Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 22 for “"barriers to gene flow"”.
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Genetic Structure of Yonahlossee Salamander Populations.
… populations of the yonahlossee are considered to be rare and local throughout their range. Genetic differentiation among populations of any species is usually attributable to long-standing, extrinsic barriers to gene flow. Because of their disjunct population structure and some observed …
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Phylogeography of Darlingtonea Kentuckensis and Molecular Systematics of Kentucky Cave Trechines
<p>The monotypic cave carabid genus Darlingtonea is widely distributed along the eastern band of the Mississippian/Pennyroyal plateau in Kentucky and northern Tennessee. DNA sequence data from the mitochondrial gene cytochrome oxidase subunit I (COI) was collected from one to four individuals from …
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Genetic structure and disease prevalence of boreal toads (Bufo boreas) in Glacier National Park
… The causes of most declines are not well understood, though many declines have been linked to the emerging infectious disease chytridiomycosis. Additionally, amphibians are physiologically constrained to moist habitats and considered poor dispersers; thus, they may suffer genetic consequences of …
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Genetic structure and disease prevalence of boreal toads (Bufo boreas) in Glacier National Park
… The causes of most declines are not well understood, though many declines have been linked to the emerging infectious disease chytridiomycosis. Additionally, amphibians are physiologically constrained to moist habitats and considered poor dispersers; thus, they may suffer genetic consequences of …
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Phylogeography of the Night Lizard, Xantusia henshawi, from Southern California
… States and northern Baja California, Mexico. Generally, little morphological variation is seen in this species over a variety of habitats throughout its range, from elevations near sea level to approximately 2000 meters, and from Mediterranean habitats near the Pacific coast to arid desert …
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Exploring Patterns of Genetic Diversity of a Malagasy Ant Species: Anochetus Madagascarensis
… is extremely diverse and imperiled. Close to 90% of all land dwelling species are endemic to Madagascar (plants, reptiles, mammals and amphibians). Understanding patterns of genetic diversity for species can aid in better conservation efforts. In this study, I focus on the endemic Malagasy …
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Nested clade analysis of geographic structure in the morphologically variable Themeda triandra in South Africa
… in recent years with the use of chloroplast DNA to detect sufficient intraspecific variation to reach significant conclusions about plant species histories, both temporally and spatially. In this study, the geographic structure and possible origin of the morphologically variable Themeda triandra …
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Illuminating the Drivers of Genomic Diversification in Lamprologine Cichlids of the Lower Congo River
… of the earth’s surface. Rivers connect heterogeneous habitats in a linear form and provide excellent simplified models to understand how aquatic biodiversity evolves. In particular, the lower Congo River (LCR) in west Central Africa consists of a dynamic hydroscape exhibiting extraordinary …
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Host use, mutualism and parasitism in the Lycaeides butterfly complex
… in host use in herbivorous insects can lead to diversification, speciation, and changes in other ecological interactions. In the first chapter, larval performance was investigated in three species of Lycaeides butterflies and placed into the context of other already studied ecological traits …
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Looking into the Past: The Diversification of Amphibians in the Neotropical Savannas
… the evolutionary processes that contributed to biotic diversification in the Cerrado savanna using amphibians as a model. Evolutionary patterns were investigated by comparing the phylogeographic and biogeographic history of biome-specific yet widely distributed amphibian species …
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Diet, adaptation and the evolution of assortative mating in Ceratitis capitata
… The action of natural selection in establishing barriers to gene flow between populations, or reproductive isolation, is increasingly understood to be a primary driver of speciation and thus biodiversity. ‘Ecological speciation’ is now supported by evidence from numerous studies in a range of …
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The Evolutionary History and Phylogeny of the Lithodinae (Decapoda: Anomura: Lithodidae)
… since the<br/>modern syntheses of plate tectonics, oceanography, species theory and cladistic<br/>systematics. The focus of this thesis was to investigate the origin and radiations of the<br/>deep-sea Lithodinae as a case study for interchanges between deep and shallow oceans<br/>in mobile …
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Macrogeographic Genetic Structure in Acanthephyra curtirostris (Oplophoridae)
… space on our planet is occupied by zooplankton species long assumed to be widespread and genetically undifferentiated across their species range. Recently, however, data from sensitive DNA-based molecular markers has shown that many cryptic species exist in the sea and that marine …
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Microgeographic divergence in a single-island endemic: evolutionary patterns and conservation implications
Understanding the processes that generate biological diversity is the central goal of evolutionary biology. Geographic isolation has traditionally been viewed as the primary scenario favoring evolutionary divergence. However, there is growing appreciation for the role of ecological variation and …
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Effects of Impoundments on the Community Assemblage and Gene Flow of Stream Crayfishes
… changes biological assemblages and creates barriers to gene flow. While changes in species assemblages and gene flow have been assessed for numerous impoundments and stream organisms, no study has assessed the effects of large impoundments on crayfish assemblages and population genetic …
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Ecology of northern long-eared bats (Myotis septentrionalis) in a coastal setting after the introduction of White-nose Syndrome
… have declined sharply in recent years due to the introduction and rapid spread of White-nose Syndrome. This has prompted an urgent need for a greater understanding of their natural history in order to support the conservation of extant populations, particularly where forested day-roost and …
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Habitat modification and gene flow in Saimiri oerstedii: Landscape genetics, intraspecific molecular systematics, and conservation
… fragmentation, often results in the loss of genetic diversity due to reduced gene flow, inbreeding, and genetic drift. However, the severity of these effects depends on how diminished dispersal and gene flow become between patches of suitable habitat. An empirical understanding of how habitat …
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Conservation and population genetics of African and Asian rhinoceros
… (Diceros bicornis), white rhinoceros (Ceratotherium simum), Indian rhinoceros (Rhinoceros unicornis), Javan rhinoceros (Rhinoceros sondaicus) and Sumatran rhinoceros (Dicerorhinus sumatrensis). Anthropogenic activities, such as poaching and habitat disruption, have led to steep declines in …
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Hiding in plain sight: unveiling cryptic diversity and patterns in bumble bees
Bumble bee research has a rich history that spans more than three centuries. The distributions and the vibrant color patterns of nearly all species of bumble bees are well mapped and described. In addition, the natural history, colony structure and social behavior of bumble bees are well documented …
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Invasion Routes and Evolution of Brook Stickleback (Culaea inconstans) in Eastern Washington
… 1. Invasive species pose a serious threat to native ecosystems. In eastern Washington brook stickleback (Culaea inconstans) is an important invasive species, especially at Turnbull National Wildlife Refuge, where they compete with waterfowl for food resources and are associated with …
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