Todd, P.M., and Miller, G.F. (1991). On the sympatric origin of species: Mercurial mating in the quicksilver model. In R.K. Belew and L.B. Booker (Eds.), Proceedings of the Fourth International Conference on Genetic Algorithms (pp. 547-554). San Mateo, CA: Morgan Kaufmann.

Abstract

Traditional models of how interbreeding populations split apart into reproductively isolated populations (species) require the intervention of geographic barriers to mating or disruptive selection. We develop an alternate Quicksilver Model of speciation, and show through simulation that sympatric (barrier-less) speciation can occur spontaneously, frequently, and robustly even in the absence of external divisive forces given certain broad conditions: (1) individuals have evolvable mate preferences based on degree of similarity to oneself along certain phenotypic dimensions, and (2) individuals compete to match the mate preferences of other individuals, and to have appropriate mate preferences themselves (i.e. sexual selection exists). Our model's success defends the notion of sympatric speciation against charges that it is impossible, implausible, or unlikely. It also offers an new vision of macroevolution based on appreciating the way modest psychological mechanisms of mate choice can have strong emergent effects on macroevolutionary dynamics.



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