What gives, you say? Isn’t human history a glorious ascent from rats to car salesmen to politicians and finally to humans? A linear progress in which ‘advance’ is by brain size and where stupid Neandertals were doomed to be out-competed by us?
Actually…no. That’s nineteenth century thinking, which mashed period free market principles into evolutionary theory. A misconception perpetuated by that trope of walking apes, deriving from the ‘March of Progress’ that Rudolf Zallinger drew for Time-Life books in 1965.
It’s good news for me. As someone of European descent, I apparently have up to 1.8 percent Neandertal genes. I always thought that explained why I spend up to 1.8 percent of my time swilling beer, belching, dropping wheelies in my car, and head-butting large concrete objects while grunting ‘ugh ugh, Thog bring mam-muth steak to wo-man.’ But if Neandertals were as smart as us, I guess I’ll have to find another explanation. Probably the Cro Magnon coming through, I suppose.
So how did this come about? Scientific thinking has moved past nineteenth century market philosophy. Paleo-anthropologists like Stephen J. Gould argue that evolution isn’t about ‘directional advance’, still less measured by the increasing size of a body part. It’s about change through time, which isn’t directional.
Current theory suggests the human template hasn’t changed since H. erectus appeared around 1.8 million years ago. This hominid, fossil evidence indicates, spread from Britain to Java, and isolated populations survived up to 140,000 years ago. Remains show that H. erectus was like us from the neck down ( ‘post-cranial morphology’), had command of fire and made tools. The archetypal fossil is KNM-WT15000, ‘Turkana Boy’, a 9-11 year old male who might have grown to 6’1″ had he lived to adulthood. A trove of H. erectus skulls recently discovered in Dmanisi, Georgia, suggests that contemporary species previously thought separate – H. antecessor, H.ergaster, even H. habilis – were actually H. erectus.
Studies indicate that about 700,000 years ago a new species, H. heidelbergensis, ‘Heidelberg Man’, diverged from H. erectus and also migrated out of Africa – probably a side effect of following favourable climatic zones. They had brains within the modern size range. The increase has been attributed, paleoanthropologists argue, to tool-making and reduction in jaw size that came about as a consequence of cooking. Later, theory goes, Heidelberg Man speciated into us – H. sapiens – in Africa, Neandertals in Africa and Europe, and Denisovans in Siberia. Neandertals had a bigger brain than ours, and were physically more than twice as strong. Trying to rank these species as ‘advances’ on each other is like saying lions are more advanced than tigers.
I’ve seen it argued that all represented different ways of being human.
According to the genetic record, Europeans have Neandertal genes because Neandertal men got frisky with Sapiens women in the Levant, 60,000 years ago. It was Neandertal men with Sapiens women because, if it was the other way around, the genes wouldn’t have been passed to our species. Genetic evidence suggests male progeny would have been sterile. Nor were Neandertals the only ones up for it. Recent genetic studies point to interbreeding between up to four close-related human species, back in the paleolithic.
This hasn’t reduced the genetic quirk about every modern human. Genetically, we are unusually close by biological standards. There is far less variation than has been observed in other primates. We are so close, in fact, that if we were dogs, we’d be the same breed. I prefer to think Labradors rather than those foo foo French things. The reason is that, around 75,000 years ago, we came very close to extinction – thus, we are all descended from a tiny and genetically homogenous group. Because Neandertals and Denisovans, genetically, were 99.5% identical to us, a small intrusion of their genes makes no difference.
I don’t know I’d want to meet a Neandertal. We were wimps – ‘gracile’. With upright foreheads and diminutive jaws, we’d have looked like children (‘neotony’). We were the geeky looking ones who would have got the atomic wedgies.
On the other hand, every other kind of human was wiped out by the deep cold and droughts of the last big glacial cycles. We weren’t. See what I mean when I trunk on in this blog about geeks winning?
Copyright © Matthew Wright 2014