Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--Syracuse University, 2009. / "Publication number: AAT 3385841."

<p> Recent studies have used ecomorphological methods to look at morphological variation in artiodactyl postcranial elements as indicators of paleoenvironment conditions. From these studies, a continuum of variations in the lower limb bones of members of Bovidae and Cervidae in association with habitat conditions have been developed. The focus of this study is to look at variation in a single species, white-tailed deer (<i>Odocoileus virginianus</i>), that occupies a wide range of habitats and determine if regional adaptations exist in populations of different habitat conditions. </p><p> This studies uses linear measurements to assess size and shape variations in the metacarpal, metatarsal, astragalus, and calcaneus between white-tailed deer populations associated with open- and closed-habitat conditions thought-out the Holocene and in modern populations. The Holocene was subdividing into three time units (10,000-5,000, 5,000-3,000, and 3,000-1,000 yr BP) based on environmental shifts and availability of samples. Variations in size and shape were assessed for 1) in open- and closed-habitat conditions in both Holocene and modern deer overall, 2) in habitat conditions in open-classified Holocene deer through time, 3) in modern deer populations along a latitudinal transect,4) between Holocene and modern deer overall, and5) in Holocene and modern for open-classified and closed-classified deer. </p><p> Results indicated that size differences existed between open- and closed-classified deer in both Holocene and modern populations and that deer associated with open-habitat were larger. Shape differences between open- and closed-classified deer in the Holocene appear to be adapted to the environment, however, modern deer offered only limited insight and lacked consistence in variations. Results for variation thought time in Holocene deer indicated that size increased from Early to late Holocene in both the astragalus and calcaneus. Results for shape offered limited and mixed results. Results for variation in population along a latitudinal transect indicated that deer size increase from lower to higher latitudes. Results for shape differences between populations offered limited insight into variation. However, results for the calcaneal tuber functional region did indicated that deer become more open-adapted in relation to the southern population from lower to higher latitudes,. For the comparison of Holocene and modern deer size overall, only the astragalus indicated a clear variation between the two. The astragalus indicated that Holocene deer were larger than modern deer. Results for variation in shape between the two indicated little difference between the two except for the calcaneus, which indicated that modern deer were more open-adapted. Results for size differences in Holocene and modern for open-classified and closed-classified deer offered limited and mixed results. Results for shape differences were also limited; however, the calcaneus strongly indicated that modern closed-classified deer are more open-adapted than Holocene closed-classified deer.</p>

<p> Investigation of decapod fossils from the Pawpaw Shale, Albian, Texas, has yielded 17 new species, and seven new genera. In total, 14 brachyuran; 3 astacidean; 4 anomuran; 8 axiidean; 5 palinuridean, and one stomatopod species were described and classified according to the latest classification scheme. Shale samples from a single locality in Fort Worth were analyzed for their grain size, mineral and trace element content. The Pawpaw Shale consists of sediments derived from the Llanos uplift to the southwest of Fort Worth, and represents a fining upward sequence deposited in a restricted lagoonal environment. The decapod fauna of the Pawpaw Shale is one of the richest decapod faunas of Albian age known to date, composed of a population of adult and juvenile crabs and lobsters. The peculiar small size of the individual lobsters of this fauna is attributed to their representing an early ontogenetic stage. No trace elements known to affect the biology an physiology of extant decapods could be found in the shale samples analyzed to indicate an environmental cause for the reduced size of the Pawpaw lobsters.</p>

No description available.

