Predicting risks of extinction

Brachiopods are marine shell fish that have hard "valves" (shells) on the upper and lower surfaces. The Ordovician is a geologic period and system, the second of six of the Paleozoic Era, and covers the time between 488.3±1.7 to 443.7±1.5 million years ago. Both are crucial to understanding a new study from Franklin scientists:

A team of scientists analyzed more than 46,000 fossils from 52 sites and found that greater numbers did indeed help clam-like brachiopods survive the Ordovician extinction, which killed off approximately half of the Earth's life forms some 444 million years ago. Surprisingly, abundance did not help brachiopod species persist for extended periods outside of the extinction event.

Study co-author Steven Holland, a professor of geology in the UGA Franklin College of Arts and Sciences, said the seemingly paradoxical finding suggests that predicting which species are at risk of extinction is an extremely dicey endeavor.

"This study shows that extinction is much more complicated than generally realized," said Holland, whose findings appear in the current issue of the journal Paleobiology. "It turns out that a lot of extinction events are idiosyncratic; there are a specific set of circumstances that come together and dictate whether something goes or doesn't."

This new work will likely receive a great amount of attention, and rightly so. Geological and paleobiological studies branch out in so many directions, they are a literally endless route of investigation. Congratulations to these scientist for their contributions in illucidating new theories on complex, if widely held, views of phenomena that connect us with our past - and that hopeful guide our future.

Image: fossil brachiopods, University of Georgia.