Over 65 million years North American mammal evolution has tracked with climate change

Brown University ^ | December 26, 2011

[decimon]

Rise and fall of groups of fauna driven by temperature

PROVIDENCE, R.I. -- History often seems to happen in waves – fashion and musical tastes turn over every decade and empires give way to new ones over centuries. A similar pattern characterizes the last 65 million years of natural history in North America, where a novel quantitative analysis has identified six distinct, consecutive waves of mammal species diversity, or "evolutionary faunas." What force of history determined the destiny of these groupings? The numbers say it was typically climate change.

"Although we've always known in a general way that mammals respond to climatic change over time, there has been controversy as to whether this can be demonstrated in a quantitative fashion," said Brown University evolutionary biology Professor Christine Janis. "We show that the rise and fall of these faunas is indeed correlated with climatic change – the rise or fall of global paleotemperatures – and also influenced by other more local perturbations such as immigration events."

Specifically, of the six waves of species diversity that Janis and her Spanish collaborators describe online this week in the Proceedings of the National Academy of Sciences, four show statistically significant correlations with major changes in temperature. The two transitions that show a weaker but still apparent correlation with the pattern correspond to periods when mammals from other continents happened to invade in large numbers, said Janis, who is the paper's senior and second author.

[gleeaikin]

I wish the article had included a graph showing the 6 episodes of climate/fauna change. I’ll bet one of them was around 34 million years ago. For that one there was definite cause: the great meteors in the Chesapeake and in Russia (Popogai sp?) which left 60 mile diameter craters and killed substantial numbers of animal groups.