NSF Postdoctoral Fellowship in Biology FY 2018

Grossnickle David M, Chicago IL

Investigators

Abstract

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2018, Research Using Biological Collections. The fellowship supports research and training of the fellow that will utilize biological collections in innovative ways. The fellow is studying evolutionary patterns in early mammals by examining fossil jaws. Since the Mesozoic Era, or the Age of Dinosaurs, mammals have been able to expand into many different geographical locations. However, how mammals were able to do this, and when they began their expansion are still heavily debated. The fellow will investigate this topic by collecting shape data on a large sample of fossil jaws from several natural history museums. Mammal jaws are especially informative because their shape is correlated with diet, thus providing clues about the mammals' ecologies. This research will contribute to our understanding of the origins of modern mammalian diversity. Further, the study focuses on evolutionary patterns before and after the Cretaceous-Paleogene (K-Pg) mass extinction event, thus offering information on how mammals are affected by mass extinction events. The fellow will expand the impact of this project by participating in numerous teaching, mentoring, and outreach opportunities, including the Discoveries in Geosciences Field School for K-12 teachers. It is often hypothesized that early mammals experienced an adaptive radiation following one of three globally transformative events: (1) the rise of flowering plants ~80 million years ago (Ma), (2) the K-Pg mass extinction 66 Ma, and (3) the Paleocene-Eocene Thermal Maximum 56 Ma. However, previous research on these hypotheses often lack ecological data or phylogenetic considerations, prohibiting proper testing of adaptive radiations. Thus, the primary aim of this project is to use ecomorphological and biomechanical data from jaw morphologies to examine macroevolutionary patterns, allowing robust tests of evolutionary hypotheses and providing novel insight into the origins of modern mammalian diversity. The fellow will collect measurements and shape data on hundreds of fossil jaws from the Cretaceous through Eocene (145-34 Ma), utilizing paleontological collections from several natural history museums. Hypotheses on the timing of the early mammal radiation will be tested by calculating morphological disparity patterns through time and using phylogenetic modeling methods to assess potential changes in the mode of evolution at different points in time. The fellow will be trained in advanced phylogenetic comparative methods and quantitative paleontological techniques, and results from this project will be presented at scientific conferences and published in peer-reviewed journals. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.