Natural selection. III. Selection versus transmission and the levels of selection

TL;DR

This paper extends Williams' concept of evolutionary units by using the ratio of selection bias to transmission bias as a unifying framework for various biological phenomena and evolutionary theories.

Contribution

It introduces a general framework based on the ratio of selection to transmission bias, unifying diverse biological problems and evolutionary concepts.

Findings

Provides a unified view of mutation-selection balance and error thresholds.

Clarifies the role of multilevel selection and evolutionary units.

Deepens understanding of kin and group selection mechanisms.

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, Szathmary 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 Szathmary'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.