Drift and the causes of evolution

Sahotra Sarkar

in Causality in the Sciences

Published in print March 2011 | ISBN: 9780199574131
Published online September 2011 | e-ISBN: 9780191728921 | DOI:
Drift and the causes of evolution

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This chapter defends a stochastic dynamical interpretation of evolution under which drift does not emerge as an evolutionary cause, unlike mutation and selection. Rather, whether drift occurs in a population model depends on its constitutive assumptions, namely, whether the population size is finite. The same amount of selection makes quantitatively and qualitatively different predictions in finite and infinite population models: this is all that there is to drift. This argument is illustrated through the explicit solution of a haploid model in which differences in vital parameters lead to drift in the presence of selection. In the absence of these differences, the model reduces to a neutral model. In the infinite population limit, the standard results without drift also obtain. The stochastic dynamical interpretation is contrasted with the views that evolution is a theory of forces and the statistical interpretation of evolution.

Keywords: causality; drift; dynamical interpretation of evolution; evolution; selection; stochasticity

Chapter.  11406 words. 

Subjects: Logic

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