Monday, August 24, 2009

Genes, Peoples and Languages

Genes, Peoples and Languages by Luigi Luca Cavalli-Sforza is an enthralling brief history of the current state of knowledge of human movement and original cultural development. Cavalli-Sforza endorses an interdisciplinary approach (genetic, anthropological, archaeological, linguistic), on the grounds that that increases the range of evidence and thus the reliability of conclusions. Apart from the flag-waving ‘racism is evil’ essay at the beginning (pp 3-8), including a comment about American racism which shows he doesn’t understand the US (p.7), a silly comment (p.177) about monarchies:
History shows that hereditary monarchies last only a short time …
(Cavalli-Sforza seems not to have noticed that of the three oldest institutions on the planet—the Papacy, the English Crown, the Japanese Throne—two are hereditary monarchies: hereditary monarchy actually has a much better track record of survival than democracy or republics) and an irritating factual lapse that puts the Ottoman failure before Vienna in the C18th rather than the C17th, he is very nicely matter of fact. His discussion of hybrid vigour is enough in itself to demolish much racist nonsense about race purity.

He is particularly good on the neolithic transition (‘revolution’ is a silly term for something that has taken millennia) from hunter-gatherer to farming existence. It is pretty clear that farming advanced by ‘demic diffusion’—i.e. from the spread of farmers. It took about 3,000 years to reach the far edge of Europe from the Middle East via Anatolia, advancing about 1 kilometre a year.

Hunter-gatherers have extremely low population growth rates – they have to carry everything, including children. Farmers on the other hand, despite living a less healthy existence (one reason why hunter-gatherers don’t immediately go ‘what a great idea!’), breed children as in-house labour force and old-age pension. Give them a chance and their population will grow rapidly. So farmers supplant hunter-gatherers (including a significant amount of intermarriage), a process that has been going on since agriculture was first developed 10,000 years ago. The European invasion of Australia was simply one of the final acts in the process. Though not the final one, as hunter-gatherers continue to be squeezed out in various rain forest areas. (So, the “neolithic transition” hasn’t yet finished.)

Agriculture itself was probably developed as a response to population pressure, since hunter-gathering requires very low population density – for most of human history, the population of farming New Guinea exceeded that of hunter-gatherer Australia.

I found the discussion of the evidence of the spread of the human species fascinating. Australia was settled by homo sapiens before Europe (homo sapiens entered Europe about 40,000 years ago, compared to 50-60,000 years ago for Australia). The original wave of Amerindians (maybe 35,000 years ago maybe 15,000 years ago) may have been as few as a dozen people. Europeans are, genetically, about one-third African and two-thirds Asian. Africa, as the original home of the species, is more genetically diverse than any other continent. The Basques are probably the remnant of the original paleolithic inhabitants of Europe.

There’s lots more, it’s a great and enlightening read.

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