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 50 for “"species boundaries"”.
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Across the great divide : chimeras and species boundaries
… early 1980s, scientists have been creating cross-species chimeras, first combining mouse species that could not interbreed naturally, then moving on to create chimeras from even more distantly related animals such as sheep and goats. Scientists use chimeras to study fundamental processes of life …
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A re-assessment of the species boundaries in Merciera A.DC.
… in the genus Merciera A.DC. to re-assess the species boundaries. This study differs from previous studies in the genus because it employs multivariate statistical methods. Vegetative and floral characters obtained from herbarium specimens were analyzed. The results of the cluster analysis and …
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Delimitating Species Boundaries within the Liomys Pictus- Spectabilis Complex (Rodentia: Heteromyidae)
… The purpose of this study was to determine the species boundaries that exist within this complex. I estimated phylogenetic relationships within this complex using sequence data from 1,140 bp of the mitochondrial DNA cytochrome b gene and two nuclear introns from engrailed protein (190 bp) and …
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The origins and maintenance of species boundaries in Jamesbrittenia O. Kuntze (Scrophulariaceae: Manuleae)
The genus Jamesbrittenia contains 83 species distributed throughout southern Africa. Many species produce attractive flowers and consequently their horticultural potential is currently being explored. Speciation patterns and reproductive isolation were investigated in order to identify trends that …
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Reassessment of Species Boundaries and Phylogenetic Relationships in the Desmodium ciliare complex (Fabaceae) Using Morphological and DNA Data
… is a generally weedy genus of approximately 280 species in the angiosperm family Fabaceae (Subfamily Papilionoideae, Tribe Desmodieae) characterized by indehiscent loments constricted into segments. Within the Southeastern U.S., the <em>Desmodium</em> <em>ciliare</em> group is one of two …
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Assessment of species boundaries of the Moringa Ovalifolia (Dinter & A. Berger) in Namibia using nuclear its DNA sequence data
The genus Moringa comprises of thirteen (13) species of trees and shrubs, widely distributed in the tropical and subtropical regions. For its size, this genus is one of the phenotypically varied group of angiosperms whose members are mostly sought after for nutritional, nutraceutical and industrial …
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Phylogenetic relationship of forest spiny pocket mice (Genus Heteromys) inferred from mitochondrial and nuclear markers with implications for species boundaries
… 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 maximum parsimony and …
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Evolution in Neotropical Herpetofauna: Species Boundaries in High Andean Frogs and Evolutionary Genetics in the Lava Lizard Genus Microlophus (Squamata: tropiduridae): A History of Colonization and Dispersal
… on alpha taxonomy, morphological variation, and species boundaries. This work led to new studies initiated and completed at BYU involving further taxonomic revision (Formas et al., 2003; Chapter 1), and then revisiting and re-evaluating species boundaries established earlier (with allozyme …
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A Systematic Revision of Bakeridesia Hochr. (Malvaceae)
… several approaches were used to investigate its species boundaries and phylogenetic relationships. First, phylogenetic analyses of Internal Transcribed Spacer (ITS) sequences provided strong evidence that Bakeridesia is polyphyletic if circumscribed to include the Brazilian subgenus Dipteron. …
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Systematics of the Notonemouridae (Plecoptera) of southern Africa
… African Notonemouridae, were to investigate species boundaries and to infer phylogenetic relationships in the Aphanicerca capensis Tillyard species complex using morphological, behavioural and molecular data (mtDNA), and to model historical biogeographic patterns and drivers of cladogenesis. …
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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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Phylogeography of Marine Meiofaunal Nemerteans of the Ototyphlonemertes Fila Species Complex
… has obstructed studies of speciation and species boundaries among marine meiofauna. Ototyphlonemertes is a genus of meiofaunal nemerteans inhabiting the interstitial spaces of marine sediments. Its members lack pelagic larvae and dispersal potential is believed to be poor. A …
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From Traditional Morphology to Genomes and Machine Learning: Navigating Taxonomic Uncertainties in Southeast Asian Agamids
Classifying species, or the process of identifying, naming, and grouping organisms based on shared characteristics and evolutionary relationships, is critical in many aspects of biology. Without species classification, it would be difficult, if not impossible, for us to understand Earth’s …
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Phylogeny and color pattern evolution in a New World bumble bee (Hymenoptera: Apidae: Bombus: Pyrobombus) species complex
… one of the most common and widespread bumble bee species throughout Mexico and Central America. This robust and charismatic species possesses a highly variable color pattern throughout its wide distribution across montane and lowland regions, which raises the question of whether or not it is in …
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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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Phylogenetic History, Morphological Parallelism, and Speciation in a Complex of Appalachian Salamanders (Genus: Desmognathus)
… and genetic exchange within and among nominal species due to a pattern of high discordance between the two. Phylogeographic hypotheses are tested for populations of the D. quadramaculatus species complex throughout southern Appalachia by combining phylogenetic and population genetic methods …
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Phylogenetic Study of Apocynaceae Juss. And Aspidosperma Mart. And Zucc
The systematic analysis of species boundaries and relationships within the genus Aspidosperma was accomplished with a combination of phenetic and cladistic methods. The phenetic part of the study used principal components analysis (PCA) of morphological variation to establish basic units which were …
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Molecular Systematics & Evolution of the CTENOSAURA HEMILOPHA Complex (SQUAMATA: IGUANIDAE)
… and among other <em>Ctenosaura</em> species are used to identify species boundaries, assess suitable systematic characters, identify evolutionary patterns within <em>C. hemilopha</em> mitochondrial DNA sequences and reconstruct species and area relationships among the various taxa. …
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Female Preference and Prezygotic Isolation In the Fundulus Notatus Species Complex
… isolation arises between closely related species is central to evolutionary research. Hybridization is widespread across taxa and shaped by interactions among environmental factors, evolutionary history, genetic compatibility, and behavior. These forces often operate nonlinearly across …
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