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Re: mass extinction
At 10:35 AM +1000 3/21/06, Dann Pigdon dannj@alphalink.com.au wrote:
>I'd have thought that, given the rapid climate shift at the end of the
>Pleistocene, extinction rates would have been relatively swift then. Ice core
>studies suggest that the climate swung from glacial to interglacial within a
>human lifetime. That's a much greater change in global climate, within a much
>shorter time span, than us lowly humans have so far been able to manage.
>
Remember that the Pleistocene lasted over two million years, and during that
time the flora and fauna had evolved to survive a series of
glacial/interglacial cycles of varying duration. Successive ice ages did wipe
out evidence of previous glacial/interglacial cycles, but from what I've read
and investigated, there isn't much evidence of major megafaunal extinctions
during previous interglacial thaws. That's an important part of the evidence
that humans were linked to the Pleistocene extinction -- our widespread
presence was something that differed from prior interglacials.
--
Jeff Hecht, science & technology writer
jeff@jeffhecht.com http://www.jhecht.net