Browsing Department of Biology Graduate Theses by Title
Now showing items 82-101 of 344
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Daphnia vertical position and implications for the impact of the invasive zooplankton predator, Bythotrephes longimanus, on plankton communities in south-central Ontario
Species diversity and identity play an important role in determining community structure and regulating ecosystem processes. However, species interactions are often characterized by the mean effect or response, often ... -
Delayed maturation of secondary sexual signals in first-year male American redstarts
(2009-09-26)Male birds of many species use conspicuous song and plumage displays in both courtship and territorial interactions. In some species, one or both of these signalling traits may not reach full adult maturity until a male’s ... -
Determining Expression, Regulation, and Stoichiometries of Cytochrome C Oxidase Subunit IV Paralogs in Fish
(2015-04-07)Cytochrome c oxidase (COX) is complex IV of the electron transport chain and catalyzes the reduction of oxygen to water. It also simultaneously translocates protons from the mitochondrial matrix to the inter-membrane space, ... -
Determining the distribution and fate of mercury in sediments of the Cataraqui River at Kingston, Ontario
(2007-11-02)The Cataraqui River, which drains 930 square km of watershed before emptying into the inner harbour of Kingston, Ontario (pop: 113,000), has a long history of anthropogenic use. More than 40 industries have existed within ... -
Developmental Regulation of Cell Fate And Disease Resistance in Plants
(2010-10-20)Plant-wide communication between tissues and cells is organized, in part, by a suite of compounds called hormones. I have chosen to focus on the effects of one plant hormone, ethylene; how its synthesis is controlled and ... -
Developmental, but not activational, roles for estradiol and its receptor in paternal and sexual behaviour of Phodopus campbelli males
(2008-09-17)The neuroendocrine basis of paternal behaviour is hypothesised to be homologous to that of maternal behaviour, with the expression of paternal behaviour resulting from the activation of estrogen-sensitive pathways in the ... -
Diatom Assemblages in Relation to Water-Depth Gradients in Eight Boreal Shield Lakes From Northwestern Ontario, Canada
(2010-07-23)The uncertainty surrounding the impact of future changes in climate and water resources has created renewed interest on how lakes have responded to drought in the past. There is a need to determine potential future available ... -
Diatom Community Responses to Water Quality Improvements in Lakes Recovering From Acidification and Metal-Contamination Near Wawa, Ontario, Canada: a Paleolimnological Perspective
(2009-04-30)In response to sulphur dioxide emission reductions in North America and Europe, there has been a recent shift in research focus towards understanding ecosystem recovery. Evidence for reversibility in the effects of ... -
A diatom-based paleolimnological investigation of historical water-quality and ecological changes in the Lake of the Woods, Ontario
(2010-05-28)A two-part paleolimnological study was conducted to examine changes in historical and modern water-quality in Lake of the Woods (LoW) in response to multiple stressors, such as climate change and shoreline residential ... -
A diatom-based paleolimnological study of water-quality changes related to multiple anthropogenic stressors in Lake Simcoe
(2010-08-04)Freshwater systems in Canada are affected by a multitude of environmental stressors, including cultural eutrophication, introduction of non‐native species, and climate change. Multiple stressors can interact in unpredictable ... -
Diatom-Inferred Changes in Effective Moisture From Gall Lake, Northwestern, Ontario, Over the Past Two Millennia
(2011-06-07)The boreal forest of Canada extends across 58% of Canada’s land area providing a large range of ecosystem services including flood control, water filtration, and carbon storage. Despite conservation efforts to protect this ... -
Diatoms as Bioindicators of Environmental Change in Cape Herschel and Pim Island (Nunavut, Canada) Ponds
(2016-02-29)The High Arctic is especially sensitive to climatic change, but typically direct long-term monitoring data are lacking. Instead, paleolimnological approaches are now widely used to reconstruct past environmental changes. ... -
Diatoms as Indicators of Environmental and Climatic Change in Peatlands and Lakes Located Across the Boreal Shield and Hudson Bay Lowlands of Canada
(2014-12-19)Long-term monitoring data and paleoecological records are lacking in the Far North of Ontario (~50- 57oN, 79-94oW), a region of ecological and economic significance to Canada. As a landscape covered by extensive peatland ... -
Divergent fish mercury trends in two South-Central Ontario lakes and the relationship to changes in atmospheric sulfate deposition
(2013-01-11)Environmental conditions can lead to mercury accumulations in fish that are highly variability among spatially close lakes in Ontario, Canada. Mercury methylation caused by sulfate reduction can influence total mercury ... -
Diversity and function of the soil microbiome in a North American forest in response to Alliaria petiolata (garlic mustard) invasion.
The disruption of soil microbial communities is thought to be a major contributor to the expansion of invasive plants. Previous research has focused on identifying how invasive plants change soil microbial diversity and ... -
Do Species with Strong Apical Dominance Incur a Cost in Terms of Suppressed Potential Fecundity or Biomass?
Plants typically allocate axillary meristems to one of three principal fates: growth (G), reproduction (R), or inactivity (I). The latter is commonly enforced by ‘apical dominance’, promoting a growth form that favours ... -
Does the goldfish COX4-1 gene promoter possess cold-responsive elements?
(2015-04-30)Mitochondrial biogenesis permits tissues to increase mitochondrial content in response to environmental and physiological stressors. In many species of fish mitochondrial biogenesis is triggered by cold exposure. The greater ... -
A Duality in Mammalian Glucocorticoid Signaling
(2010-01-25)I tested a prevalent assumption in glucocorticoid research that states that each species has a dominant glucocorticoid, and cortisol and corticosterone are interchangeable steroids. A comprehensive analysis of historical ... -
Ecological Differentiation in a Hybridizing Cryptic Species Complex
(2012-01-04)The hybridizing Daphnia mendotae and D. dentifera (Crustacea: Cladocera) are sympatric throughout much of North America, and are considered a cryptic species complex due to their lack of phylogenetically informative ... -
Ecological effects of Hemimysis anomala on the nearshore fish community of Lake Ontario
(2012-04-05)Species invasions are regarded as one of the most serious threats to biodiversity and native ecosystems and our ability to predict and quantify the impacts of invasive species has been an arduous task. Since the 1840s, the ...