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Influence of Plio‐Pleistocene aridification on human evolution: Evidence from paleosols of the Turkana Basin, Kenya
Author(s) -
Wynn Jonathan Guy
Publication year - 2004
Publication title -
american journal of physical anthropology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.146
H-Index - 119
eISSN - 1096-8644
pISSN - 0002-9483
DOI - 10.1002/ajpa.10317
Subject(s) - aridification , plio pleistocene , paleosol , structural basin , ecology , pleistocene , habitat , biology , arid , geography , paleontology , loess
New stable carbon isotope measurements, coupled with paleoprecipitation estimates, both from Plio‐Pleistocene paleosols of the Turkana Basin, Kenya, provide a high‐resolution record of aridification and increasing C 4 biomass during the past 4.3 Ma. This aridification trend is marked by several punctuations at 3.58–3.35, 2.52–2, and 1.81–1.58 Ma, during which the running mean and variance of δ 13 C and paleoaridity estimates increase, suggesting that the proportion of C 4 biomass increases in savanna mosaics during periods of heightened aridity. Increase in C 4 biomass during these aridification events not only increases the proportion of open habitats, but increases the spatial neg‐entropy, or heterogeneity of the ecosystem. The aridification events identified correspond to intervals of increased turnover, but more importantly, increased diversity of bovids. Although the record of hominins from the Turkana Basin lacks the temporal resolution and diversity of the bovid record, the aridification intervals identified are marked by similar increases in the diversity and turnover of hominins. These results support the hypothesis that hominins evolved in savanna mosaics that changed through time, and suggest that the evolution of bovids and hominins was driven by shifts in climatic instability and habitat variability, both diachronic and synchronic. Am J Phys Anthropol, 2003. © 2003 Wiley‐Liss, Inc.