Study examines human cultural adaptation and effects of ancient climate change

July 8, 2021

Arizona State University researchers will help lead a $1.2 million, multi-agency project that will use a new theoretical framework and cutting-edge technology to address a long-standing question: How ecological factors there are millions of years affect the evolution of our ancestors?

The possible answers intrigued the WM Keck Foundation so much that it awarded the international team one of its largest grants to explore this question.

Map of the two research sites in Ethiopia – Hadar and Woranso-Mille – research sites where important ancient hominin fossils were discovered and are now being compared to explain why different species cohabited, but did not overlap in space. Google Earth image.
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The funds will support a systematic and integrated investigation into why two world-renowned adjacent fossil study areas in the Afar region of Ethiopia – Hadar and Woranso-Mille – have revealed strikingly different records from the earliest predecessors of our genus human.

ASU’s Institute of Human Origins has over 40 years of history of exploration and discovery at Hadar, beginning with the 1974 discovery of “Lucy”, the 3.2-year-old Australopithecus afarensis fossil. million years ago, by the institute’s founding director, Donald Johanson. Since then, scientists have found hundreds more fossils of Lucy’s species in Hadar, but no other hominid species that may have lived at the same time.

Just 30 miles north of Hadar, a research project at Woranso-Mille that began in 2005, led by the institute’s new director, Yohannes Haile-Selassie, has yielded many fossils not only of the species of Lucy, but at least two others – including one whose foot seems to be suited for tree climbing. Some of these different species existed at the same time.

Haile-Selassie and Kaye Reed, research associate at the Institute of Human Origins and President’s Professor in the School of Human Evolution and Social Change; Beverly Saylor of Case Western Reserve University; and Naomi Levin of the University of Michigan are co-principal investigators on the WM Keck Foundation-awarded project. Case Western Reserve University is the institution responsible for the award.

Other participating institutions include Addis Ababa University, University of Aix Marseille, University of Barcelona, ​​Berkeley Center for Geochronology, Ohio University and University of Southern California .

Haile-Selassie and Reed will lead efforts to compare and analyze the Hadar and Woranso-Mille fossil record to assess links between rift establishment, landscape-scale heterogeneity, and mammalian diversity, including included among the hominins.

“This multidisciplinary integration of physical, chemical and biological evidence will allow us to assess differences in the ecology of closely related early human ancestors and provide insight into the origins of our own genus,” said Haile-Selassie, who is a professor at ASU. School of human evolution and social change.

The transformative aspect of this project is that it attempts, for the first time, to directly compare Hadar and Woranso-Mille to examine the selective environmental pressures that might have driven human evolution.

Seizing this opportunity involves hiring about thirty scientists whose expertise ranges from geology and paleoanthropology to geochronology and paleoclimate, including Christopher Campisano, associate researcher at the Institute of Human Origins and associate professor at the École human evolution and social change; David Feary, research professor at the School of Earth and Space Exploration; and Denise Su, who will join the Institute of Human Origins and the School of Human Evolution and Social Change as a research associate and associate professor in August.

Over the next three years, the team will gather samples and data from both areas to gain a more detailed understanding of the two sites as they existed over 3 million years ago.

Reed will refine habitat reconstructions using faunal, isotope and depositional data for specific areas of Hadar stratigraphy and work with Su to compare differences in mammals and habitats between the two sites.

“This is the first time we have had the opportunity to compare the paleoecology of single fauna and hominids from adjacent areas during the same time period,” Reed said. “It will give us a level of detail that we didn’t have and allow us to explore why different species lived in close proximity to each other but did not overlap in space. It’s very exciting.”

Campisano will lead the geological efforts at Hadar, guiding and working with a team of geoscientists new to Hadar to collect high-resolution samples and data at particular time intervals to compare to Woranso-Mille.

“Better integrating the geology and paleoenvironments of Hadar with adjacent project sites has been my goal for over a decade,” said Campisano. “The chance to do so, and with a suite of analytical techniques new to Hadar, is an intriguing opportunity.”

Su will be primarily responsible for reconstructing the paleoenvironment at Woranso-Mille using faunal evidence and integrating geological, isotopic and paleobotanical data.

“Woranso-Mille is the only Pliocene site that documents at least two species of contemporary hominids. Reconstructing its paleoenvironment will be crucial to understanding how hominids shared the landscape,” Su said.

The ASU team is complemented by Feary, who will develop a high-resolution 3D model of the Hadar concentration area using recently developed aerial photogrammetric techniques as the basis for geological and habitat reconstructions.

“The WM Keck Foundation Prize provides an incredible opportunity to use new research tools to address fundamental questions of paleoenvironmental and human evolution,” Feary said.

If successful, this project will reveal the spatial context of hominin diversity records – one of the great challenges to understanding human evolution and a fundamental question of biodiversity.

“This project builds on decades of field studies, laboratory analyzes and museum work, which, combined with the differences in hominin species in neighboring but distinct geological landscapes, provide an unparalleled opportunity precedent to understanding the ecological features that influence human diversity and evolution,” said Saylor, who is the project’s principal investigator.

Haile-Selassie added, “This project takes human origins research to another level. Understand how tectonics and rifting may have played a role in the diversity or lack of diversity of early human ancestors, and how these forces may have shaped the landscapes and associated climates in which our early ancestors diversified or became extinct would be a major breakthrough in paleoanthropology. .”

The Ethiopian Authority for Research and Conservation of Cultural Heritage and the Afar Regional Government will facilitate local permits for this research.

The W. M. Keck Foundation was established in 1954 in Los Angeles by William Myron Keck, founder of The Superior Oil Company. One of the nation’s largest philanthropic organizations, the W. M. Keck Foundation supports outstanding research in science, engineering, and medicine. The foundation also supports undergraduate education and maintains a program in Southern California to support arts and culture, education, health, and community service projects.

ASU has received a number of Keck Foundation awards; the most recent was a science and engineering grant in 2018 related to materials science.

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