An Ecosystem approach to Hominin Environments in the East African plio-Pleistocene

Smithsonian Institution, Washington DC

Investigators

Abstract

The study of human adaptation and evolution is intimately tied to knowledge of the environments in which humans evolved. These environments have space-time dimensions that must be understood in order to answer key questions about how environmental change affected early human evolution. According to one hypothesis, global climatic change between 2 and 3 million years ago was responsible for a major evolutionary radiation of mammals in Africa that included our direct ancestors. It is likely that climate did affect human evolution in some way, but exactly how and when this happened remains controversial. Some researchers believe that empirical evidence has not yet demonstrated the role of climate change in African mammal evolution. Preservation biases in the fossil record, differing data-collection methods, and varying levels of chronological and spatial resolution across fossil localities in Africa must be carefully examined and controlled in order to rigorously test the climate change hypothesis. This project will test the linkage between the global climatic record and changes in mammal faunas from terrestrial ecosystems in Africa between 5 and 1 million years ago. The focus will be on the Turkana Basin of Kenya and Ethiopia and the Hadar-Dikika region of northern Ethiopia, two of the major sources of fossils of human ancestors (hominins) as well as a rich record of other mammals. The Turkana Basin Paleoecology Database will be assembled from existing separate datasets, museum collections, and new field initiatives that use standardized sampling of selected stratigraphic intervals. Comparisons with the Hadar-Dikika region will draw from the existing Hadar Faunal Database and new data collected in the field. The resulting information will demonstrate what environments were inhabited by early hominins in East Africa and how these environments changed through time, what mammal species early hominins were most closely associated with, and how global climate records correlate with terrestrial faunal and archeological change at different spatial and temporal scales. Information and interpretations derived from this research will be made available to the public via scientific journals, public science education media, and the internet.