title: Stochasticity in evolution.
abstract: The debate over the role of stochasticity is central in evolutionary biology, often summarised by whether or not evolution is predictable or repeatable. Here we distinguish three types of stochasticity: stochasticity of mutation and variation, of individual life histories and of environmental change. We then explain when stochasticity matters in evolution, distinguishing four broad situations: stochasticity contributes to maladaptation or limits adaptation; it drives evolution on flat fitness landscapes (evolutionary freedom); it might promote jumps from one fitness peak to another (evolutionary revolutions); and it might shape the selection pressures themselves. We show that stochasticity, by directly steering evolution, has become an essential ingredient of evolutionary theory beyond the classical Wright-Fisher or neutralist-selectionist debates.
authors.affiliation: Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175, 1919 Route de Mende, Montpellier cedex 5, France. thomas.lenormand@cefe.cnrs.fr
authors.forename: Thomas
authors.initials: T
authors.lastname: Lenormand
authors.forename: Denis
authors.initials: D
authors.lastname: Roze
authors.forename: François
authors.initials: F
authors.lastname: Rousset
mesh_terms: D000220:Adaptation, Biological; D005075:Biological Evolution; D004777:Environment; D040961:Genetic Drift; D014644:Genetic Variation; D009154:Mutation; D011157:Population Dynamics; D012641:Selection, Genetic; D013269:Stochastic Processes; D013816:Thermodynamics