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 16 of 16 for “"species concepts"”.
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A biosystematic study of the rare plant <i>Paronychia virginica</i> Sprengel (Caryophyllaceae) employing morphometric and allozyme analyses
… values reported for seed plants, widespread species, and endemic species. Hierarchical F statistics suggest higher levels of genetic variability within individual populations than among populations, regardless of geographic location. All statistically significant (P < 0.05) deviations from …
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Species limits in the Rhodocoma gigantea (Kunth) Linder complex
… been recognised by earlier authors as separate species on the basis of perianth length and shape. Linder (1985) superficially lumped these two species under Rhodocoma gigantea arguing that the difference between the two appear to be brought by ecological gradient. Numerical phenetic analyses of …
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Biosystematic Studies in Crepidotus and the Crepidotaceae (Basidiomycetes, Agaricales)
… either a germ pore or plage. The majority of species belong to Crepidotus, distinguished by their pleurotoid basidiomata. Because of their diverse morphology, the presence of several conflicting classifications, and lack of data regarding the biology, phenotypic plasticity, or phylogeny of …
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Species limits in Cannomois virgata complex (Restionaceae)
… analysis. The clusters correspond to three species proposed under the operational definition, which recognises species from differentiated clusters in phenetic space whose distinctness was assumed to be the manifestation of underlying fixed and qualitative differences following speciation. …
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The systematics and ecology of Boletes with special reference to the Genus Suillus and its ectomycorrhizal relationships in Nepal
The Suillus mycota of Nepal was studied. Nine species are recognized and described; five of the nine appear to be new species. Additional species were collected, but material was inadequate to describe them completely. Cultures of eight and synthesized ectomycorrhizae of six of the Suillus species …
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Phylogeny and biogeography of the toxic dinoflagellate Alexandrium
… traits traditionally used to identify and group species, although other traits appeared phylogenetic ally conserved. The ability to produce toxins has been acquired and/or lost multiple times during Alexandrium evolution. Because most PSP events are caused by either the tamarensis or minutum …
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Shifts in Myxomycete Community Structure in Selected Microhabitats Across Nutrient Treatments in a Lowland Tropical Forest of Panama
… with two major contributions. Identifying species is a fundamental step toward characterizing the diversity of a community. Given the unique challenge of identifying species of myxomycetes imposed by their unique biology, this dissertation begins in chapter two with a review of the …
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Phylogenies of the sunbirds, spiderhunters and flowerpeckers (Nectariniidae) based on analyses of vocalisations
… from the perspectives of both the biological species and phylogenetic species concepts. This study constructed phylogenies for the Nectariniidae from up to 20 parameters derived from quantitative analyses of their vocalisations and used these to test hypotheses on whether or not the origin of …
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Genetic diversity and structure of calanoid copepods: Molecular evolutionary patterns in coastal estuaries (Acartia tonsa) and the open ocean (Calanus spp)
… share a conserved morphology that complicates species identification. A primary focus of this study was the genetic and physiological variation of the calanoid copepod Acartia tonsa from four estuaries along the East Coast of the USA (Great Bay, NH, Buzzards Bay, MA, Narragansett Bay, RI, and …
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Metodi molecolari nello studio della variabilità genetica di Tuber borchii
… indicate that there are likely to be two cryptic species within the T. borchii population sampled. Our results suggest that isolation between populations of T. borchii could have led to reproductive isolation between two lineages. This isolation is likely due to sympatric speciation caused by a …
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Systematics and evolutionary ecology of Osteospermum section Polygalinae DC
Osteospermum L. (Asteraceae) is a genus of ca. 80 species of mainly yellow-flowered annual and perennial daisies, having most of its diversity in the Greater Cape Floristic Region of South Africa. The genus is characterised by remarkable variation in fruit structure and dispersal biology, …
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Systematics of Hermannia L. (Malvaceae): a taxonomic review of the genus
… predominantly found in South Africa. While four species occur within North and Central America and one species in Australia, most species are distributed across Africa from Cape Verde eastwards to Saudi Arabia, with the majority restricted to Southern Africa. The taxonomy of the genus is not well …
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Advancing the use of evolutionary considerations in spatial conservation planning
… planning remain rare, with metrics such as species richness (which ignore differences in evolutionary distinctiveness between species) more often used. This work aims to address this by focusing on the inclusion of phylogenetic diversity (PD), which measures evolutionary diversity by summing …
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Population structure and genetic variation in Hector’s dolphin (Cephalorhynchus hectori)
… origins and taxonomic status of this species. A high-resolution genetic analysis of population structure was considered important for the determination of population boundaries and delimitation of conservation management units due to potentially unsustainable fisheries-related …