Doctoral Dissertation Improvement-Paleoecology of the Upper Laetolil Beds, Laetoli, Tanzania: Its Implications for Hominid Evolution

New York University, New York NY

Investigators

Abstract

The analysis of the structure of past ecosystems, or paleoecology, is regarded as an essential component of contemporary studies of human evolution. Through detailed investigations of the association between ecology and evolutionary transformation it is possible to generate hypotheses about the factors that ultimately contributed to major events in the evolutionary history of hominids (humans and their close extinct relatives), including speciation, adaptive shifts, and extinctions. Previously, interpretations of the paleoecology at the important fossil hominid site of Laetoli in Tanzania (dating to 3.5-3.8 million year ago) have suggested that it is either an arid to semi-arid grassland with patches of bush and woodland or a more heavily wooded habitat. The objective of this project is to resolve this contentious issue by more thoroughly documenting the paleoecological setting at Laetoli. This study will utilize a range of data from the fossil faunas from Laetoli, and will apply a variety of methods and techniques to these data, such as indicator species, ecomorphology, ecological structure and community composition analyses. The project will also investigate, for the first time, fine-grained ecological distinctions between individual stratigraphic horizons and different sub-localities. The overall goal will be to present a more detailed, more comprehensive, and more informed assessment of the paleoecology at Laetoli. This will take into account the broad spectrum of faunal evidence available, the geographical and temporal complexity represented at the site, and the limitations imposed by taphonomic factors. The results of this project will provide a better understanding of the types of habitats exploited by early hominids, and lead to a more critical appreciation of their habitat preferences. The project will ultimately provide an important building block in developing broader scale macroevolutionary models that are essential for understanding and interpreting the contexts that shaped human evolution.