Greater Species Turnover in Northern Climates?

More species develop in warm, tropical climates or cooler, temperate areas? It turns out the longtime answer — the tropics — may be wrong.

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New research suggests that is because tropical species do not die out as readily. Cooler regions have a higher turnover rate, with more species developing but also more becoming extinct.

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"It would take one species in the tropics 3 to 4 million years to evolve into two distinct species, whereas at 60 degrees latitude (two-thirds of the way toward either pole), it could take as little as 1 million years," Weir said.

"In other words, there's a higher turnover of species in places like Canada, making it a hotbed of speciation, not the Amazon," said Schluter.

That, however, is balanced by a higher extinction rate in colder climates, so the tropics still have more diversity.

It also raises the question of whether a more variable climate causes more rapid evolution.

Also interesting that in some of the mass extinction books I've read that there has been a lot of hints that the tropics are not as likely to have species get wiped as had been thought. I wonder if it was a case of thinking 'where we come from is best' (and then its flip side later) that colored the old beliefs.