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Ranging Behavior, Group Cohesiveness, And Patch Use In Northern Bearded Sakis (Chiropotes Sagulatus) In Guyana, Christopher Shaffer
Ranging Behavior, Group Cohesiveness, And Patch Use In Northern Bearded Sakis (Chiropotes Sagulatus) In Guyana, Christopher Shaffer
All Theses and Dissertations (ETDs)
I conducted a 15 month study of the activity patterns, diet, ranging behavior, and group cohesiveness of northern bearded sakis: Chiropotes sagulatus) in a continuous lowland rainforest in southern Guyana. My study combined observational data with a novel GIS-based method for assessing food patch quality to assess how bearded sakis adjusted their ranging and grouping patterns in response to changes in resource quality. My study group consisted of at least 65 animals, making it the largest group of Chiropotes yet reported. Bearded sakis were highly active, spending most of their time traveling: 40% of activity) and feeding: 35% of activity). …
The Evolution And Reproductive Ecology Of Oenothera (Onagraceae), Kyra Krakos
The Evolution And Reproductive Ecology Of Oenothera (Onagraceae), Kyra Krakos
All Theses and Dissertations (ETDs)
This dissertation describes the role of pollination in the floral diversification of Oenothera with an integration of both ecological and phylogenetic approaches. Oenothera: Onagraceae) is a model system for studying plant reproductive biology. It provides excellent examples of shifts in reproductive traits such as pollination and breeding system, features that have been important in angiosperm diversification. These systems are evolutionarily labile; they easily shift between different states. These different reproductive traits may shift in a concerted fashion; therefore, a more comprehensive approach to understanding the evolution of these plant systems simultaneously addresses shifts in pollination and breeding system. Using 54 …
Effects Of The Aquatic To Terrestrial Habitat Ratio On An Amphibian Predator And Its Prey, Amber Kramer
Effects Of The Aquatic To Terrestrial Habitat Ratio On An Amphibian Predator And Its Prey, Amber Kramer
All Theses and Dissertations (ETDs)
This dissertation explores the effects of varying the composition of aquatic and terrestrial habitats in a landscape: the aquatic to terrestrial ratio) on amphibians that use both the aquatic and terrestrial habitats during their lives. In Chapter 1, I first used meta-analysis and simulations to demonstrate that as the longevity of an amphibian increases, the elasticity of the population growth rate to perturbations in the aquatic: larval) habitat decreases. In Chapter 2, I examined the abundance of larvae of a long-lived amphibian, Ambystoma maculatum, across landscapes that varied in their aquatic to terrestrial ratios and found that larvae of this …
Dietary Shifts, Niche Relationships And Interspecific Competition In Sympatric Grey Langur (Semnopithecus Entellus) And Purple-Faced Langur (Trachypithecus Vetulus) In Sri Lanka, Rajnish Vandercone
Dietary Shifts, Niche Relationships And Interspecific Competition In Sympatric Grey Langur (Semnopithecus Entellus) And Purple-Faced Langur (Trachypithecus Vetulus) In Sri Lanka, Rajnish Vandercone
All Theses and Dissertations (ETDs)
Understanding how niche differences evolve in ecologically similar species and how these differences are maintained ecologically is a fundamental question in ecology. Interspecific competition has been shown to influence the behavior and ecology of organisms in a wide range of ecological communities. However, the broader role of interspecific competition in primate communities is unclear as relatively few studies have explored this question. This is especially true for folivorous primate communities, such as those of colobine monkeys, in which the influence of interspecific competition on aspects of the ecology of these monkeys is yet to be determined. In this dissertation, I …
Causes Of Rarity In Glade-Endemic Plants: Implications For Responses To Climate Change, Nicole Miller-Struttmann
Causes Of Rarity In Glade-Endemic Plants: Implications For Responses To Climate Change, Nicole Miller-Struttmann
All Theses and Dissertations (ETDs)
