Evolution in Peripheral Isolated Populations: Carpodacus Finches on the California Islands

Power, Dennis M.

doi:10.2307/2407649

Cited by 22 publications

(2 citation statements)

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“…Similar discordance between patterns of similarity in covariance matrices and geographic or phylogenetic relationships among taxa was found in several other studies (Riska 1985;Lofsvold 1986;Kohn and Atchley 1988;Cheverud 1989;Wagner 1990;Steppan 1997). Such divergence in covariance patterns among populations is most consistent with diverse responses to local fluctuating selection pressures (Riska 1985;Arnold 1992), especially in peripheral populations that are subject to frequent variation in population density (Felsenstein 1976; see also Power 1979).…”

Section: Discussionsupporting

confidence: 81%

The Evolution of Sexual Dimorphism in the House Finch. I. Population Divergence in Morphological Covariance Structure

Badyaev

Hill

2000

Evolution

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Abstract. Patterns of genetic variation and covariation strongly affect the rate and direction of evolutionary change by limiting the amount and form of genetic variation available to natural selection. We studied evolution of morphological variance-covariance structure among seven populations of house finches (Carpodacus mexicanus) with a known phylogenetic history. We examined the relationship between within-and among-population covariance structure and, in particular, tested the concordance between hierarchical changes in morphological variance-covariance structure and phylogenetic history of this species. We found that among-population morphological divergence in either males or females did not follow the within-population covariance patterns. Hierarchical patterns of similarity in morphological covariance matrices were not congruent with a priori defined historical pattern of population divergence. Both of these results point to the lack of proportionality in morphological covariance structure of finch populations, suggesting that random drift alone is unlikely to account for observed divergence. Furthermore, drift alone cannot explain the sex differences in within-and among-population covariance patterns or sex-specific patterns of evolution of covariance structure. Our results suggest that extensive among-population variation in sexual dimorphism in morphological covariance structure was produced by population differences in local selection pressures acting on each sex.Key words. Carpodacus mexicanus, genetic correlation, phenotypic covariance, sexual size dimorphism.Received November 1, 1999. Accepted April 2, 2000.Patterns of genetic variation and covariation strongly affect the rate and direction of evolutionary change (Lande 1976(Lande , 1980Lande and Arnold 1983). Although genetic variancecovariance structure (hereafter covariance structure) that results from developmental or functional interrelationships among traits may be adaptive when it is formed (Berg 1960;Cheverud 1984;Wagner 1988), it can bias evolutionary change in response to new environments (e.g., Maynard Smith et al. 1985;Arnold 1992).Two issues related to covariance structure of populations are of a particular interest to studies of evolution: the relative temporal constancy of genetic covariances and the relationship between phenotypic and genetic covariance structures (Lande 1980(Lande , 1985Turelli 1988). Genetic covariance structure may remain constant during the initial periods of taxa divergence, but eventually it is expected to evolve under selection or drift (e.g., Lande 1980Lande , 1985Zeng 1988;Schluter 1996). Indeed, theoretical and empirical studies have suggested that genetic correlations can strongly bias short-term evolution, but their importance should diminish over time (Cheverud 1984;Lofsvold 1986Lofsvold , 1988Turelli 1988;Zeng 1988;Shaw et al. 1995;Schluter 1996) especially when the correlations themselves are the subject of selection (e.g., Berg 1960; Wilkinson et al. 1990), and constancy of genetic covariance patte...

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Section: Discussionsupporting

confidence: 81%

The Evolution of Sexual Dimorphism in the House Finch. I. Population Divergence in Morphological Covariance Structure

Badyaev

Hill

2000

Evolution

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“…It is well known that insular populations often differentiate rapidly. A recent study by Power (1979) has shown that greater divergence of house finch populations is found for California islands than for the adjacent mainland. However, this study also illustrates the difficulties of assessing the importance of isolation in archipelagic differentiation.…”

Section: Riverine Barriers and Differentiationmentioning

confidence: 98%

Riverine Barriers to Gene Flow and the Differentiation of Fence Lizard Populations

Pounds¹,

Jackson²

1981

Evolution

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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Society for the Study of Evolution is collaborating with JSTOR to digitize, preserve and extend access to Evolution. Even prior to the advent of population genetics, it was held that the exchange of genes among populations retards differentiation and promotes the cohesiveness of species. Jordan (1905) maintained that the characters of a species remain "substantially uniform" if free movement of individuals is possible. This concept of a conservative evolutionary factor became a fundamental component of the synthetic theory of evolution (Dobzhansky, 1937; Mayr, 1942). Ehrlich and Raven (1969), questioning the validity of the traditional view, suggested that gene flow may play an inconsequential role in the cohesion of populations. Instead of stimulating research, this paper was the provenance of an influential viewpoint that relegates gene flow to a lower echelon of evolutionary factors. For example, Emmel (1976) wrote, "It therefore became apparent by the late 1960's that gene flow between populations seems to have little to do with holding species together as similar phenotypic units . . . . " We have contended that this neo-orthodoxy lacks an empirical base (Jackson and Pounds, 1979). The present empirical study focuses on the effect of gene flow on the divergence of neighboring demes. Theoretically, parapatric differentiation can occur (Jain and Bradshaw, 1966; Endler, 1973, 1977), and laboratory experiments have confirmed this (e.g., Endler, 1973, 1977). However, as laboratory and computer models often assume conditions not found in nature, examination of natural situations is imperative. Well-documented instances of natural parapatric 1 Present address: Department of Zoology, University of Florida, Gainesville, Florida 32611. LITERATURE CITED ANTONOVICS, J. 1971. The effects of a heterogeneous environment on the genetics of natural populations. Amer. Sci. 59:593-599. ATCHLEY, W. R., AND D. ANDERSON. 1978. Ratios and the statistical analysis of biological data.

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A Red Bird in a Brown Bag

Hill

2002

245

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The House Finch is among the most mundane birds, so ubiquitous and familiar across the U.S. and Canada that it does not rate a glance from most bird enthusiasts. But males have carotenoid-based plumage coloration that varies markedly among individuals, making the House Finch a model species for studies of the function and evolution of colorful plumage. In more depth and detail than has been attempted for any species of bird, this book takes a tour of the hows and whys of ornamental plumage coloration. The book begins by reviewing the history of the study of colorful plumage, which began in earnest with the debates of Darwin and Wallace but which was largely forgotten by the middle of the 20th century. Documenting the extensive plumage variation among males both within and between populations of House Finches, the book explores the mechanisms behind plumage variation and looks at the fitness consequences of condition-dependent ornament display for both males and females. The book concludes by examining the processes by which carotenoid-based ornamental coloration may have evolved.

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Evolution in Peripheral Isolated Populations: Carpodacus Finches on the California Islands

Cited by 22 publications

References 10 publications

The Evolution of Sexual Dimorphism in the House Finch. I. Population Divergence in Morphological Covariance Structure

The Evolution of Sexual Dimorphism in the House Finch. I. Population Divergence in Morphological Covariance Structure

Riverine Barriers to Gene Flow and the Differentiation of Fence Lizard Populations

A Red Bird in a Brown Bag

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