A comprehensive understanding of a species' evolutionary history includes determining the ecological factors that drove its adaptations. All species occupy a particular ecological niche whose breadth is determined by the interplay of abiotic (e.g., climate and dispersal barriers) and biotic (e.g., competition) influences. The niche of a species is rarely static through time and the inevitable changes can result in a variety of outcomes, including further adaptation, speciation and extinction. Although it has historically been difficult to reconstruct the ecological niches of fossil taxa, recently developed paleoecological techniques, mean that it is now possible to test hypotheses about the role of ecology might have played in the separate evolutionary histories of two important early hominin lineages.
Determining how our early human ancestors interacted with their environments is fundamental for understanding human evolutionary history. The fossil record suggests that our genus, Homo, originated in eastern Africa around 2.4 million years ago (Ma), and shared the environment with a closely related species called Paranthropus boisei. However, the record also suggests that by approximately 1.3 Ma, the Paranthropus lineage went extinct and Homo had expanded its geographical range outside of Africa. Although these lineages coexisted in time, we lack a logical framework for testing hypotheses related to their ecology during this period. This dissertation project by doctoral student David Patterson (under the supervision of Dr. René Bobe, The George Washington University) will contribute to addressing these gaps in our knowledge by using novel methods to generate the first high-resolution reconstruction of the ecological niches of these two lineages.
This project combines quantitative methods from mammalian community ecology with stable isotope geochemistry to investigate the ecological niches of Homo and Paranthropus within a spatially constrained ancient ecosystem. The proposed study will use paleoecological data collected directly from localities where these hominin fossils occur, and from archaeological sites dated to between approximately 2.0 and 1.4 Ma in the Koobi Fora Formation of northern Kenya. By concentrating on specific fossil assemblages within the same region, this study will provide new insights into the ecological niches of these two lineages.
The impact of this research will be amplified via the Co-PI's involvement with the Evolution of Terrestrial Ecosystems (ETE) program at the National Museum of Natural History (NMNH) and with the Koobi Fora Field School (KFFS). As part of ETE, the Co-PI will disseminate project results to educators through lectures at sponsored workshops and via the NMNH Q?rius Science Center. Additionally, the Co-PI will create a series of field- and laboratory-based entries for the Paleobiology Department's blogspace. The Co-PI will also participate in "The Scientist is in" program, which will give the public the opportunity to ask researchers about their research, as well as about other topics associated with human origins. Lastly, the Co-PI's fieldwork will be completed in conjunction with the KFFS. This collaborative effort between the National Museums of Kenya and GWU provides students from several countries, including Kenya, Ethiopia, South Africa, and the United States with hands-on field experience in paleoanthropology.
