A multivariate study of geographic variation in the whelk Dicathais

Phillips, Bruce F.; Campbell, N. A.; Wilson, Barry

doi:10.1016/0022-0981(73)90017-8

Cited by 77 publications

(32 citation statements)

References 22 publications

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“…Many studies have found a genetic component to morphological variation in gastropods, particularly in the case of discrete characters, such as color and pattern (e.g., Cain et al 1960;Atkinson and Warwick 1983;Palmer 1984Palmer , 1985a. Control of variation in continuous morphological characters, such as shape, is less well understood, although there is evidence for both plastic (Phillips et al 1973;Kemp and Bertness 1984;Boulding and Hay 1993;Gibbs 1993) and genetic (Newkirk and Doyle 1975;Crothers 1980;Palmer 1985b;Johannesson and Johannesson 1996; Parsons 1997) components of variation.…”

Section: Discussionmentioning

confidence: 99%

Ecological Opportunity in Adaptive Radiation of Galápagos Endemic Land Snails

Parent

Crespí

2009

The American Naturalist

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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.. abstract: The classic evolutionary hypothesis of ecological opportunity proposes that both heterogeneity of resources and freedom from enemies promote phenotypic divergence as a response to increased niche availability. Although phenotypic divergence and speciation have often been inferred to be the primary consequences of the release from competition or predation that accompanies a shift to a new adaptive zone, increased phenotypic variation within species is expected to represent the first stage resulting from such a shift. Using measures of intraspecific morphological variation of 30 species of Galápagos endemic land snails in a phylogenetically controlled framework, we show that the number of local congeners and the number of local plant species are associated with lower and higher intraspecific phenotypic variation, respectively. In this clade, ecological opportunity thus explicitly links the role of competition from congeners and the heterogeneity of resources to the extent of intraspecific phenotypic divergence as adaptive radiation proceeds.

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Section: Discussionmentioning

confidence: 99%

Ecological Opportunity in Adaptive Radiation of Galápagos Endemic Land Snails

Parent

Crespí

2009

The American Naturalist

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“…The variables were transformed as in Jordan et al (1993) to optimize population normality and remove the correlation between population means and variances. Multivariate analyses of the three subspecies (bicostata, globulus, and pseudoglobulus) were undertaken using canonical variate analysis (CVA; Phillips et al 1973), an ordination technique that maximizes differences between defined groups relative to within-group variation. The Jeeralang and other intergrade individuals were placed within the multivariate discriminant space defined by the three subspecies.…”

Section: Morphometric Methodsmentioning

confidence: 99%

Microsatellite and morphological analysis ofEucalyptus globuluspopulations

Jones¹,

Steane²,

Potts³

et al. 2002

Can. J. For. Res.

