Matching Items (153)
Description
The Cape Floral Region (CFR) in southwestern South Africa is one of the most diverse in the world, with >9,000 plant species, 70% of which are endemic, in an area of only ~90,000 km2. Many have suggested that the CFR's heterogeneous environment, with respect to landscape gradients, vegetation, rainfall, elevation, and soil fertility, is responsible for the origin and maintenance of this biodiversity. While studies have struggled to link species diversity with these features, no study has attempted to associate patterns of gene flow with environmental data to determine how CFR biodiversity evolves on different scales. Here, a molecular population genetic data is presented for a widespread CFR plant, Leucadendron salignum, across 51 locations with 5-kb of chloroplast (cpDNA) and 6-kb of unlinked nuclear (nuDNA) DNA sequences in a dataset of 305 individuals. In the cpDNA dataset, significant genetic structure was found to vary on temporal and spatial scales, separating Western and Eastern Capes - the latter of which appears to be recently derived from the former - with the highest diversity in the heart of the CFR in a central region. A second study applied a statistical model using vegetation and soil composition and found fine-scale genetic divergence is better explained by this landscape resistance model than a geographic distance model. Finally, a third analysis contrasted cpDNA and nuDNA datasets, and revealed very little geographic structure in the latter, suggesting that seed and pollen dispersal can have different evolutionary genetic histories of gene flow on even small CFR scales. These three studies together caution that different genomic markers need to be considered when modeling the geographic and temporal origin of CFR groups. From a greater perspective, the results here are consistent with the hypothesis that landscape heterogeneity is one driving influence in limiting gene flow across the CFR that can lead to species diversity on fine-scales. Nonetheless, while this pattern may be true of the widespread L. salignum, the extension of this approach is now warranted for other CFR species with varying ranges and dispersal mechanisms to determine how universal these patterns of landscape genetic diversity are.
ContributorsTassone, Erica (Author) / Verrelli, Brian C (Thesis advisor) / Dowling, Thomas (Committee member) / Cartwright, Reed (Committee member) / Rosenberg, Michael S. (Committee member) / Wojciechowski, Martin (Committee member) / Arizona State University (Publisher)
Created2013
Description
Understanding the diversity, evolutionary relationships, and geographic distribution of species is foundational knowledge in biology. However, this knowledge is lacking for many diverse lineages of the tree of life. This is the case for the desert stink beetles in the tribe Amphidorini LeConte, 1862 (Coleoptera: Tenebrionidae) – a lineage of arid-adapted flightless beetles found throughout western North America. Four interconnected studies that jointly increase our knowledge of this group are presented. First, the darkling beetle fauna of the Algodones sand dunes in southern California is examined as a case study to explore the scientific practice of checklist creation. An updated list of the species known from this region is presented, with a critical focus on material now made available through digitization and global aggregation. This part concludes with recommendations for future biodiversity checklist authors. Second, the psammophilic genus Trogloderus LeConte, 1879 is revised. Six new species are described, and the first, multi-gene phylogeny for the genus is inferred. In addition, historical biogeographic reconstructions along with novel hypotheses of speciation patterns within the Intermountain Region are given. In particular, the Kaibab Plateau and Kaiparowitz Formation are found to have promoted speciation on the Colorado Plateau. The Owens Valley and prehistoric Bouse Embayment are similarly hypothesized to drive species diversification in southern California. Third, a novel phylogenomic analysis for the tribe Amphidorini is presented, based on 29 de novo partial transcriptomes. Three putative ortholog sets were discovered and analyzed to infer the relationships between species groups and genera. The existing classification of the tribe is found to be highly inadequate, though the earliest-diverging relationships within the tribe are still in question. Finally, the new phylogenetic framework is used to provide a genus-level revision for the Amphidorini, which previously contained six valid genera and 253 valid species. This updated classification includes more than 100 taxonomic changes and results in the revised tribe consisting of 16 genera, with three being described as new to science.
ContributorsJohnston, Murray Andrew (Author) / Franz, Nico M (Thesis advisor) / Cartwright, Reed (Committee member) / Taylor, Jesse (Committee member) / Pigg, Kathleen (Committee member) / Arizona State University (Publisher)
Created2018
Description
The El Niño Southern Oscillation (ENSO) consists of a linkage between changes in sea-surface temperatures and atmospheric pressure across the Tropical Pacific. ENSO encompasses three phases: neutral events, warm/El Niño events in which sea-surface temperatures are warmer-than-normal and the pressure gradient decreases across the Equatorial Pacific, and cold/La Niña events in which Tropical Pacific sea-surface temperatures are cooler-than-normal and the pressure gradient increases. Previous studies have determined a connection between variations in ENSO phase and weather patterns across the globe, focusing particularly on surface temperature and precipitation patterns in the United States. However, little research exists that attempts to link changes in ENSO phase with severe weather in Arizona. Therefore, in this study, I analyzed how variations in ENSO phase affect the frequency, intensity, and spatial distribution of four types of severe weather from 1959 to 2016 in Arizona, including a) tornado events, b) severe thunderstorm wind events, c) hail events, and d) heavy rain and flash flood events. I collected data on the Oceanic Niño Index (ONI), a measure of ENSO, as well as storm reports for each severe weather phenomenon dating back to 1959. Then, I analyzed the frequency of each Arizona severe weather event type within each of the twelve annual months and over the entire study period. I also analyzed mean intensity values (Fujita/Enhanced Fujita Scale rating, path width, and path length for tornadoes; hail diameter in millimeters for hail; and wind gust speed for severe thunderstorm wind events) for each severe weather phenomenon, excluding the heavy rain and flash flood events. Finally, I used the Mean Center and Directional Distribution tools in ArcGIS to determine variations in the spatial distribution and mean centers between each ENSO phase for each severe weather event type. I found that ENSO phase, particularly La Niña, does impact the frequency and intensity of tornadoes, hail, thunderstorm wind, and heavy rain/flash flood events in Arizona. However, it appears that ENSO does not affect the spatial distribution of these Arizona severe weather phenomena. These findings attempt to fill in the gap in the literature and could help meteorologists better forecast changes in Arizona severe weather, in turn allowing Arizonans to better prepare for and mitigate the effects of severe weather across the state.
