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Tuesday, December 08, 2009

Human evolution: Now "the Hobbit" may revise "major tenets of human evolution"?

In "Rethinking 'Hobbits': What they mean for human evolution", we are advised by Scientific American (November 2009),
New analyses reveal the mini human species to be even stranger than previously thought and hint that major tenets of human evolution need revision.
Not only was H. floresiensis being held up as the first example of a human following the so-called island rule, but it also seemed to reverse a trend toward ever larger brain size over the course of human evolution. Furthermore, the same deposits in which the small-bodied, small-brained individuals were found also yielded stone tools for hunting and butchering animals, as well as remainders of fires for cooking them—rather advanced behaviors for a creature with a brain the size of a chimpanzee’s. And astonishingly, LB1 lived just 18,000 years ago—thousands of years after our other late-surviving relatives, the Neandertals and H. erectus, disappeared
More about the Hobbit (Flores man or homo Floriensis) controversy here.

It's never been clear to me that Flores man is a separate species. I think some people just need them to have been one, and they seize on anything that advances their case. Fortunately for them, no Florensians are alive today, so we can't answer the fundamental question of whether they could produce live, eventually fertile children with other humans.

Anyway, a friend writes to remind me that agnostic Australian philosopher David Stove, author of Darwinian Fairytales, pointed out some while ago:
If you discovered tomorrow a new and most un-Darwinian-looking species of animals, in which every adult pair produced on average a hundred offspring, but the father always killed all of them very young, except one which was chosen by some random process, it would take an armor-plated neo-Darwinian no more than two minutes to “prove” that this reproductive strategy, despite its superficially inadvisability, is actually the optimum one for that species. And what is more impressive still, he will be able to do the same thing again later, if it turns out that the species had been misdescribed at first, and that in fact the father always lets three of his hundred offspring live. In neo-Darwinianism's house there are many mansions: so many, indeed, that if a certain awkward fact will not fit into one mansion, there is sure to be another one into which it will fit to admiration.

—David Stove, collected essaysAgainst the Idols of the Age, p. 244,
It would be wisest to believe nothing and nobody about any of these speculations. All we know is, some intriguing skeletons were found, and the people they once belonged to lived pretty much as other humans did at the time, despite very small brains. Thus, human brain size is not well correlated with performance of basic hunter gatherer tasks. That in itself is not surprising. Check the brain absent stories here, for example. The human brain is very plastic.

Here's more on the Hobbit (Flores man).

Find out why there is an intelligent design controversy:

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