This dissertation documents the relationship between stress-adaptation and reproductive specialization in three endemic plant species: Delphinium treleasei, Echinacea paradoxa, and Scutellaria bushii) that are locally abundant but restricted to stressful habitats and their closely-related congeners: D. carolinianum, E. pallida, S. ovata, and S. parvula) that have broader habitat use, including hot, xeric habitats. In Chapter Two, I test two hypotheses concerning reproductive specialization in endemic plants and their common congeners: CC). I quantify morphological traits that are associated with stress-adaptation and reproductive specialization, pollinator behavior, and reproductive specialization. The locally abundant, habitat specialist: LAHS) species were significantly different from their …
Genetic And Phenotypic Differentiation Between Winemaking And Wild Strains Of Saccharomyces Cerevisiae, Katie Hyma
Genetic And Phenotypic Differentiation Between Winemaking And Wild Strains Of Saccharomyces Cerevisiae, Katie Hyma
All Theses and Dissertations (ETDs)
Traditionally, Saccharomyces cerevisiae has been associated with wine, beer and bread production, yet wild strains have also been isolated from natural habitats. While all strains of S. cerevisiae as well as other Saccharomyces species are capable of wine fermentation, a genetically distinct group of S. cerevisiae strains is primarily used to produce wine. These strains exhibit an apparent genetic bottleneck, which led to the hypothesis that wine stains have been domesticated from `wild' natural strains. However, it is unknown whether the genetic bottleneck was accompanied by selection for phenotypic differences. In this study we tested for phenotypes correlated with the …
The Effects Of Habitat Corridors And Edges On Sources Of Seed Mortality: Implications For Restoring A Threatened Legume, Melissa Simon
The Effects Of Habitat Corridors And Edges On Sources Of Seed Mortality: Implications For Restoring A Threatened Legume, Melissa Simon
All Theses and Dissertations (ETDs)
No abstract provided.
Functional Genomic Examinations Of Interactions Between Common Members Of The Human Gut Microbiota, Michael Mahowald
Functional Genomic Examinations Of Interactions Between Common Members Of The Human Gut Microbiota, Michael Mahowald
All Theses and Dissertations (ETDs)
The adult human gut microbiota consists of hundreds to thousands of bacterial species, the majority belonging to the Bacteroidetes and the Firmicutes. Differences in the balance between these phyla has been linked to obesity in mice and humans. However, little is known about their interactions in vivo. I have used comparative and functional genomics, proteomics and biochemical assays to identify the ways they marshal their genomic resources to adapt to life together in the distal gut. I first annotated the complete genome sequences of two human gut Bacteroidetes (Bacteroides vulgatus and Parabacteroides distasonis) and two Firmicutes (Eubacterium rectale and E. …
Inbreeding Depression And Competition In The Square-Stemmed Monkey-Flower (Mimulus Ringens), Nicholas Griffin
Inbreeding Depression And Competition In The Square-Stemmed Monkey-Flower (Mimulus Ringens), Nicholas Griffin
All Theses and Dissertations (ETDs)
Matings between biologically related individuals often produce offspring with reduced fitness, a phenomenon known as inbreeding depression. The magnitude of inbreeding depression can play an important role in determining the overall fitness, and persistence, of populations, and is often considered one of the key factors driving the evolution of mating systems and their associated traits. Recent research has shown that the strength of inbreeding depression is often highly sensitive to environmental conditions, such as the availability of abiotic resources or variation in the strengths of ecological interactions between organisms. In plant populations, drought, plant density, herbivory, and infection by pathogens, …
Historical And Geographic Context For The Evolution Of Climate Niche Breadth In Temperate Plants, Brad Oberle
Historical And Geographic Context For The Evolution Of Climate Niche Breadth In Temperate Plants, Brad Oberle
All Theses and Dissertations (ETDs)
In order to predict how species will respond to global climate change, scientists must understand the relationships between traits, fitness, environments and distributions. Niche theory provides a useful framework. Niche breadth describes the range of environmental conditions necessary for population growth. Among these conditions, climate is especially important. Climate niche breadth in turn may reflect a confluence of different forces. This dissertation presents a series of projects that assess the relative roles of historical, geographic and population processes that contribute to climate niche breadth in temperate plants. The first project evaluates the predictive power of a classical hypothesis. If gene …