The Confusions of Fitness

Abstract

The central point of this essay is to demonstrate the incommensurability of 'Darwinian fitness' with the numeric values associated with reproductive rates used in population genetics. While sometimes both are called 'fitness', they are distinct concepts coming from distinct explanatory schemes. Further, we try to outline a possible answer to the following question: from the natural properties of organisms and a knowledge of their environment, can we construct an algorithm for a particular kind of organismic lifehistory pattern that itself will allow us to predict whether a type in the population will increase or decrease relative to other types? 1 Introduction 2 Darwinian fitness 3 Reproductive fitness and genetical models of evolution 4 The models of reproductive fitness 4.1 The Standard Viability Model 4.2 Frequency-dependent selection 4.3 Fertility models 4.4 Overlapping generations 5 Fitness as outcome 5.1 Fitness as actual increase in type 5.2 Fitness as expected increase in type 5.2.1 Expected increase within a generation 5.2.2 Expected increase between generations 5.2.3 Postponed reproductive fitness effects 6 The book-keeping problem 7 Conclusion We would like to thank

The early history of chance in evolution

“…On the one side, we have "causalists," who argue that natural selection and genetic drift describe causally efficacious processes (e.g., Brandon, 1978;Mills and Beatty, 1979;Hodge, 1987;Stephens, 2004;Ramsey, 2006;Abrams, 2009;Otsuka et al, 2011). They are opposed by the "statisticalists," who claim on the contrary that these theories are merely statistical summaries of genuinely causal events at the level of the individual organism (e.g., Matthen and Ariew, 2002;Walsh et al, 2002;Ariew and Lewontin, 2004;Krimbas, 2004;Walsh, 2007;Ariew and Ernst, 2009;Walsh, 2010).…”

Hamiltonian inclusive fitness: a fitter fitness concept

“…Disagreement over the definition of fitness and the mode of action of natural selection persists [3][4][5][6]. My purpose is not to review fitness concepts or their history, but to provide a general overview of inclusive fitness within the broader fitness concept framework.…”

A critical review of the statisticalist debate

“…It is well known that in frequency-dependent selection the fitness of an individual organism depends on population-level parameters such as the population size or genetic/phenotypic frequencies (Ariew and Lewontin, 2004;Ariew and Ernst, 2009). Gillespie (1974), for example, has shown that when a population consists of two genotypes that produce offspring at different variances, the evolutionary trajectory is affected by the population size.…”