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Evolutionary Trends in the Individuation and Polymorphism of Colonial Marine InvertebratesVenit, Edward Peter. January 2007 (has links)
Thesis (Ph. D.)--Duke University, 2007. / Includes bibliographical references.
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Ecological studies on color polymorphism in the cricket frog, Acris crepitans BairdGray, Robert H. January 1971 (has links)
Thesis (Ph. D.)--Illinois State University, 1971. / Title from title page screen, viewed Sept. 22, 2004. Includes bibliographical references (leaves 44-49). Also available in print.
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The evolution and maintenance of a color pattern polymorphism in neotropical frogs /Crawford, Andrew Jackson. January 2000 (has links)
Thesis (Ph. D.)--University of Chicago, Committee on Evolutionary Biology, December 2000. / Includes bibliographical references. Also available on the Internet.
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Biosystematics of the genus Chionaspis (Homoptera, Coccoidea, Diaspididae) of North America, with emphasis on polymorphismLiu, Tong-Xian January 1987 (has links)
The scurfy scales in the genus Chionaspis comprise a unique taxon among the armored scale insect genera in North America. The taxonomic reviews of the species belonging to the genus by Cooley (1899) and Ferris (1937, 1942) are far outdated.
The present research is a comprehensive review of all the species in this genus in North America, with special emphasis on polymorphism associated with feeding sites which has been discovered in some species. Seventeen species have been redescribed and illustrated in detail, each with a discussion of their morphological affinities and relationships. Their host habits and zoogeography are summarized.
The five species having typical bark and leaf forms, as well as intermediate forms, are discussed in more detail. A separate chapter deals with polymorphism, including a historical literature review of the subject. A hypothesis is given on the modes of transfer from the bark form to the leaf form and vice versa, that results in different morphs in first or second generations. Two keys were prepared: one for the genera related to Chionaspis and another for the determination of the species of this genus in North America.
The three species that have been recently redescribed, C. americana and C. kosztarabi and C. nyssae are also discussed, and the most important morphological characters and the plates prepared by the original authors for each of these three species are given in order to better utilize the key to the species in North America.
As a direct result of this research, two new species have been discovered: Chionaspis gilli Liu and Kosztarab, and C. hamoni Liu and Kosztarab. In addition new morphs were found for C. platani and C. wistariae. This thesis also includes many new distribution and host records for several species.
The phylogenetic relationship of all the species in this study has been discussed, and as a result of the Ward's Minimum Variance Cluster Analysis (1985 version, SAS), a dendrogram has been provided based on 23 numerical characters. / Master of Science
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Natural history and evolution of a color polymorphism in Rana pipiens, the northern leopard frogHoffman, Eric Adam 09 June 2003 (has links)
A primary goal of population genetics is to identify the role of
microevolutionary forces in producing observed patterns of molecular and phenotypic
variation. I conducted four studies in the northern leopard frog, Rana pipiens, to
determine just how mutation, migration, genetic drift, and selection influenced,
genetic structure of mitochondrial DNA (mtDNA), nuclear DNA, and a single locus
polymorphism that determines dorsal coloration. In the first study, I surveyed the
literature concerning color and pattern polymorphisms in anurans. I conclude that
anuran polymorphisms remain a rich but largely unexploited system for studying the
evolution of phenotypic variation in nature.
In the second study, I compared mitochondrial DNA variation from 35
populations distributed across the species' range. A phylogenetic analysis indicated R.
pipiens is split into two deeply divergent mtDNA groups, a western group and an
eastern group. Phylogeographic and demographic analyses indicated that although
restricted gene flow with isolation by distance explained the majority of the processes
influencing current genetic structure, population bottlenecks and expansions also
played an important role.
In the third study, I investigated mtDNA and microsatellite variation in Pacific
Northwest populations of R. pipiens, where a recent range contraction had occurred.
I found that peripheral populations had reduced levels of genetic variation compared to
more interior populations. Moreover, I found that historic samples from peripheral
population already had reduced levels of genetic variation. Therefore, low diversity in
the remnant populations could not be ascribed to the recent range contraction.
In the fourth study, I compared genetic structure from a suite of putatively
neutral molecular markers with that derived from the color polymorphism locus.
Genetic structure at the color locus, assessed both spatially and temporally, was
indistinguishable from structure at neutral loci. This study exemplifies the importance
of investigating for evidence of selective maintenance before studies attempt to
measure the selective mechanisms maintaining a polymorphism.
Overall, my research helps to elucidate how biogeographic and
microevolutionary forces influence a wide-spread North American species, R. pipiens. / Graduation date: 2004
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Polymorphism in twelve species of Neritidae : (Mollusca : Gastropoda : Prosobranchia) from Hong Kong /Huang, Qin. January 1995 (has links)
Thesis (Ph. D.)--University of Hong Kong, 1996. / Includes bibliographical references (leaf 215-251).
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Interplay between environment and genes on morphological variation in perch : implications for resource polymorphisms /Olsson, Jens, January 2006 (has links)
Diss. (sammanfattning) Uppsala : Uppsala universitet, 2006. / Härtill 5 uppsatser.
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Polymorphism in twelve species of Neritidae: (Mollusca : Gastropoda : Prosobranchia) from Hong KongHuang, Qin., 黃勤. January 1995 (has links)
published_or_final_version / Zoology / Doctoral / Doctor of Philosophy
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Adaptation of Drosophila melanogaster to altitudinal and latitudinal climatic gradients : the role of the heat-shock RNA gene hsr-omegaCollinge, Janelle Elyse January 2004 (has links)
Abstract not available
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