No description available.

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Thesis (Ph. D.)--Johns Hopkins University, 1892. / Life. Reprinted from the Publications of the Modern Language Association of America, vol. X, no. 1. Bibliography: p. 12-16.

Thesis (Ph. D.)--University of Delaware, 2008. / Principal faculty advisor: George R. Parsons, College of Marine & Earth Studies. Includes bibliographical references.

No description available.

Hybridization, the process of interbreeding between individuals of different species, is one method by which plants and animals adapt to a changing environment. One example of such adaptation through hybridization may be occurring on the California Channel Islands with two species of Castilleja. While United State Geological Survey (USGS) researchers have been studying the populations of Castilleja affinis and Castilleja mollis to determine if hybridization is occurring on Santa Rosa Island since the early 1990s, up until this point primarily overt phenotypic characteristics have been used to differentiate between the two species. Genetic methods of differentiation were adopted to confirm that hybridization is in fact occurring on the island, possibly in response to climate change. Hybrids may be expanding into areas once occupied by pure C. mollis, because they might carry some of C. affinis’ traits like an ability to survive warmer, drier climates as parts of the island are starting to become warmer and drier. In this study, I have developed a cleaved amplified polymorphic sequences (CAPS) marker based on internal transcribed spacer (ITS) regions to differentiate between the two species and hybrids and have applied these CAPS markers to genotype DNA samples isolated from 132 individuals. This protocol was used to determine the extent of hybridization on Santa Rosa Island in conjunction with ongoing surveys conducted by the USGS. Work focused on genotyping previously collected samples from two main sites on the island, which allowed confirmation that patterns observed based on phenotype in the field are supported by genetic data. In the future, findings will link genetic type with survivorship and growth data, to test whether hybrids perform differently than pure C. mollis. Broadly, this will determine if the two species are in fact hybridizing as a method for adapting to climate change, the most severe threat to Channel Island biodiversity.

Although it has long been portrayed as the nation’s ‘moat defensive’, recent examinations of Anglo-French rivalry during the long eighteenth century have revealed that the English Channel was, in reality, a highly permeable and vulnerable maritime border territory. Within this context, the Channel Islands assumed a strategic and tactical significance which was vastly disproportionate to their physical size, population or resources; emerging as what Morieux terms ‘a lynchpin of control' over local shipping and trade. Although a great deal of research has been already undertaken – particularly in relation to the Channel Islands’ role as a base for commerce-raiding and intelligence gathering – much of this has covered the entire long eighteenth century. However, it was only during the Great French War that the British government embraced the military potential of the Channel Islands to the fullest; not only exploiting the inhabitants’ knowledge of the seas and intimacy with her ‘enemies’, but also transforming the archipelago into a chain of offshore fortresses. In addition, prior scholarship has often focused on individual aspects of the Channel Islands’ involvement in the Great French War; while local historians have tended to embrace the ‘Great Man’ approach, examining the period through the lens of the careers of local commanders. Consequently, this thesis seeks to provide a more complete picture of the Channel Islands’ role within Britain’s military and naval strategy; integrating an examination of local defence and security with several of already well-covered topics. Moreover, in light of the fact that existent scholarship has often centred upon ‘Great Men’, it is hoped that the thesis shall serve to better demonstrate the extent to which the celebrated achievements of Don, Doyle and D’Auvergne rested upon the efforts of a number of ‘unsung heroes’.

I looked at the restoration of Santa Cruz Island National Park to examine the interconnected relationship between nature and culture in the United States. I conducted literature research on the changes in conceptual construction and environmental policy, and grounded my analysis in interviews I conducted with National Park Employees involved in the Primary Restoration Plan. Through the language of their responses, I analyzed how specific words, process and possibility, affect the restoration and consequently our concept of nature.

<p>Islands have been the inspiration for some of evolutionary biology's most important advances. This is largely due to the unique properties of islands that promote the differentiation of island species from their mainland counterparts. Rodents are widely distributed across even the most remote islands, a rarity among mammals, making them uniquely suited to study the factors leading to the divergence of insular species. In this dissertation, I use two case studies to examine the morphological and genetic divergences that take place in an insular environment.</p><p>In chapters one and two, I examine how different factors influence insular body size change in rodents. In chapter one, I examine factors influencing the direction of island body size change using classification tree and random forest (CART) analyses. I observe strong consistency in the direction of size change within islands and within species, but little consistency at broader taxonomic scales. Including island and species traits in the CART analyses, I find mainland body mass to be the most important factor influencing size change. Other variables are significant, though their roles seem to be context-dependent.</p><p>In chapter two, I use the distributions of mainland rodent population body sizes to identify `extreme' insular rodent populations and compare traits associated with those populations and their islands with those island populations of a more typical size. I find that althought there is no trend among all insular rodents towards a larger or smaller size, `extreme' populations are more likely to increase in size. Using CART methods, I develop a predictive model for insular size change that identifies resource limitations as the main driver when insular rodent populations become `extremely small'. </p><p>Chapters three and four shift their focus to a single rodent species, the deer mouse <italic>Peromyscus maniculatus</italic>, as they examine the genetic differentiation of deer mice across the California Channel Islands and the nearby mainland. In chapter three, I sequence a region of the mitochondrial control region for individuals from 8 populations across the northern Channel Islands and two mainland sites, and I analyze these sequences by calculating population genetics parameters and creating a Bayesian inference tree and a statistical parsimony haplotype network. All of these analyses reveal significant divergences between island and mainland populations. Among the islands, Santa Barbara and Anacapa islands both display unique genetic signatures, but the other northern islands remain relatively undifferentiated.</p><p>In chapter four, I genotype individuals from the previous chapter at 5 microsatellite loci, I calculate additional population genetics parameters and I utilize a Bayesian clustering algorithm to examine the similarities and differences between nuclear and mitochondrial analyses. I find the nuclear data to be largely congruent with the mitochondrial analyses; there are significant differences between island and mainland populations, and Anacapa Island is significantly differentiated from the other islands. Unlike the previous analyses, Santa Barbara Island is not significantly different from the northern islands, yet San Miguel Island has a unique genetic signature. </p><p>These studies underscore the importance of ecological processes and historical biogeography in the generation of diversity, and they highlight the role of islands as drivers of evolutionary divergence.</p> / Dissertation