نتایج جستجو برای: clinal variation
تعداد نتایج: 296685 فیلتر نتایج به سال:
The North Atlantic intertidal community provides a rich set of organismal and environmental material for the study of ecological genetics. Clearly defined environmental gradients exist at multiple spatial scales: there are broad latitudinal trends in temperature, meso-scale changes in salinity along estuaries, and smaller scale gradients in desiccation and temperature spanning the intertidal ra...
Clinal patterns of autosomal genetic diversity within Europe have been interpreted in previous studies in terms of a Neolithic demic diffusion model for the spread of agriculture; in contrast, studies using mtDNA have traced many founding lineages to the Paleolithic and have not shown strongly clinal variation. We have used 11 human Y-chromosomal biallelic polymorphisms, defining 10 haplogroups...
The hybrid zone on Mount Etna (Sicily) between Senecio aethnensis and Senecio chrysanthemifolius (two morphologically and physiologically distinct species) is a classic example of an altitudinal cline. Hybridization at intermediate altitudes and gradients in phenotypic and life-history traits occur along altitudinal transects of the volcano. The cline is considered to be a good example of ecolo...
BACKGROUND AND AIMS This study sought genetic evidence of long-term isolation in populations of Monstera adansonii var. klotzschiana (Araceae), a herbaceous, probably outbreeding, humid forest hemi-epiphyte, in the brejo forests of Ceará (north-east Brazil), and clarification of their relationships with populations in Amazonia and the Atlantic forest of Brazil. METHODS Within-population genet...
Sexual selection, more so than natural selection, is posited as the major cause of sex differences. Here I show ecological correlations between solar radiation levels and sexual dimorphism in body color of a Hawaiian damselfly. Megalagrion calliphya exhibits sexual monomorphism at high elevations, where both sexes are red in color; sexual dimorphism at low elevations, where females are green; a...
Abstract Determining the factors responsible for phenotypic variation within species is a fundamental task in evolutionary ecology. Isolation by distance, isolation environment and clines along secondary contact zones between formerly isolated populations are common patterns of morphological variation. In this study, we evaluated whether exhibit association with or Manacus manacus contrasting p...
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