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12.3: The Big Picture - The Assimilation Hypothesis

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    How do researchers make sense of all of these modern Homo sapiens discoveries that cover over 300,000 years of time and stretch across every continent except Antarctica? How was modern Homo sapiens related to archaic Homo sapiens?

    The Assimilation hypothesis proposes that modern Homo sapiens evolved in Africa first and expanded out but also interbred with the archaic Homo sapiens they encountered outside Africa (Figure 12.20). This hypothesis is powerful since it explains why Africa has the oldest modern human fossils, why early modern humans found in Europe and Asia bear a resemblance to the regional archaics, and why traces of archaic DNA can be found in our genomes today (Dannemann and Racimo 2018; Reich et al. 2010; Reich et al. 2011; Slatkin and Racimo 2016; Smith et al. 2017; Wall and Yoshihara Caldeira Brandt 2016).

    African Homo erectus expands and gives rise to archaics and modern Homo sapiens groups.
    Figure 12.20: This diagram shows archaic humans, having evolved from Homo erectus, expanded from Africa and established the Neanderthal and Denisovan groups. In Africa, archaic humans evolved modern traits and expanded from the continent as well, interbreeding with two archaic groups across Europe and Asia. Credit: Assimilation Model (Figure 12.23)l original to Explorations: An Open Invitation to Biological Anthropology by Keith Chan and Katie Nelson is under a CC BY-NC 4.0 License.

    While researchers have produced a model that satisfies the data, there are still a lot of questions for paleoanthropologists to answer regarding our origins. What were the patterns of migration in each part of the world? Why did the archaic humans go extinct? In what ways did archaic and modern humans interact? The definitive explanation of how our species started and what our ancestors did is still out there to be found. You are now in a great place to welcome the next discovery about our distant past—maybe you’ll even contribute to our understanding as well.

    This page titled 12.3: The Big Picture - The Assimilation Hypothesis is shared under a CC BY-NC 4.0 license and was authored, remixed, and/or curated by Keith Chan (Society for Anthropology in Community Colleges) via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.