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 32 for “"Species delimitation"”.
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Systematics and Species Delimitation in New Guinea Skink Species Complexes (Squamata: Scincidae)
… topics in systematic and evolutionary biology, species are a fundamental unit in biology, and are utilized by and critical to a wide variety of studies in the life sciences. Despite this importance, little work has focused on developing and examining objective methods for species delimitation …
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A contribution to species delimitation and taxonomy of North American Entomobrya (Collembola: Entomobryidae)
… of DNA sequence divergence among congeneric species suggest that circumscription of species based solely on traditional morphological and color pattern characters provide a very conservative estimate of actual species diversity. Many described species in the genera Orchesella, Isotomurus and …
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Cryptobenthic Coral Reef Fishes: Resolving Critical Gaps in Species Delimitation, Sampling Techniques, and Phylogenetic relationships
… coral reefs but represent about 40% of the fish species and about 50% of fish abundance in coral reef ecosystems. Their diversity can be explained by their extremely limited dispersal abilities and short generation times (promoting allopatric speciation) coupled with their ability to partition …
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Species delimitation and speciation process in the Seriphium plumosum L. complex (Gnaphalieae: Asteraceae) in South Africa
… key areas: first, to what extent has the true species richness of the Cape been discovered and described, and second, what are the key drivers of speciation? Steady efforts in taxonomy dating back to the early 17th century have led some to estimate that over 99% of species in the Cape flora …
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How reliable is morphological species delimitation in kelp? : a study of two closely related South African Ecklonia species
… Zealand. Genetically they exist as two distinct species and can usually be differentiated morphologically, especially when occurring as geographically separate entities. However, they do appear to intergrade when growing together, where plants of apparent intermediate and indeterminate morphology …
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Phylogenetic revision of the genus Cherokia (Chamberlin, 1949) (Polydesmida: Xystodesmidae)
… family Xystodesmidae (Polydesmida) includes 521 species with a center of diversity concentrated in the Appalachian Mountains. Within this family, the genus Cherokia, a monotypic taxon with the type species Cherokia georgiana, is divided into three subspecies. The last revision of this genus was …
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Under the trapdoor - resolving the taxonomy and phylogeography of the trapdoor spider genus Stasimopus (Mygalomorphae: Stasimopidae) of the Karoo
… This study was undertaken to understand the true species diversity and history of this genus in the Karoo region of South Africa. The Karoo is a semi-arid, unique and sensitive ecosystem which is facing pressure for development due to economic incentives. This area has long been neglected, with …
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Speciation and diversification of the beetle tribe Cratopini on the islands of the South West Indian Ocean area.
… range from aspects of the ecology of individual species to the relationships within islands amongst morphospecies and finally to the biogeography of the group as a whole. Throughout, where appropriate, reference is made to the current understanding of Indian Ocean geology and how this effects the …
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Phylogenetic relationship of forest spiny pocket mice (Genus Heteromys) inferred from mitochondrial and nuclear markers with implications for species boundaries
… of taxonomic groups and to aid in the delimitation of new species. I generated and analyzed sequence data for forest spiny pocket mice (Genus <em>Heteromys</em>) for the mitochondrial gene cyt <em>b</em> (1143 bp) and two nuclear gene segments MYH2 (252 bp) and EN2 (189 bp). I used …
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GENOMICS FOR WILD AND MEDICINAL PLANT DIVERSITY STUDIES
… genomic resources for non-model, medicinal plant species in order to facilitate research in biodiversity genomics, flower development, and genetic improvement, focusing on two plant species: Salvia pratensis and Althaea officinalis. In one part of the project, a good quality, annotated genome …
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Pilot-scale production and physicochemical properties of mycelium-based materials and diversity assessment of a fungal biobank
… locally sourced wild fungal cultures in terms of species diversity to inform future testing for mycelium-based material production. Species boundaries were delineated using ITS sequences, providing a foundation for identifying strains with desirable traits such as rapid growth and environmental …
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Elucidating cryptic diversity in East African frogs : the case of Arthroleptis francei Loveridge, 1953
Detailed information on the diversity of species and their distributions is crucial for the implementation of useful conservation measures. Here, I focus on the Afromontane region of Malawi and Mozambique, and use molecular techniques, environmental inferences and species delimitation methods to …
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Looking into the Past: The Diversification of Amphibians in the Neotropical Savannas
… biome-specific yet widely distributed amphibian species (<em>Chiasmocleis albopunctata, Dendropsophus rubicundulus</em> and <em>Physalaemus nattereri</em>). Location: Cerrado region, central South America. Methods: I sampled thousands of loci randomly distributed throughout the genomes of all …
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A Phylogenetic History of the Tenerife Skink Chalcides viridanus: A multi-locus Coalescent Approach
… questions about population history of this species. Specifically, using previously unused nuclear gene markers to obtain a more robust phylogeographical history of the species, using new techniques to estimate whether any historic changes in population size can be linked to known geological …
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Model-based approaches to discovering diversity : new implementations, tests of adequacy and an empirical application to central American Diptera
… of the GMYC, a statistical model used for species delimitation. This implementation fully accounts for uncertainty in model parameters, and we test its performance under various historical scenarios. We find that the model generally performs well, but that failing to account for uncertainty …
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Pseudoscorpion Systematics & Phylogenetics: Exploring the Effects of Accelerated Rates of Evolution on Both Ancient and Recent Diversification
… 4,359 currently described extant pseudoscorpion species in 26 families, distributed across virtually all terrestrial habitats on Earth (except for the polar regions). Given their general ubiquity, these tiny animals (~2–8 mm) largely go unnoticed by humans, inhabiting cryptic microhabitats like …
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Adaptive radiation and speciation in African weakly-electric fish
… owing to their ability to communicate through species-specific Electric Organ Discharges (EODs) produced by a novel, muscle-derived electric organ. Indeed, such EODs might have acted as effective pre-zygotic isolation mechanisms, hence favoring ecological speciation in this group of fishes. …
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Biodiversity, conservation and mimicry rings of Appalachian millipedes
… including many endemic and range-restricted species. Millipedes have extremely low dispersal capacity, strict environmental requirements for survival and, in the case of the family Xystodesmidae, are completely blind. Coupled with the complex topology of the Appalachians, xystodesmid …
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Integrative approach to discovering species diversity within the Mediterranean group of the Bemisia tabaci complex
Bemisia tabaci is a complex of cryptic whitefly species, which includes some of the world’s most damaging agricultural pests. The Mediterranean (MED) putative species is globally invasive and its populations are often resistant to insecticides. The intra-species genetic variability identified in …
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