,000 years. And with larger populations, more reproduction and a higher chance of new advantageous mutations, evolution looks set to continue rapidly – as Frans de Waal has said, the way genes interact means that instead of becoming a world of latte coloured clones, we are starting to see a glorious riot of variation.
So, our family tree is bushier and more tangled than ever before and cooperation, rather than competition, is being recognised as the fundamental factor of our success. The picture of human evolution, of who we are and how we got here, is changing. For the better.
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