Ancient Mammal Relatives Cast Light On Recovery After Mass Extinction
Much work so far suggests that the survivors of mass extinctions often are presented with new ecological opportunities because the loss of many species in their communities allows them to evolve new lifestyles and new anatomical features as they fill the roles vacated by the victims.
However, it turns out that not all survivors respond in the same way, and some may not be able to exploit fully the new opportunities arising after a mass extinction. A team of researchers from the University of Lincoln, the Field Museum of Natural History in Chicago, the Museum für Naturkunde in Berlin, and the University of Bristol examined how a group of ancient relatives of mammals called anomodonts responded in the aftermath of the largest mass extinction in Earth history. Their work, published this week in Proceedings of the Royal Society B and titled “Decoupling of morphological disparity and taxic diversity during the adaptive radiation of anomodont therapsids,” shows that anomodonts remained anatomically conservative even as the number of species rebounded during the recovery.
The mass extinction at the end of the Permian Period, about 252 million years ago, had profound effects on organisms on land and in the sea, with as many as 90% of marine organisms and 70% of terrestrial species becoming extinct. “Groups of organisms that survive such a mass extinction are said to have passed through an evolutionary bottleneck analogous to the genetic bottleneck that may occur in a population if many of its members die off,” said Dr. Marcello Ruta of the University of Lincoln, the lead author of the study. “At the population level, a genetic bottleneck sometimes allows the population to move to a new evolutionary trajectory, but other times it constrains the future evolution of the population.”
Read the full story here.