Chapter 22 Notes: Species and Speciation: Figure WN22.2 - “Descent with modification” leads to phenotypic clustering.

Figure WN22.2 - “Descent with modification” leads to phenotypic clustering.

Figure WN22.2. “Descent with modification” leads to phenotypic clustering. (A) Initially, a population of individuals is randomly spread across the space of possible phenotypes, represented here by a two-dimensional square. Over time, individuals reproduce and change phenotype by random mutation, and clusters of distinct phenotypes form (B,C). This clustering, produced by random diffusion of reproducing individuals, was pointed out by Felsenstein (1975) and is known as the “pain in the torus.” The phenomenon was rediscovered by Young et al. (2001). Both these papers assume movement through actual space, not phenotypic space, but the principle is the same. (Reprinted from Fig. 1 of Young et al. 2001. http://www.nature.com.)

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