One way to survive mass extinction.

One way to survive mass extinction 

Common wisdom among paleontologists holds that although plants and animals can adapt to their environments to avoid extinction in normal times, survival during mass extinctions --caused by floods, volcanoes or other catastrophes-- may be just a matter of luck. But now, Jennifer A. Kitchell, a University of Michigan at Ann Arbor paleontologist, has found evidence that adaptations made in normal times may help some organisms survive mass extinctions.

Kitchell studied various species of marine plankton, or diatoms, and found that those that had adapted to northern climates survived the mass extinction between the Cretaceous and Tertiary periods (65 million years ago), while plankton that had adapted to low- and mid-latitude sites did not. The diatoms in the north evolved a life cycle that includes a resting stage, which allows them to survive during the season of coldest water. Farther south, where ocean temperatures are more constant, plankton do not have a resting stage. The northern diatoms were able to survive the cold ocean temperatures of the late Cretaceous by entering their resting stage, Kitchell reports.

"I'm proposing that this adaptation was a fortuitous benefit,' Kitchell says. Her findings, she says, do not refute the argument that mass extinction is blind to adaptation, but they "qualify' it by suggesting that geographic range may be related to survival during catastrophic times.