Biological Sciences Masters Theses

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Browsing Biological Sciences Masters Theses by browse.metadata.program "Zoology"

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    Development of the Stress Response in Fast (Coturnix Japonica) Versus Slow (Callipepla Gambelii) Growing Species
    (North Dakota State University, 2012) Gastecki, Michelle Lynn
    In this study, we evaluated the development of stress response in (1) two different species of quail, one species that is relatively fast-growing (Japanese quail, Coturnix japonica) and one that is relatively slow-growing (Gambel’s quail, Callipepla gambelii) and (2) two strains of a single species, the Japanese quail (wild-type and domesticated), that differ considerably in final size. Our data indicate that wild-type Japanese quail and Gambel’s quail have experienced trade-offs between growth and the stress response (e.g. Gambel’s quail have slower growth rates, but greater levels of CORT). However, the domesticated strain of Japanese quail used in this study seem to violate some predictions based on the life history theory (e.g. the domestic strain has faster growth rates and greater levels of CORT). The data in this study contribute to the understanding of differences in the stress response between species that exhibit different life history strategies.
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    Environmental Components of Phenotypic Variation Dietary and Trans-Generational Effects on Behavior
    (North Dakota State University, 2017) Garrison, Courtney
    Phenotypic variation, or the total variation in a trait, and its components are of great importance in the fields of evolutionary and behavioral ecology. Phenotypic variation can be broken down into both environmental and genetic influences on that particular trait. However, due to an increasing trend of quantitative genetics in behavioral studies, researchers have begun to consider lesser studied components of phenotypic variation in addition to the commonly studied direct environmental and genetic influences. Some of these lesser studied components include maternal and paternal effects, or the effect that parental phenotype has on their offspring’s phenotype. In Chapter 1, I examine the impacts of direct environmental manipulation on cricket song production. For Chapter 2 however, instead of examining the direct environmental influence at the individual level, I examine, through meta-analysis, how the indirect environmental influences that occur at both the maternal and paternal level impact offspring phenotype across taxa.
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    Evolution of the Growth Hormone Receptor: Insights Into the Molecular Basis of the Physiologically Pleiotropic Nature of the Growth Hormone Receptor
    (North Dakota State University, 2014) Ellens, Elizabeth Rose
    One of the oldest, extant, lineages of vertebrates, the sea lamprey, was used to clarify the evolutionary origin and divergence of the growth hormone receptor (GHR) family. A single, full-length, cDNA, and a second, partial, cDNA were identified and shown to encode proteins that share amino acid identity with GHRs and prolactin receptors (PRLR s) previously identified. The complexity of the dynamic signaling system, with special emphasis on this system in fish and in the context of the evolution of this system, is discussed in the first chapter. The second chapter integrates the new insights gained by these studies. Included is a newly proposed phylogenetic analysis and revised nomenclature-system for vertebrate GHRs that better represents the evolutionary history of the receptor family. The molecular evolution of the receptors is, furthermore, highlighted as the backdrop for the continued discussion regarding how the GH-family of hormones exhibit such coordinated and pleiotropic actions.
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    From Alcelaphus to Zapus: Conservation of Modern Mammalian Populations
    (North Dakota State University, 2015) Preston, Kathryn Anne
    Conservation priorities are increasingly important in the face of modern human activities. Anthropogenic activities such as deforestation, pollution, and climate change have negative impacts on all vertebrates. In chapter 1, I examine whether there are relationships among density dependence, population size variability, and extinction risk in mammals to see whether these parameters are indicative of population health. Also included were analyses of how body mass and age to maturity affect those three measures. On a smaller, more local scale, I asked questions regarding biodiversity of small mammals in a highly fragmented environment, the tallgrass prairie. In chapter 2, I examined how cattle grazing impacts small mammal biodiversity in the Sheyenne National Grassland on a short term, season-long scale. By understanding the interaction of large herbivores, vegetation height, and small mammals, appropriate measures can be taken to conserve this rare habitat properly, without sacrificing biodiversity.
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    Growth Hormone Mediated Regulation of Osmoregulation in Euryhaline Teleosts
    (North Dakota State University, 2014) Martin, Lincoln
    Within the multitude of fish species that exist on our planet, there are a certain number that possess the unique ability to live in both freshwater (FW) and seawater (SW) environments. This ability, known as euryhalinity, is limited to a relatively small number of species, thus making it a prime target for scientific research into osmoregulation, due to the uniqueness of this ability. It has been shown previously that growth hormone (GH) plays an important role in regulating this ability, and in this work, Atlantic salmon (Salmo salar) and Rainbow trout (Oncorhynchus mykiss) were used as models to examine the expression of specific osmoregulatory genes in response to SW transfer and GH exposure, and to examine the signaling mechanisms used by GH to facilitate any changes. We found that GH utilizes specific cell signaling pathways to facilitate the transition between FW and SW in both Rainbow trout and Atlantic salmon.