title: Natural selection. III. Selection versus transmission and the levels of selection.
abstract: George Williams defined an evolutionary unit as hereditary information for which the selection bias between competing units dominates the informational decay caused by imperfect transmission. In this article, I extend Williams' approach to show that the ratio of selection bias to transmission bias provides a unifying framework for diverse biological problems. Specific examples include Haldane and Lande's mutation-selection balance, Eigen's error threshold and quasispecies, Van Valen's clade selection, Price's multilevel formulation of group selection, Szathmáry and Demeter's evolutionary origin of primitive cells, Levin and Bull's short-sighted evolution of HIV virulence, Frank's timescale analysis of microbial metabolism and Maynard Smith and Szathmáry's major transitions in evolution. The insights from these diverse applications lead to a deeper understanding of kin selection, group selection, multilevel evolutionary analysis and the philosophical problems of evolutionary units and individuality.
authors.affiliation: Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA. safrank@uci.edu
authors.forename: S A
authors.initials: SA
authors.lastname: Frank
mesh_terms: D005075:Biological Evolution; D014644:Genetic Variation; D008954:Models, Biological; D011157:Population Dynamics; D012641:Selection, Genetic; D013269:Stochastic Processes; D013997:Time Factors