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 12 of 12 for “"species diversification"”.
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Sistemática, filogenia e biogeografia do grupo Characidium lauroi Travassos, 1949 (Characiformes, Crenuchidae)
… "Characidium lauroi" group is composed by five species, that inhabit small mountains streams, such as the tributaries of the Iguaçu, Paranapanema, Tietê and Paraíba do Sul rivers, and coastal streams between Ilha Grande bay and Ribeira de Iguape. Four of these species were described by Haroldo …
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Chromosomal inversions and common quail diversification in Macaronesian archipelagos and the mainland
… fragmentation (islands) contribute to the diversification of a bird lineage. Specifically, we focus on the role of chromosomal inversions in maintaining polymorphisms within the highly mobile common quail (Coturnix coturnix), and the impact these structural changes have on the population …
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Evolutionary perspectives on plant responses and sensitivity to environmental change
… evolutionary outcomes and sensitivity of species to future environmental change. These processes are especially relevant to highly diverse, evolutionarily rich, and ecologically vulnerable alpine ecosystems. My PhD aims to narrow the uncertainty about how plant lineages with a range of …
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TAXONOMY AND PHYLOGENOMICS OF CHRYSOBALANACEAE
… is a pantropical woody plant family of 546 species and 27 accepted genera. Its centre of diversity is the Amazon where it is among the most numerically important in both number of species and individual trees in forest tree inventories. The family has been extensively studied at the …
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Geographic patterns of speciation in West and Central Africa: The role of rivers, mountains, and refugia
… However, the roles of these factors in driving diversification in Central Africa are generally poorly understood. A major sampling gap exists for many taxa in the Congo Basin, and pollen core and fossil data tend to be poorly preserved in the tropics. In addition, many climatic and geologic …
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Evolutionary history of the canary grasses (Phalaris, Poaceae)
Canary grasses (Phalaris, Poaceae) include 21 species widely distributed throughout temperate and subtropical regions of the world with centers of diversity in the Mediterranean Basin and western North America. The genus contains annual/perennial, endemic/cosmopolitan, wild, and invasive species …
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Evolution in biological radiations; insights from the Triassic archosaur radiation
Adaptive radiations, or evolutionary diversifications, are the evolutionary divergence of a single lineage into many different adaptive forms. They play a critical role in the history of life as groups of organisms speciate and fill new ecological roles over geologically rapid time intervals. There …
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Transcriptional divergence during cichlid embryogenesis
… average nucleotide diversity within and between species. This low variation at the genomic level cannot fully explain the great diversity at the phenotypic level. Transcriptomes can thus serve as an intermediate phenotype to understand how variation is manifested at the gene expression levels. …
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From Micro to Macro: Investigating mechanisms involved in the convergent evolution of feather lice ecomorphs
… hundreds of millions of years, the diversity of species that have evolved prompts questions about how and why species diversify and adapt to novel environments. In some instances, distantly related species will evolve similar traits, in a process called convergent evolution. These occurrences …
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Comparative Population Genomics and Speciation of Snakes Across the North American Deserts
… I first quantify the degree to which these species groups have a shared history of population divergence across a well-documented phylogeographic barrier, the Cochise Filter Barrier (CFB), and estimate the timing of divergence for each taxon pair using a single locus. This study reveals 1) …
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Epigenetic variability and inheritance in East African cichlid fishes
The hundreds of cichlid species forming part of the radiation of East African Lakes show a remarkable diversity of phenotypic and ecological adaptation. Despite this, recent studies highlighted that genetic diversity within the radiation is among the lowest ever observed in vertebrates. Such a high …
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Systematics of the Relhaniinae (Asteraceae-Gnaphalieae) in southern Africa : geography and evolution in an endemic Cape plant lineage
… relevant for the Cape where high rates of species diversification and the ongoing maintenance of species proliferation is hypothesised. Subtribe Relhaniinae of the daisy tribe Gnaphalieae is one such little-studied lineage. The taxonomic circumscription of this subtribe, the biogeography of …