DISSERTATION RESEARCH: Macroevolutionary Consequences of Abundance in Paleogene Bivalves

确定物种的生态特征对灭绝和起源速率的相对影响对于理解生物多样性的产生和维持至关重要。人们普遍认为影响进化速度的一个因素是物种内个体的丰富性。这项研究测试了丰度是否能准确地预测白垩纪末期(6500万-3000万年前)白垩纪末大灭绝后三个海洋双壳类超家族在恢复和多样化过程中的进化速度。由于丰度与其他被认为影响进化速度的生物特征相关，因此正在使用多变量统计方法来确定丰度对宏观进化模式的直接和间接贡献。这项研究的数据是通过在美国墨西哥湾沿岸平原的实地考察和利用现有的古生物收集来收集的。这项研究将首次测试多种生物特征对海洋生态系统演化速度随地质时间尺度的相对影响。这些结果将促进对进化动力学的理解，并将为预测物种对当前环境变化的敏感性提供信息。将为这项研究收集大量化石材料，并将通过古生物学数据库为未来的研究提供数据。研究成果和方法将通过在沿海、平原和芝加哥南部社区的推广计划向学生和公众传播。

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.