Brief Communication Intermittence for Humans Living 45,000 Years Ago: From Eurasia to the Americas

Abstract

From northeastern Eurasia to the Americas, a three-stage spread of modern humans is considered through large-scale intermittence (exploitation/ relocation). Conceptually, this work supports intermittence as a real strategy for colonization of new habitats. For the fi rst stage, northeastern Eurasia travel, we adapt our model to archaeological dates determining the diffusion coeffi cient (exploitation phase) as D = 299.44 km/yr and the velocity parameter (relocation phase) as vo = 4.8944 km/yr. The relative phase weight (≈0.46) between both kinds of motions is consistent with a moderate biological population rate (r ≈ 0.0046/yr). The second stage is related to population fragmentation. The last stage, reaching Alaska, corresponds essentially to relocation (vo ≈ 0.75 km/yr). In a general framework, scientists suggest that the fi rst Americans were Asian hunters following prey eastward across Beringia, today the submerged land between Asia and Alaska. Starting from Asia, particularly Siberia around 45,000 BP, the expansion of modern humans to the Americas has been the subject of extensive debates, including genetic aspects (Reich et al. 2012). In fact, a three-stage modern human expansion process into the Americas (Alaska) has been conjectured (Kitchen et al. 2008). That scheme integrates interdisciplinary studies, including mathematical analyses, among others. Particularly, the Fisher-Kolmogorov reaction-diffusion equation (Murray 2002; Benguria and Depassier 2005) was used to support the three-stage expansion from northeastern Eurasia to the Americas (Hamilton and Buchanan 2010). The respective wave-front solution represents a continuous advance without considering niche exploitation and relocation as two independent phases. [For reviews and criticisms of reaction diffusion equations applied to archaeological problems, see Steele (2009). For applications to language competition, population growth, and dispersal, see Kandler (2009). Other applications of wave-front spreads,