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W. Andrew Barr

I am a paleoanthropologist interested in understanding the environmental context of early human evolution. Global climate change is often framed as a major driver of human adaptation and evolution. However, despite much theorizing, we have surprisingly limited evidence of the impact of global climate on evolutionary events such as the origin of Homo. I conduct fieldwork and apply quantitative analytical methods in the lab to help fill these knowledge gaps.

Currently, I am a Visiting Assistant Professor in the Center for the Advanced Study of Human Paleobiology and the Department of Anthropology at The George Washington University in Washington, D.C.

My research uses principles of functional morphology (Barr 2014, Barr and Scott, 2014, Scott and Barr, 2014) to characterize the habitat-specific adaptations of fossil mammals. I use these results to trace the prevalence of different habitats through time, as a proxy for the environmental conditions faced by hominins. My recent work in the Shungura Formation of Ethiopia (funded by Wenner-Gren) shows that the Omo River provided an effective buffer, protecting human ancestors from the effects of global climate trends (Barr, 2015). Furthermore, I investigate the role of climate using modeling approaches. Previous research has shown a spike in the rate of new species origination in Africa around 2.8 Ma, including the current first appearance of Homo. My recent simulation study (Barr, 2017) shows that this influx of new species is indistinguishable from background rate fluctuations. Thus, available evidence does not support a simple link between climate trends and the origin of Homo.

The context in which Homo arose remains murky due to limited fossil evidence from the latest Pliocene and earliest Pleistocene in eastern Africa. To increase our knowledge of this time period, I conduct fieldwork in Ethiopia with the Mille-Logya Research Project (MLP) in sediments of this age. Continued fieldwork and forthcoming descriptions of the MLP fauna and hominin fossils will provide new data from this poorly known time period in human evolution.