<p> The current biodiversity crisis is challenging the ability of conservation biologists to both monitor ongoing declines and create effective management plans. Ongoing habitat destruction, pollution, introduction of invasive species, and the initial stages of climate change are only some of the anthropogenic stresses that face today's biosphere. On human time scales, these changes are unprecedented, curtailing the availability of knowledge regarding ecological responses to stress and disturbance. The fossil record provides numerous disturbances of varying magnitudes throughout the history of life, and yet this resource has been often overlooked or dismissed by biologists. The purpose of this study is to examine the effects of stress on communities using methods that allow integration of modern and fossil data. With this goal in mind, various levels of disturbance are investigated across increasing temporal and spatial scales.</p><p> At the smallest spatial and temporal scale, I examined the effect of recent lake acidification on plankton communities, using techniques commonly applied by ecologists, as well as introducing a new method based on a well-established technique. Throughout this thesis, I use the Buzas-Gibson evenness metric and Non-metric Multi-Dimensional Scaling analysis (an ordination technique), as well as applying Rank-Abundance Curve Kurtosis, which measures the shape of species-abundance distributions. Each of these techniques is a different way of representing community structure, with each metric providing slightly different information. Within the lake acidification system, all communities displayed a shift in community structure as pH dropped, and again when pH values returned to neutral, indicating a gradual recovery from acid stress. The timing of this change reveals the ability of different communities to resist acidification, and the resilience of those communities through the recovery phase.</p><p> To determine the feasibility of comparing modern and fossil data, I selected four unrelated datasets with distinct disturbance events to represent different time scales, from two decades to one million years. Each dataset displayed a similar pattern; the disturbance event created a distinct shift in community structure followed by a gradual recovery after the stress levels decreased. A major concern when comparing modern and fossil data is the difference in temporal resolution, and specifically the effect of time-averaging which is expected to obscure ecological signals. Instead, I found that applying a model of time-averaging across the community data reduced background noise, thereby clarifying the pattern of ecological change observed in the raw data.</p><p> Extending the temporal and spatial scale, I explored the ecological response of marine microfossil assemblages during three intervals of rapid global warming, as analogues for modern global warming. Four taxonomic groups were included, two benthic and two planktic. Overall, diversity within communities increased during global warming, however this was due to the response of the planktic groups, as both benthic groups showed decreases in diversity. These findings support the utility of the fossil record in examining past disturbances, by providing a useful prediction for biotic responses to global warming.</p><p> Representing the largest spatial and temporal scale is the Botomian mass extinction (mid-Early Cambrian). This mass extinction is the first recognized mass extinction in the history of life, and occurred during an interval of rapid evolution and faunal turnover. During the extinction interval, there was a distinct change in community structure and an associated increase in instability.</p><p> The findings of this study are unique; community structure displays a similar response to stress across various taxonomic groups, in different environments, and at multiple temporal scales. The commonality in community response to stress likely represents a fundamental feature of disturbed ecosystems. Not only is the comparison of modern and fossil data possible, such comparisons offer new discoveries relevant to conservation biology and about the very nature of life on Earth.</p>

Thesis (Ph. D.)--University of Oregon, 2004. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 394-419). Also available for download via the World Wide Web; free to University of Oregon users.

Microwear analysis has been severely underutilized as a dietary technique due to numerous constraints involved in employing traditional scanning electron microscopy. A new methodology is described that greatly simplifies the assessment of microwear scar features for the discernment of the trophic adaptations of living and fossil taxa. A standard stereomicroscope and a fiber-optic light source have replaced specimen preparation tools such as venting and plating apparatus and the high-tech scanning electron microscope. Several new microwear variables supplement traditional quantification of pits and scratches. Significant niche partitioning in extant browsers, grazers, and mixed feeders is apparent and habitat differences within each broad trophic group are discernible by scoring relative pit sizes, scratch textures, and gouges in addition to quantifying scratches and pits. Variations in scratch number ranges, scratch textures, and relative pit sizes are the most useful variables for partitioning living ungulates into more refined trophic categories. Pit numbers and scratch textures are most effective for distinguishing fine versus coarse browsing, as well as leaf browsing versus fruit browsing. Scratch textural differences and scratch numbers distinguish fresh grass grazing versus coarse or mixed grass grazing; C3 versus C4 grazing, coarse bark and stem feeding, and seasonal or regional mixed feeding versus a meal-by-meal alternation between browse and grass. Heavy gouging is used to distinguish significant grit encroachment upon food items. Seasonal or regional mixed feeders have microwear that is more similar to browsers, whereas meal-by-meal mixed feeders have wear more similar to grazers. Three trophic phases are identified within extant ungulates by partitioning taxa into three potential raw scratch ranges: traditional browsing and grazing phases, comprised by surprisingly few species, and a browsing-to-grazing transitional phase where the majority of taxa are found, including all of the mixed feeders. The new microwear methodology is used to test two hypotheses regarding large shifts in dietary strategies in fossil ungulates from the North American Great Plains region: the supposed browsing-grazing transition in the fossil record of North American equids and the supposed shift to coarser browse in the fossil ruminant artiodactyl family known as the Dromomerycidae.

Thesis (M.Sc.) -- Memorial University of Newfoundland, 1987. / Typescript. Bibliography: leaves 135-155. Also available online.