Climatic variability and hominin dispersal: the accumulated plasticity hypothesis

Summary

It has long been known that temporally unstable environments are likely to promote the evolution of plastic adaptations, whilst it is equally clear that such adaptations are characteristic of successful colonizers. These two established findings, however, are rarely related. This contribution bridges this gap using a very simple evolutionary algorithm that tracks the evolution of plasticity under various climatic regimes, allowing for the construction of an index of climate-mediated dispersal potential.

Model results suggest populations accumulate high levels of plasticity during highly variable climatic phases and express such heightened plasticity via dispersal in subsequent low-variability phases. This putative scenario is referred to as the Accumulated Plasticity Hypothesis, and is tested using a high-resolution precipitation record from Lake Tana, Ethiopia, together with the dates of the first Homo sapiens dispersal out of East Africa. The primary dispersal phase identified in the Lake Tana record between 112ka and 97ka accords remarkably well with the timing of Homo sapiens arrival at the Israeli sites of Qafzeh and Skhul, and with dated ‘Southern Route’ sites in Yemen and Oman. This dispersal chronology is discussed in relation to recent revisions of genetic dates for the origin of non-African modern humans.

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This Resource is Part of the Following Collections

• Simulating Social Complexity to Understand the Archaeological Past   •
• Society for American Archaeology 80th Annual Meeting, San Francisco, CA (2015)

Keywords

Spatial Coverage