title: The concept of fitness in fluctuating environments.
abstract: Fitness is a central concept in evolutionary biology, but there is no unified definition. We review recent theoretical developments showing that including fluctuating environments and density dependence has important implications for how differences among phenotypes in their contributions to future generations should be quantified. The rate of phenotypic evolution will vary through time because of environmental stochasticity. Density dependence may produce fluctuating selection for large growth rates at low densities but for larger carrying capacities when population sizes are large. In general, including ecologically realistic assumptions when defining the concept of fitness is crucial for estimating the potential of evolutionary rescue of populations affected by environmental perturbations such as climate change.
authors.affiliation: Department of Biology, Centre for Biodiversity Dynamics, Norwegian University of Science and Technology, 7491 Trondheim, Norway. Electronic address: Bernt-Erik.Sather@bio.ntnu.no.
authors.forename: Bernt-Erik
authors.initials: BE
authors.lastname: Sæther
authors.affiliation: Department of Mathematical Sciences, Centre for Biodiversity Dynamics, Norwegian University of Science and Technology, 7491 Trondheim, Norway.
authors.forename: Steinar
authors.initials: S
authors.lastname: Engen
mesh_terms: D000220:Adaptation, Biological; D005075:Biological Evolution; D004777:Environment; D056084:Genetic Fitness; D008962:Models, Theoretical; D010641:Phenotype; D011156:Population Density; D012641:Selection, Genetic; D013269:Stochastic Processes
keywords: bet-hedging; environmental stochasticity; fitness; phenotypic evolution; selection