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Eucalyptus globulus Labill. is native to southeastern Australia and is the most important temperate hardwood plantation species in the world. It consists of four subspecies that are morphologically and geographically distinct but that are linked by morphologically and geographically intermediate populations. The Jeeralang provenance, an intermediate population from southeastern Victoria, is an important source of seed for plantations and genetic material for breeding programs because of its superior growth and wood density. To determine the genetic affinities of this provenance, 154 trees from three subspecies and the Jeeralang provenance were sampled. Analysis of 12 morphological characters verified that the Jeeralang provenance is intermediate between subspecies bicostata (Maiden, Blakely, & J. Simm.) Kirkpatr., globulus and pseudoglobulus (Naudin ex Maiden) Kirkpatr., with individuals having closest affinities to either ssp. globulus or ssp. bicostata. However, eight microsatellite loci showed that the Jeeralang provenance has greater affinities to Victorian ssp. globulus to which it is geographically closest. In contrast, Tasmanian and Victorian ssp. globulus are morphologically similar yet appear to be distinct at the molecular level. This study emphasizes the importance of using traits that are unlikely to be influenced by selection when determining the origin and affinities of populations.Résumé : Eucalyptus globulus Labill. est une espèce indigène du sud-est de l'Australie. C'est la plus importante espèce feuillue en plantation au monde. L'espèce est constituée de quatre sous-espèces qui sont morphologiquement et géographiquement distinctes. Cependant, ces sous-espèces sont liées entre elles par des populations morphologiquement et géographiquement intermédiaires. La provenance Jeeralang, une population intermédiaire de la région sud-est de Victoria, représente une source importante de semences pour l'établissement de plantations, en plus de fournir du maté-riel génétique pour les programmes d'amélioration, en raison de sa supériorité pour la croissance et la densité du bois. Afin de déterminer les affinités génétiques de cette provenance, 154 arbres représentatifs de trois sous-espèces et de la provenance Jeeralang ont été échantillonnés. La caractérisation de 12 caractères morphologiques a permis de confirmer que la provenance Jeeralang était intermédiaire entre sous-espèces bicostata (Maiden, Blakely & J. Simm.) Kirkpatr., globulus et pseudoglobulus (Naudin ex Maiden) Kirkpatr. Les individus de cette provenance avaient plus d'affinités avec ssp. globulus et ssp. bicostata. Cependant, l'analyse de huit loci de microsatellites a révélé que la provenance Jeeralang avait le plus d'affinités avec la sous-espèce globulus de la région de Victoria, dont elle est géographiquement la plus rapprochée. À l'opposé, les individus de la sous-espèce globulus des régions de Tasmanie et de Victoria étaient morphologiquement similaires même s'ils étaient distincts à l'échelle moléculaire. Cette étude souligne ...

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“…Populations were classified using average linkage clustering (Sneath and Sokal 1973) of these mean scores. The distances between populations are thus Mahalanobis' distances (Phillips et al 1973). The variation within each population within the two-dimensional space discriminating subspecies was calculated as the variance of the euclidean distances of individuals from the group centroid.…”

Section: Statistical Analysesmentioning

confidence: 99%

Variation in the Eucalyptus globulus Complex Revisited

Jordan¹,

Potts²,

Kirkpatrick³

et al. 1993

Aust. J. Bot.

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Patterns of variation in the Eucalyptus globulus Labill. complex are reassessed by combining capsule measurements from an earlier study with recent collections, mainly of subspecies globulus. Four groups of populations are apparent and can be ascribed to the four subspecies maidenii, pseudoglobulus, bicostata and globulus. Intergrade populations between the latter three subspecies are widespread and mainly occur in the Otway Ranges and west Gippsland. There is a continuum in capsule morphology between the three-fruited subspecies, pseudoglobulus and bicostata. Subspecies globulus intergrades with these three-fruited intermediates. Three-fruited intergrade populations occuning north and south of the range of core pseudoglobulus can be differentiated and probably represent intergrades between pseudoglob~rlus and bicostata and between pseudoglobulus and globul~is respectively. Reports of bicostata in the Furneaux Group and southern Victoria are thus probably erroneous and result from convergence in capsule morphology. The previously described taxon E. stjohnii (R. T. Bak.) R. T. Bak. is part of the continuum between subspecies pseudoglobulus and bicostata, but closer to pseudoglobulus. Populations phenotypically intermediate between and significantly different from globulus and the three-fruited intergrades are highly variable and occur in western Tasmania, on the northern end of Flinders Island, in the Otway Ranges and in west Gippsland. An isolated population on Rodondo Island is highly variable and has closest affinities to pseudoglobulus despite being within the geographical range of core globulus. The population from King Island is intermediate between the Otway phenotype and core globulus. The climatic regimes of the subspecies are markedly different and most three-fruited and globul~cs intergrade populations have closer climatic affinities to pseudoglobulus and globulus respectively. Hypotheses relating to the origin of the pattern of variation in E. globulus are discussed.

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A multivariate study of geographic variation in the whelk Dicathais

Cited by 77 publications

References 22 publications

Ecological Opportunity in Adaptive Radiation of Galápagos Endemic Land Snails

Ecological Opportunity in Adaptive Radiation of Galápagos Endemic Land Snails

Microsatellite and morphological analysis ofEucalyptus globuluspopulations

Variation in the Eucalyptus globulus Complex Revisited

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