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Powell Russell | Fellow Visitor
2012-05-30 - 2012-06-21 | Research area: EvoDevo
Human Evolution: Past, Present, and Future
This project explores conceptual and methodological problems in the study of human evolution. There is a tendency in both scientific and humanistic disciplines to think of biological evolution in humans as significantly impeded if not completely overwhelmed by the robust cultural and technological capabilities of the species. The central aim of this research is to make sense of and evaluate this claim. Doing so will require fleshing out the argument that humans are ‘insulated’ from ordinary evolutionary mechanisms in terms of our contemporary biological understandings of phenotypic plasticity, niche construction, and cultural transmission. In addition, I will consider some obvious objections to the above argument based on the growing literatures related to gene-culture coevolution and recent positive selection on the human genome, in addition to some less common objections relating to the connection between plasticity, population size and evolvability. I contend, however, that the case for continued biological evolution in humans is significantly more persuasive than it is usually taken to be. This is because both the ‘human evolutionary stasis argument’ (as I call it) and its various detractor theories are premised on a fundamental conceptual flaw: they take evolutionary stasis for granted, since they fail to conceive of stabilizing selection as a type of evolution and drift as a universal tendency that dominates in the absence of selection (or other evolutionary forces). Without the continued operation of natural selection, the very properties that are purported to reduce the evolutionary response to selection in humans would themselves drift into non-functionality. My conclusion will be that properly conceived, biological evolution is a permanent and ineradicable fixture of any species, including Homo sapiens. I will then apply this conclusion and the various lines of reasoning on which it is predicated to contemporary problems in biomedical science. In particular, I will consider the implications of human evolutionary history for medicine, and medicine for the future of human evolution. Evolutionary perspectives have rarely been integrated in medical practice and education, in part due to the strong connection between proximate causation and clinical outcomes, and in part due to the sordid history of Darwinian perspectives in bioethics and social policy. I will develop and defend the counterintuitive claim that the greater the effectiveness of classical medicine, the greater the need for human genetic modification, given the former’s predictable population-genetic effects. This conclusion will follow on the heels of the above conceptual and empirical analysis of the relation between selection, drift, and evolutionary buffering mechanisms.