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.
Results
Showing 1 to 20 of 23 for “"Mass Extinctions"”.
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High-precision U/Pb geochronology of large igneous provinces and mass extinctions : testing coincidence and causation
The history of life on Earth is punctuated by mass extinction, the cause of which has often been attributed to rapid changes in global climate and/or ocean chemistry that are inferred to accompany the eruption of large igneous provinces (LIPs). Implicating LIP eruptions as the trigger of the …
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My responsibility in the face of mass extinction
… or group” (Hine and Martin 2015g, para. 1). Mass extinctions are extinctions of the greatest magnitude, occurring “when many diverse groups of organisms become extinct over short periods of time” (Condie 2011, 250). These “are not step-events but rather a step into a prolonged alternative …
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Statistical analyses of extinction in the marine fossil record
… performed to determine whether the magnitudes of mass extinctions were statistically distinguishable from the magnitudes of background extinctions. The expected proportions of familial extinction for each order in a stage (based on an estimate of the ordinal probability of familial extinction for …
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Unraveling Paleoenvironmental Stress in the Late Devonian and Mississippian: Insights into Redox Dynamics and Photosynthetic Adaptations Elucidated Through Geochemical Proxies
… our planet. They contain one of the five major mass extinctions of the Phanerozoic which saw profound environmental and ecological disturbances and changed the trajectory of both marine and terrestrial ecosystems. The proliferation of vascular plants on land, major marine transgressions over the …
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Four problems in nonlinear Earth system dynamics
… events, “Snowball Earth” glaciations, and mass extinctions. Although the details are different, underpinning them all is the nonlinearity of the Earth system: small changes sometimes trigger much larger responses. This thesis addresses four related problems in this subject area. First, I …
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A Study of Evolutionary Contingency: Characterisation, Mechanisms, and Evidence
… genetic drift, species sorting, and mass extinctions. I conclude that random mutations fail to be a strongsource of contingency as they are often biased towards particular mutational outcomes on account of certain physical dispositions. On the other hand, mass extinctions and some …
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Ecological Responses to Climate Change: Using the Common Ragworm (Hediste diversicolor) as an Indicator for Benthic Ecosystems
… of kill mechanisms that led to the extreme mass extinctions observed in the geological past.
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Testing the ancient marine redox record from oxygenic photosynthesis to photic zone euxina
… zone (i.e. photic zone euxinia; PZE) during mass extinctions and oceanic anoxic events. Here, the molecular fossil evidence for oxygenic photosynthesis and eukaryotes is reevaluated, where the results imply that currently existing lipid biomarkers are contaminants. Next, the stratigraphic …
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Testing the ancient marine redox record from oxygenic photosynthesis to photic zone euxina
… zone (i.e. photic zone euxinia; PZE) during mass extinctions and oceanic anoxic events. Here, the molecular fossil evidence for oxygenic photosynthesis and eukaryotes is reevaluated, where the results imply that currently existing lipid biomarkers are contaminants. Next, the stratigraphic …
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Carbonatites as a record of the carbon isotope composition of large igneous province outgassing
… with negative carbon isotope excursions and mass extinctions.</p>
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Inculturation: with special reference to the Catholic Church in Lesotho and to liturgy
… the long-term survival of many species. Avian extinctions since 1600 have been well documented relative to other taxa, as have current levels of avian threat. This study analyses avian extinctions post-1600 and current threats in an attempt to develop some predictive capacity about which avian …
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The causes of avian extinction and rarity
… the long-term survival of many species. Avian extinctions since 1600 have been well documented relative to other taxa, as have current levels of avian threat. This study analyses avian extinctions post-1600 and current threats in an attempt to develop some predictive capacity about which avian …
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The causes of avian extinction and rarity
… the long-term survival of many species. Avian extinctions since 1600 have been well documented relative to other taxa, as have current levels of avian threat. This study analyses avian extinctions post-1600 and current threats in an attempt to develop some predictive capacity about which avian …
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Interpreting television: Teleconsciousness and the development of a creative curriculum
… the long-term survival of many species. Avian extinctions since 1600 have been well documented relative to other taxa, as have current levels of avian threat. This study analyses avian extinctions post-1600 and current threats in an attempt to develop some predictive capacity about which avian …
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Accessing silence : research methods into sexual harassment : a case study of the Committee of Enquiry into Sexual Harassment at the University of Cape Town
… the long-term survival of many species. Avian extinctions since 1600 have been well documented relative to other taxa, as have current levels of avian threat. This study analyses avian extinctions post-1600 and current threats in an attempt to develop some predictive capacity about which avian …
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The Effects of Contact Metamorphism by Diabase Intrusion on the Carbon and Sulfur Bearing Phases in the Siltstones of the Culpeper Basin
… the Phanerozoic have been temporally linked to mass extinction events. The intrusion of magma into country rock has been hypothesized to facilitate the release of carbon and sulfur bearing volatiles and has been proposed as one of mechanisms that drove these mass extinctions. In this study I …
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Quantifying the Biogeochemical Impact of Land Plant Expansion in the Mid Devonian and Implications in Marine Anoxic Events
… about the causes of marine eutrophication and mass extinctions during the Devonian. To gain insight into the transport of P between terrestrial and marine domains, presented here are geochemical records from a survey of Middle and Late Devonian lacustrine and near lacustrine sequences that span …
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Marine Deoxygenation Predates the End-Triassic Mass Extinction Within the Equatorial Panthalassa and its Influence on Marine Ecosystems Before the Biotic Crisis
The end-Triassic Mass Extinction (ETME) was one of the "Big 5" mass extinctions of the Phanerozoic and is thought to have been caused by a series of environmental changes triggered by the emplacement of the Central Atlantic Magmatic Province (CAMP). While the overall driver of the ETME is …
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BUILDING FRAMEWORKS FOR UNDERSTANDING INVASIONS AND EXTINCTIONS FOR BIODIVERSITY SCIENCE
… levels and has drawn comparisons to previous mass extinctions. The ongoing Holocene–Anthropocene extinctions differ from prior biodiversity loss, because humans have been directly implicated as major drivers of current loss—overexploitation, habitat modification and destruction, climate …
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The evolution of convergence, growth, and diet under an adaptive landscape framework
… However, the Triassic Period is bookended by mass extinctions, and is thus a useful case study to explore the utility of adaptive landscape theory for organisms in a time of rapid environmental change. My dissertation explores convergence and growth through an adaptive landscape framework, to …
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