HughPickens.com writes: Conventional wisdom states that mammalian diversity emerged from the ashes of the Cretaceous/Tertiary mass extinction event, ultimately giving rise to our own humble species. But Joshua A. Krisch writes at This Week that the asteroid that decimated the dinosaurs also wiped out roughly 93 percent of all mammalian species. "Because mammals did so well after the extinction, we have tended to assume that it didn't hit them as hard," says Nick Longrich. "However our analysis shows that the mammals were hit harder than most groups of animals, such as lizards, turtles, crocodilians, but they proved to be far more adaptable in the aftermath." Mammals survived, multiplied, and ultimately gave rise to human beings.
So what was the great secret that our possum-like ancestors knew that dinosaurs did not? One answer is that early mammals were small enough to survive on insects and dying plants, while large dinosaurs and reptiles required a vast diet of leafy greens and healthy prey that simply weren't available in the lean years, post-impact. So brontosauruses starved to death while prehistoric possums filled their far smaller and less discerning bellies. "Even if large herbivorous dinosaurs had managed to survive the initial meteor strike, they would have had nothing to eat," says Russ Graham, "because most of the earth's above-ground plant material had been destroyed." Other studies have suggested that mammals survived by burrowing underground or living near the water, where they would have been somewhat shielded from the intense heatwaves, post-impact. Studies also suggest that mammals may have been better spread-out around the globe, and so had the freedom to recover independently and evolve with greater diversity. "After this extinction event, there was an explosion of diversity, and it was driven by having different evolutionary experiments going on simultaneously in different locations," Longrich says. "This may have helped drive the recovery. With so many different species evolving in different directions in different parts of the world, evolution was more likely to stumble across new evolutionary paths."
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