2011-05-05
SES Professor William Ausich Featured In Proceedings of the National Academy of Sciences
Posted by: Michael Seufer
William I. Ausich and colleagues published a studying documenting the role of predators in the geological history of crinoids. This paper appeared in recent issue of the Proceedings of the National Academy of Sciences.
"The Signature of Vertebrate Predation in Carboniferous Crinoid Diversity" by Lauren Cole Sallana, Thomas W. Kammerb, William I. Ausichc, Lewis A. Cookb [ aDepartment of Organismal Biology and Anatomy, University of Chicago, bDepartment of Geology and Geography, West Virginia University, and cSchool of Earth Sciences, The Ohio State University] was published on line May 2 in the Proceedings of the National Academy of Sciences.
Data presented here demonstrates the interplay between the evolutionary success of different kinds of Devonian and Mississippian predators and prey. The evolutionary radiation of Mississippian crinoids occurred after the end-Devonian (Hangenburg) extinction event. However, new more efficient predators evolved during the ensuing 20 million years eventually overwhelming the defenses of many prey species.
Beyond a more clear understanding of the evolutionary history of Late Devonian and Mississippian fishes and crinoids, the significance of this study is twofold. First, the evolutionary history of Devonian and Mississippian predator extinction and prey radiation demonstrates that processes operating in ecological time (predator-prey dynamics) can be scaled up to processes operating in evolutionary time (tens of millions of years). Second, phenomenon, "legacy adaptations," is defined, which is the maintenance of an adaptation(s) that continued through evolutionary history, even though the initial reason for that adaptation was no longer a factor. For example, Early Mississippian camerate crinoid adaptations were best suited to defensive strategies for the extinct nipping Devonian predaceous fish. However, the newly evolved Mississippian predators exhibited novel shell-crushing dentitions, which were more than a match for the legacy adaptations, which largely failed. These results demonstrate that extinction and introduction of predators can have devastating and unexpected effects over long time spans.
See the following story and Google "winners of mass extinction": http://www.sciencedaily.com/releases/2011/05/110502151347.htm
