An illustration showing Lystrosaurus during the end-Permian mass extinction. Credit: Gina Viglietti
SciTechDaily has a story about the Permian Mass Extinction. The worst mass extinction in Earth's history, the Permian Mass Extinction happened about 252 million years ago. Researchers at the Field Museum in Chicago looked at the rate of extinction on land to see if it matched what is seen in the oceans. They found the land extinctions took much more time... perhaps as much as ten times longer. The marine extinctions were 95% complete after 100,000 years, while life on land endured for about 1,000,000 years. Details can be found in a paper published in the journal Proceedings of the National Academy of Sciences.
“People assumed that because the marine extinction happened over a short period of time, life on land should have followed the same pattern, but we found that the marine extinction may actually be a punctuation to a longer, more drawn-out event on land,” says Pia Viglietti, a postdoctoral researcher at Chicago’s Field Museum and the lead author of the PNAS study.
“The focus for studying terrestrial extinction has basically been, ‘Can we match up the pattern in the terrestrial realm with what’s observed in oceans?’ And the answer is, ‘Not really,’” says Ken Angielczyk, the paper’s senior author and curator of vertebrate paleontology at the Field Museum. “This paper is the first really focusing on vertebrates and saying, ‘No, something was going on that was unique to the terrestrial realm.’”
Part of why scientists had looked to the marine extinctions for clues as to what happened on land is that there’s a more complete fossil record of life underwater. If you want to become a fossil, dying by water, where your body will rapidly get covered by sediment, is a good way to make that happen. As a result, paleontologists have known for a while that 252 million years ago a mass extinction hit at the end of the Permian period, and within 100,000 years, more than 85% of the species living in the ocean went extinct. And while that seems like a long time to us, that’s very quick in geologic time. The marine version of the end-Permian extinction took up 100,000 years out of the entire 3,800,000,000 years that life has existed—the equivalent to 14 minutes out of a whole year.
To learn what happened to life on land, Viglietti, Angielczyk, and their colleagues examined fossils from 588 four-legged fossil animals that lived in what’s now South Africa’s Karoo Basin at the time of the Permian mass extinction.
