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Defining fitness in evolutionary models.

¹Department of Biology, University of California, Riverside, CA 92521, USA. Derek.roff@ucr.edu

Journal of Genetics

|January 17, 2009

Summary

Defining fitness in evolutionary models is crucial. This review clarifies fitness definitions across five key dimensions, recommending the invasion exponent for complex models, especially those with density-dependence or frequency-dependence.

Area of Science:

Evolutionary Biology
Theoretical Ecology
Mathematical Modeling

Background:

Accurate fitness definition is essential for analyzing evolutionary models.
Existing definitions may be insufficient when complex ecological factors are involved.

Purpose of the Study:

To review and clarify fitness definitions in evolutionary models.
To relate fitness definitions to five major model dimensions: population size, environment, density-dependence, population dynamics, and frequency-dependence.

Main Methods:

Literature review of fitness definitions in evolutionary modeling.
Analysis of how different model characteristics necessitate specific fitness measures.
Comparison of Malthusian parameter (r) and net reproductive rate (R(0)) with the invasion exponent.

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Main Results:

Simple models may use Malthusian parameter (r) or net reproductive rate (R(0)).
Density-dependence and complex population dynamics require the use of the invasion exponent.
Social environments and frequency-dependence present unique challenges for fitness definition.

Conclusions:

The choice of fitness definition must align with the complexity of the evolutionary model.
The invasion exponent is a more robust measure for advanced models.
Further consideration is needed for fitness in social and frequency-dependent contexts.