Thesis (M.S.)--Miami University, Dept. of Zoology, 2007. / Title from first page of PDF document. Includes bibliographical references (p. 17-19).

Thesis (Ph. D.)--University of Alberta, 2010. / Title from pdf file main screen (viewed on June 11, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Environmental Biology and Ecology, Department of Biological Sciences, University of Alberta. Includes bibliographical references.

No description available.

Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on September 25, 2007) Vita. Includes bibliographical references.

Environmental stressors are ubiquitous. Animals will face a variety of natural and anthropogenic stressors throughout their life cycle. The physiological mechanisms that mediate stressful stimuli can have pleiotropic effects on life history traits, such as reproduction and development. Furthermore, these phenotypic changes can affect larger-scale ecosystem dynamics, like nutrient cycling and disease epizootics. Animals are not equally susceptible to stressors across all stages of their life cycles. Critical windows of development, common in young and developing animals, are time periods when stressors have an outsized effect and can permanently alter phenotype. Larval amphibians use a critical window in late larval development wherein activation of the hypothalamic-pituitary-adrenal/interrenal (HPA/I) axis speeds their development, allowing them to metamorphose and escape suboptimal aquatic habitat. Accelerated development comes at a cost, the glucocorticoid (GC) hormones secreted by the HPA/I axis affect other systems such as growth, immune function, metabolism, and nutrient use. In chapter two, I investigated the effects of GC hormones on metabolism, energetics, and nutrient oxidation in larval wood frogs. The results show that GC hormones increase metabolism, reduce lipid stores, and increase protein oxidation during metamorphic climax. Chapter three focuses on the effects of GC hormones on immune function and r susceptibility. I found that chronic exposure to GC hormones increased ranavirus replication in infected wood frog larvae, but did not affect survival time. This could contribute to ranavirus epizootics. Acute GC hormone exposure increased survival, possibly by activing the inflammatory response. Finally, chapter four investigates the effects of GC hormones on nutrient stoichiometry. I found that larvae treated with GC hormones had lower nitrogen to phosphorus ratios, possibly because disrupted skeletal ossification. They also had reduced phosphorus excretion, which could affect ecosystem-level processes like nutrient cycling and decomposition.

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In this study, I used restriction fragment length polymorphism (RFLP) analysis (DNA fingerprinting) to study the genetic population structure of wood frogs, Rana sylvatica, collected as egg masses from vernal pools within the Massachusetts Audubon Society Lincoln Woods Wildlife Sanctuary in Leominster, MA. The average genetic relatedness of sibling individuals, non-sibling individuals from within the same pool, and individuals from pools of close (5 m), far (200 m) and distant (40 km) spatial separations was calculated. The goal was to use genetic relatedness to estimate the breeding patterns of R. sylvatica and use that information to make general management recommendations that could be applied to other vernal pools breeders. I detected relative differences in genetic similarity between individuals from pools only 5 meters apart, however over a larger distance of 200 meters no significant genetic differences were present. This suggests that although wood frogs are known to be highly philopatric, they may use information other than simply proximity to their natal pool when choosing breeding sites. Factors such as species composition, water chemistry and heterogeneity of the landscape between pools may influence breeding site choice. Also, contrary to the findings of recent studies, the distance between vernal pools may not be the best indicator of the genetic similarity of the individuals they host. Pools in close proximity to one another may host genetically distinct populations, and therefore management decisions should be made on a pool-by-pool basis. Consequently, when managing populations of R. sylvatica, and possibly other vernal pool breeders, taking into account parameters other than simply the spatial separation of pools within an array may avoid decisions that could result in the loss of genetic diversity.

Theses (M.S.)--Marshall University, 2006. / Title from document title page. Includes abstract. Document formatted into pages: contains vi, 65 p. including illustrations and maps. Bibliography: p. 61-65.

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No description available.