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 20 of 464 for “"Biology, Zoology"”.
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A study of the river redhorse, Moxostoma carinatum (Pisces; Catostomidae), in the tributaries of the Ottawa River, near Canada's National Capital and in a tributary of Lake Ontario, the Grand River, near Cayuga, Ontario.
This study provides baseline data on the River Redhorse (Moxostoma carinatum; Moxostomatini: Catostomidae) in Canada. Sampling focussed on the Mississippi and Gatineau Rivers, in the National Capital Region, in 1998 and 1999. Spawning occurred in rocky, shallow (<2m) fast-water sections in May …
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Control of heart development in the Mexican axolotl (Ambystoma mexicanum).
The locations and migration of the embryonic primordia which form the heart are well known. However, the processes whereby the heart-forming mesoderm is induced, and the later mechanisms controlling the differentiation and morphogenesis of the heart are only poorly understood for any system. An …
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Habitat Selection by Yellow -Headed Blackbirds
Migratory birds have the ability to select a breeding site from a large number of sites across a large geographic area. Therefore, one might expect that migratory birds would select the site where they would realize the greatest fitness. However, little is known about how and why migratory birds …
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Environmental, Landscape, and Host-Related Factors Associated With Parasitism and Its Effects on Larvae and Metamorphic Frogs of Rana Pipiens
The emergence of several diseases affecting amphibian populations worldwide has prompted investigations into factors that determine the distribution and abundance of parasites in frogs. Environmental and land use determinants of the structure of parasite communities of metamorphic frogs of Rana …
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The Influence of Population and Community Variables on Bluegill, Lepomis Macrochirus, Life Histories: Implications for Growth Rates, Timing-of-Maturation, and Population Size Structure
Vertebrate life histories are complex and can be shaped by myriad population- and community-level variables. I conducted a series of experiments to examine aspects of bluegill, Lepomis macrochirus, life histories in an attempt to quantify variables influencing growth and maturation rates of …
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Living at the Edge: Effects of Forest Edges on Populations of White -Footed Mice (Peromyscus Leucopus)
To reconcile the apparent contradiction between these results and studies that reported a negative relationship between white-footed mouse density and woodlot area, I reanalyzed the data from the most extensive of these studies. This revealed that the addition of a 7.5 m boundary strip to the …
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Factors Influencing the Functional Roles of Crayfish in Stream Ecosystems
Results supported an important role for juvenile crayfish in both systems. At Jordan Creek, juveniles were >10 times more abundant than adults during summer and likely accounted for the majority of crayfish effects in the stream. At Shivering Sands Creek, small crayfish greatly reduced the …
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A Phylogenetic Study of Cymopterus and Related Genera (Apiaceae)
Considerable confusion exists with regard to the delimitation of Cymopterus and its relationship to other perennial genera of Apiaceae subfamily Apioideae endemic to western North America (north of Mexico). Cladistic analyses of nuclear (rDNA internal transcribed spacer) and chloroplast ( rps16 …
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The Effects of Two Polychlorinated Biphenyl Mixtures on Honey Bee (Apis Mellifera) Foraging Behavior and Hypopharyngeal Gland Development
The honey bee is a novel model in which to study physiological and behavioral changes that may have a hormonal influence. This dissertation focused on the effects of two PCB mixtures, Aroclor 1242 and 1254, on the European honey bee, Apis mellifera, as there is evidence that these compounds disrupt …
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Population Genetic Structure of the Introduced North American Population of the Hornet, Vespa Crabro Germana Christ
Mitochondrial sequence data revealed that the probable source for the North American population was Germany. The data also suggested that the founding group was small; there was but a single mitochondrial haplotype represented for North America at the three loci investigated (COI, COII and …
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A Systematic Revision of the Genus Hypomicrogaster Ashmead (Hymenoptera: Braconidae): A Phylogenetic Approach
… was presented, including clarification of its biology. Description is also made of the first two species of the genus Austrocotesia Austin & Dangerfield for the New World (Austrocotesia croizatii and A. renei), with a comprehensive key for the world known species.
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Systematics of the Leafhopper Subfamily Deltocephalinae (Hemiptera: Cicadellidae) and the Tribe Chiasmini: Phylogeny, Classification, and Biogeography
Based on the number of described species, the leafhopper subfamily Deltocephalinae is the largest subfamily of Cicadellidae, containing ∼850 genera and over 6200 described species. Chapter 1 provides a detailed introduction to this subfamily and to the tribe Chiasmini. Chapter 2 presents a …
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Morphometric Theory and Application to Evolution and Biogeography in Argopecten (Bivalvai: Pectinidae) From the Southeastern United States
Evolution in the Argopecten irradians lineage shows early onset of circular disk morphologies similar to modern forms, with subsequent evolution through punctuated selection against more archaic (asymmetrical) morphologies, likely associated with Pleistocene glaciations. That speciation mirrors …
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Molecular Profiling: Gene Expression Reveals Discrete Phases of Lens Induction and Development in Xenopus Laevis
"From these genes, two were examined to further characterize their roles in development and transdifferentiation. The matrix metalloproteinase Xmmp-9 was found to function during migratory and morphogenetic processes during development, and it was found to be upregulated during wound healing. Psf2 …
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Tests of Functional Equivalence Among Aquatic Predatory Vertebrates
Many ecological studies and theories assume that species occupying similar trophic positions perform similar functions on population, community, and ecosystem dynamics (i.e., they are functionally equivalent). This is particularly true for models predicting (i) the effects of one trophic level upon …
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Life-History Evolution and Population Dynamics of a Neotropical Forest Bird (Hylophylax Naevioides)
Finally, I investigated nest-reuse decisions made by Spotted Antbirds and found that over a quarter of all nest attempts were located at a previously used nest site. Pairs were more likely to reuse previously successful nests, especially for a consecutive nest attempt, than previously depredated …
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Comparative Phylogeography of Eastern Chipmunks and White -Footed Mice: Population Histories Since the Last Glacial Maximum
Finally, analyses of variation at 6 microsatellite loci among 210 P. leucopus from three sites each around three of the largest cities in Illinois recovered reduced levels of gene flow among sites separated by urban development compared to sites separated by deciduous forest habitat. Mitochondrial …
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Systematic Studies of the Orangethroat Darter, Etheostoma Spectabile, Complex (Percidae: Subgenus Oligocephalus)
A morphological and allozymic examination of variation within populations previously recognized as the orangethroat darter, Etheostoma spectabile, with an emphasis on populations occurring south of the Ohio River in Kentucky and Tennessee and a reexamination of populations occurring in the Ozarks, …
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Phylogenetic Relationships of the Sucker-Mouth Armored Catfishes (Loricariidae) With Particular Emphasis on the Ancistrinae, Hypostominae, and Neoplecostominae
The genera and tribes of Hemipsilichthiinae, Hypostominae, Neoplecostominae, and Upsilodinae are redescribed and diagnosed. A key is provided for all of the genera of Hemipsilichthiinae, Hypostominae, Lithogeneinae, Neoplecostominae, and Upsilodinae.
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