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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Comparative phylogeography of five swallowtail butterfly species (Lepidoptera: Papilionidae) in South Africa : ecological and taxonomic implications.

Neef, Götz-Georg January 2014 (has links)
With current biota under constant threat of extinction, it is important to ascertain where and how biological diversity is generated and partitioned. Phylogeographic studies can assist in the identification of places and processes that indicate the origin and maintenance of biodiversity. Forest fragmentation has a big effect on local extinction and loss of genetic diversity of forest-restricted taxa, along with divergence and speciation of forest biota. This study aims to understand the effects of these processes on a number of forest-dwelling butterflies using a comparative phylogeographic approach. Mitochondrial DNA of five different Papilio species with different degrees of forest specificity was analysed using phylogenetic methods. In addition, the subspecific taxonomy of P. ophidicephalus was investigated using morphometrics of discal spots on the wings and nuclear DNA analysis along with mitochondrial DNA analysis. The results show that the forest-restricted species (P. ophidicephalus and P. echerioides) have more genetic structure and less genetic diversity than the more generalist species (P. dardanus, P. demodocus and P. nireus). This could be due to inbreeding depression and bottlenecks caused by forest fragmentation. As forest patches become smaller, the population size is affected and that causes a loss in genetic diversity, and increasing habitat fragmentation disrupts gene flow. The intraspecific taxonomy of P. ophidicephalus is far from revealed. However, this study shows there is evidence for the different subspecies when comparing morphological results and genetic results. From the evidence provided here it is suggested that P. ophidicephalus should be divided into two separate species rather than five subspecies.
2

Trophic cascades: Linking ungulates to shrub-dependent birds and butterflies

Teichman, Kristine J Unknown Date
No description available.
3

Geometria extrínseca de superfícies singulares de R3 / Extrinsic Geometry of Singular Surfaces in R3

Cruz, Douglas Hilário da 16 April 2013 (has links)
Submitted by Erika Demachki (erikademachki@gmail.com) on 2014-10-22T19:41:10Z No. of bitstreams: 4 Dissertação - Douglas Hilário da Cruz - 2013 - PARTE 01.pdf: 20946472 bytes, checksum: 1f5cc7eeda54593cff53f3c563b23faa (MD5) Dissertação - Douglas Hilário da Cruz - 2013 - PARTE 02.pdf: 20125557 bytes, checksum: 9c30c03de1a6b7fb3f356cc931d61534 (MD5) Dissertação - Douglas Hilário da Cruz - 2013 - PARTE 03.pdf: 266901 bytes, checksum: 97410256533198e3a3b180056a740526 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Jaqueline Silva (jtas29@gmail.com) on 2014-10-22T20:18:04Z (GMT) No. of bitstreams: 4 Dissertação - Douglas Hilário da Cruz - 2013 - PARTE 01.pdf: 20946472 bytes, checksum: 1f5cc7eeda54593cff53f3c563b23faa (MD5) Dissertação - Douglas Hilário da Cruz - 2013 - PARTE 02.pdf: 20125557 bytes, checksum: 9c30c03de1a6b7fb3f356cc931d61534 (MD5) Dissertação - Douglas Hilário da Cruz - 2013 - PARTE 03.pdf: 266901 bytes, checksum: 97410256533198e3a3b180056a740526 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-10-22T20:18:04Z (GMT). No. of bitstreams: 4 Dissertação - Douglas Hilário da Cruz - 2013 - PARTE 01.pdf: 20946472 bytes, checksum: 1f5cc7eeda54593cff53f3c563b23faa (MD5) Dissertação - Douglas Hilário da Cruz - 2013 - PARTE 02.pdf: 20125557 bytes, checksum: 9c30c03de1a6b7fb3f356cc931d61534 (MD5) Dissertação - Douglas Hilário da Cruz - 2013 - PARTE 03.pdf: 266901 bytes, checksum: 97410256533198e3a3b180056a740526 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2013-04-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In this work we study asymptotic lines in the neighborhood of a singular point, lines of curvature in the neighborhood of singular curves of ellipsoid wave fronts and the lines of curvature in the neighborhood of the Darbouxian umbilic points. / Neste trabalho estudamos as linhas assintóticas na vizinhança de um ponto singular, as linhas de curvatura na vizinhança das curvas de pontos singulares das frentes de ondas do elipsóide e as linhas de curvatura na vizinhança dos pontos umbílicos Darbouxianos das frentes de ondas de uma superfície regular.

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