Eastern African environmental variation and its role in the evolution and cultural change of Homo over the last 1 million years

R.L. Lupien, James M. Russell, A. Subramanian, R. Kinyanjui, E.J. Beverly, K.T. Uno, P. de Menocal, R. Dommain, Richard Potts

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Characterizing eastern African environmental variability on orbital timescales is crucial to evaluating the hominin evolutionary response to past climate changes. However, there is a dearth of high-resolution, well-dated records of ecosystem dynamics from eastern Africa that cover long time intervals. In the last 1 Myr, there were significant anatomical and cultural developments in Homo, including the origin of Homo sapiens. There were also major changes in global climatic boundary conditions that may have affected eastern African environments, yet potential linkages remain poorly understood. We developed carbon isotopic records from plant waxes (δ 13C wax) and bulk organic matter (δ 13C OM) from a well-dated sediment core spanning the last ∼1 Myr extracted from the Koora Basin, located south of the Olorgesailie Basin, in the southern Kenya rift. Our record characterizes the climatic and environmental context for evolutionary events and technological advances recorded in the adjacent Olorgesailie Basin, such as the transition from Acheulean to Middle Stone Age tools by 320 ka. A significant shift toward more C 4-dominated ecosystems and arid conditions occurred near the end of the mid-Pleistocene Transition, which indicates a link between equatorial eastern African and high-latitude northern hemisphere climate. Environmental variability increases throughout the mid- to late-Pleistocene, superimposed by precession-paced packets of variability modulated by eccentricity. An interval of particularly high-amplitude climate and environmental variability occurred from ∼275 ka to ∼180 ka, synchronous with evidence for the first H. sapiens fossils in eastern Africa. These results support the ‘variability selection hypothesis’ that increased environmental variability selected for adaptable traits, behaviors, and technology in our hominin ancestors.

Original languageEnglish (US)
Article number103028
Number of pages14
JournalJournal of Human Evolution
Volume157
DOIs
StatePublished - Aug 2021

Bibliographical note

Funding Information:
We wish to thank Laura Messier for laboratory assistance and the members of the Olorgesailie Drilling Project and the Hominin Sites and Paleolakes Drilling Project for insightful discussions. We would also like to thank the editors and reviewers Sarah Feakins, Robert Patalano, and an anonymous reviewer for their thorough and constructive feedback toward improving the article. We acknowledge the National Museums of Kenya, the Oldonyo Nyokie Group Ranch, and the Olorgesailie field team led by J.M. Nume and J.N. Mativo. Research and drilling permits were provided by the Kenyan National Council for Science and Technology, the Kenya Ministry of Petroleum and Mining, and the National Environmental Management Authority of Kenya and facilitated by the cooperative agreement between the National Museums of Kenya and Smithsonian Institution. We thank DOSECC Exploration Services for drilling supervision, Drilling and Prospecting International for drilling services, and the LacCore and CSDCO (University of Minnesota) for initial core processing and sampling. This work was supported by the Peter Buck Fund for Human Origins Research to the Smithsonian ; the William H. Donner Foundation to R.P.; the Ruth and Vernon Taylor Foundation to R.P.; and the National Science Foundation (grant number EAR 1826938 ) to J.M.R.

Funding Information:
We wish to thank Laura Messier for laboratory assistance and the members of the Olorgesailie Drilling Project and the Hominin Sites and Paleolakes Drilling Project for insightful discussions. We would also like to thank the editors and reviewers Sarah Feakins, Robert Patalano, and an anonymous reviewer for their thorough and constructive feedback toward improving the article. We acknowledge the National Museums of Kenya, the Oldonyo Nyokie Group Ranch, and the Olorgesailie field team led by J.M. Nume and J.N. Mativo. Research and drilling permits were provided by the Kenyan National Council for Science and Technology, the Kenya Ministry of Petroleum and Mining, and the National Environmental Management Authority of Kenya and facilitated by the cooperative agreement between the National Museums of Kenya and Smithsonian Institution. We thank DOSECC Exploration Services for drilling supervision, Drilling and Prospecting International for drilling services, and the LacCore and CSDCO (University of Minnesota) for initial core processing and sampling. This work was supported by the Peter Buck Fund for Human Origins Research to the Smithsonian; the William H. Donner Foundation to R.P.; the Ruth and Vernon Taylor Foundation to R.P.; and the National Science Foundation (grant number EAR 1826938) to J.M.R.

Publisher Copyright:
© 2021 Elsevier Ltd

Keywords

  • Biomarkers
  • Carbon isotopes
  • East Africa
  • Human evolution
  • Organic geochemistry
  • Paleoclimate

Continental Scientific Drilling Facility tags

  • ODP

PubMed: MeSH publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Journal Article

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