Doctoral Dissertation Improvement: Investigating the Obstetrical Dilemma: Patterns of Morphological Integration in the Primate Pelvis

点击翻译按钮获取中文摘要

Modern human birth is the most difficult of any living great ape, and is believed to be the result of a compromise between two competing selective forces in later hominins: one to allow for efficient obligate bipedal locomotion, and one to permit parturition of a large-brained and large-bodied offspring - the "obstetrical dilemma." Past studies have supported this hypothesis through analyses which compare means and proportions of pelvic traits between hominins and other apes, differences that are believed to be the result of past selection pressures for divergent functional requirements. In addition, correlations between traits (i.e. patterns of integration) may also respond to selection, and thus analyzing interspecific differences in pelvic patterns of integration provides a new route to addressing this evolutionary problem. This project uses evolutionary quantitative methods to test hypotheses about the roles that selection pressures for bipedalism and obstetrics have played in the evolution of hominin pelvic morphology. It will reconstruct past selection pressures in the pelves of hominins and quantitatively determine the roles that pressures for bipedalism and obstetrics played in causing the morphological changes seen across species of hominins. The research reveals if traits thought to be adaptations for bipedalism or parturition are actually correlated responses to selection on other traits rather than having been direct products of selection. Finally, the research tests if patterns of integration in the pelves of humans have evolved in response to conflicting selection pressures relating to the obstetrical dilemma and what role these patterns have played in the evolution of hominin pelvic morphology. In addition to furthering understanding of the evolutionary dilemma of the trade-offs between walking upright bipedally and giving birth to large-brained infants, this project will further the co-PI's training in an interdisciplinary approach based in evolutionary genetics, biology, statistics, and biological anthropology, which may provide data on broader questions in evolutionary biology relating to the role of patterns of integration in large-scale adaptations, as well as their ability to facilitate evolutionary change. There are also many avenues for the mentoring of undergraduates, allowing them to participate in different levels of analyses and providing hands-on experience in conducting science.