Bipedality and hair loss in human evolution revisited: The impact of altitude and activity scheduling

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Date
2016-05
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Mcode
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Language
en
Pages
11
72-82
Series
JOURNAL OF HUMAN EVOLUTION, Volume 94
Abstract
Bipedality evolved early in hominin evolution, and at some point was associated with hair loss over most of the body. One classic explanation (Wheeler 1984: J. Hum. Evol. 13, 91-98) was that these traits evolved to reduce heat overload when australopiths were foraging in more open tropical habitats where they were exposed to the direct effects of sunlight at midday. A recent critique of this model (Ruxton & Wilkinson 2011a: Proc. Natl. Acad. Sci. USA 108, 20965-20969) argued that it ignored the endogenous costs of heat generated by locomotion, and concluded that only hair loss provided a significant reduction in heat load. We add two crucial corrections to this model (the altitude. at which australopiths actually lived and activity scheduling) and show that when these are included there are substantial reductions in heat load for bipedal locomotion even for furred animals. In addition, we add one further consideration to the model: we extend the analysis across the full 24 h day, and show that fur loss could not have evolved until much later because of the thermoregulatory costs this would have incurred at the altitudes where australopiths actually lived. Fur loss is most likely associated with the exploitation of open habitats at much lower altitudes at a much later date by the genus Homo. (C) 2016 The Authors. Published by Elsevier Ltd.
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Australopiths, Thermoregulation, Incident radiation, Ambient temperature, Activity patterns, EARLY HOMININS, HOMO-ERECTUS, THERMOREGULATORY ADVANTAGES, ARDIPITHECUS-RAMIDUS, BEHAVIORAL ECOLOGY, MODELING APPROACH, ENERGETICS, PLIOCENE, ORIGIN, FIRE
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Citation
David-Barrett, T & Dunbar, R I M 2016, ' Bipedality and hair loss in human evolution revisited : The impact of altitude and activity scheduling ', JOURNAL OF HUMAN EVOLUTION, vol. 94, pp. 72-82 . https://doi.org/10.1016/j.jhevol.2016.02.006