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I have a burning need to know stuff and I love asking awkward questions.

Monday, February 07, 2011

Just Finished Reading: Human Evolution – A Very Short Introduction by Bernard Wood



I think that the thing that most surprised me about this book is the fact that, prior to the burying of our dead some 100,000 years ago, there have actually been very few discoveries of human fossils. At one point the author described how the total human fossil collection pre-dating 100KYA would easily fit into a shopping trolley. No wonder then that the full detail of our origins is largely missing and that arguments rage unresolved about which particular ancestor gave rise to recognisable Homo Sapiens.


Ideas of our origins are as old as human culture but it is only in the past 400 years or so, since the emergence of science, that we have actually been able to slowly piece together where we came from. With the framework provided by Darwin’s Evolutionary theories we are able to place humans on their correct taxonomic branch of the tree of life. With it we are able – as best we can – to place our evolutionary ancestors going back to the point where we spilt from the other apes and Great ape and arrive at the common ancestor of humans and chimpanzees some 5-8 Million years ago. Again I was surprised to discover that we know almost nothing about the evolution of chimpanzees – the only fossil evidence we have (at the time of the books publication) are 700,000 year old teeth from a site in Kenya. The evidence to the parting of the ways comes primarily from genetics rather than from the fossil record. This is something that I will definitely need to read more about. Of course the lack of fossils – for both early humans and chimpanzees is easy to account for. Before we buried our dead they would have been discovered by carrion eaters and scattered to the four winds. The very earliest bones were often discovered in caves – not because our ancestors lived there – but because scavengers took bones there to eat later. It is lucky that we have any fossils of early humans at all.


With so few fossils to examine it is hardly surprising that there is much debate as to whether these remains constitute different sub-species of humanity or if they simply represent natural variation within a species. It appears that at this stage we cannot know this with any certainty. Of course this leaves the actually evolutionary path of humans rather undefined. There is most definitely more work to be done here. What does seem certain though is the ‘Out of Africa’ hypothesis. It appears, from the evidence that we have so far, that humans first evolved in Africa and spread to the rest of the world from there in successive waves probably caused by climate change.


I found this book both fascinating and rather surprising. I had thought that we had a reasonable handle on our early evolution but this appears not to be the case. There is still much to discover and many debates to be settled. I definitely need to read up more about this and will attempt to do so in the coming year – so, as always, watch this space.

1 comment:

Stephen said...

It's very difficult to become a fossil, I think....one of history's most exclusive clubs. Fossils tend to clump together when there's an environment suitable for producing them. Since we humans haven't been around for very long, I imagine most human 'fossil' remains are regular old bones which have somehow escaped the passage of time and biological decay.

Did the author mention the various hoaxes, like Piltdown man? I just read a selection on human evolution myself (in "Galileo's Finger: the Ten Great Ideas of Scince")....there's a nice illustration of Neanderthals I man scan and post, but since they're nude I don't what Blogger's policy is. I doubt they'd take down a blog for posting the Vitruvian Man, and this amount of detail is similar...