Determining the relative influences of species' ecological characteristics on extinction and origination rates is critical in understanding the generation and maintenance of biodiversity. One factor widely believed to influence evolutionary rates is the abundance of individuals within species. This study tests whether abundance accurately predicts evolutionary rates in three superfamilies of marine bivalves during their recovery and diversification following the end-Cretaceous mass extinction (65-30 million years ago). Because abundance covaries with other biological characteristics believed to influence evolutionary rates, a multivariate statistical approach is being used to determine the direct and indirect contributions of abundance to macroevolutionary patterns. Data for this study are being gathered through fieldwork in the U.S. Gulf Coastal Plain and the use of existing paleontological collections.
This study will provide the first test of the relative influences of multiple biological characteristics on evolutionary rates in marine ecosystems over geologic time scales. The results will advance understanding of evolutionary dynamics and will inform predictions of the sensitivities of species to current environmental change. An extensive collection of fossil material will be gathered for this study and resulting data will be available for future research via the Paleobiology Database. Research results and approaches will be disseminated to students and the general public through outreach programs in coastal plain and south side Chicago communities.