ContributorsGreenwood, Trey Austin (Author) / Cerveny, Randall (Thesis director) / Balling, Robert (Committee member) / School of Geographical Sciences and Urban Planning (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Triops (Branchiopoda: Notostraca) and Streptocephalus (Branchiopoda: Anostraca) are two crustaceans which cohabitate in ephemeral freshwater pools. They both lay desiccation resistant eggs that disperse passively to new hydrologically isolated environments. The extent of genetic distance among regions and populations is of perennial interest in animals that live in such isolated habitats. Populations in six natural ephemeral pool habitats located in two different regions of the Sonoran Desert and a transition area between the Sonoran and Chihuahuan Deserts were sampled. Sequences from Genbank were used for reference points in the determination of species as well as to further identify regional genetic distance within species. This study estimated the amount of within and between genetic distance of individuals from each region and population through the use of a neutral marker, cytochrome oxidase I (COI). We concluded that, although the method of passive dispersal may differ between the two genera, the differences do not results in different patterns of genetic distances between regions and populations. Furthermore, we only found the putative species, Triops longicaudatus "short", with enough distinct speciation. Although Triops longicaudatus "long" and Triops newberryi may be in the early stages of speciation, this study does not find enough support to conclude that they have separated.
ContributorsMurphy Jr., Patrick Joseph (Author) / Rutowski, Ronald (Thesis director) / Cartwright, Reed (Committee member) / Lessios, Nikos (Committee member) / School of Life Sciences (Contributor) / School of Human Evolution and Social Change (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Food’s implication on culture and agriculture challenges agriculture’s identity in the age of the city. As architect and author Carolyn Steel explained, “we live in a world shaped by food, and if we realize that, we can use food as a powerful tool — a conceptual tool, design tool, to shape the world differently. It triggers a new way of thinking about the problem, recognizing that food is not a commodity; it is life, it is culture, it’s us. It’s how we evolved.” If the passage of food culture is dependent upon the capacity for learning and transmitting knowledge to succeeding generations, the learning environments should reflect this tenability in its systematic and architectural approach.
Through an investigation of agriculture and cuisine and its consequential influence on culture, education, and design, the following project intends to reconceptualize the learning environment in order facilitate place-based practices. Challenging our cognitive dissonant relationship with food, the design proposal establishes a food identity through an imposition of urban agriculture and culinary design onto the school environment. Working in conjunction with the New American University’s mission, the design serves as a didactic medium between food, education, and architecture in designing the way we eat.
Through an investigation of agriculture and cuisine and its consequential influence on culture, education, and design, the following project intends to reconceptualize the learning environment in order facilitate place-based practices. Challenging our cognitive dissonant relationship with food, the design proposal establishes a food identity through an imposition of urban agriculture and culinary design onto the school environment. Working in conjunction with the New American University’s mission, the design serves as a didactic medium between food, education, and architecture in designing the way we eat.
ContributorsBone, Nicole (Author) / Rocchi, Elena (Thesis director) / Hejduk, Renata (Committee member) / Robert, Moric (Committee member) / The Design School (Contributor) / School of Geographical Sciences and Urban Planning (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
Protest has been both a practice of citizenship rights as well as a means of social pressure for change in the context of Mexico City's water system. This paper explores the role that citizen protest plays in the city's response to its water challenges. We use media reports of water protests to examine where protests happen and the causes associated with them. We analyze this information to illuminate socio-political issues associated with the city's water problems, such as political corruption, gentrification, as well as general power dynamics and lack of transparency between citizens, governments, and the private businesses which interact with them. We use text analysis of newspaper reports to analyze protest events in terms of the primary stimuli of water conflict, the areas within the city more prone to conflict, and the ways in which conflict and protest are used to initiate improved water management and to influence decision making to address water inequities. We found that water scarcity is the primary source of conflict, and that water scarcity is tied to new housing and commercial construction. These new constructions often disrupt water supplies and displace of minority or marginalized groups, which we denote as gentrification. The project demonstrates the intimate ties between inequities in housing and water in urban development. Key words: Conflict, protest, Mexico City, scarcity, new construction
ContributorsFlores, Shalae Alena (Author) / Eakin, Hallie C. (Thesis director) / Baeza-Castro, Andres (Committee member) / Lara-Valencia, Francisco (Committee member) / School of Geographical Sciences and Urban Planning (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
Many bacteria actively import environmental DNA and incorporate it into their genomes. This behavior, referred to as transformation, has been described in many species from diverse taxonomic backgrounds. Transformation is expected to carry some selective advantages similar to those postulated for meiotic sex in eukaryotes. However, the accumulation of loss-of-function alleles at transformation loci and an increased mutational load from recombining with DNA from dead cells create additional costs to transformation. These costs have been shown to outweigh many of the benefits of recombination under a variety of likely parameters. We investigate an additional proposed benefit of sexual recombination, the Red Queen hypothesis, as it relates to bacterial transformation. Here we describe a computational model showing that host-pathogen coevolution may provide a large selective benefit to transformation and allow transforming cells to invade an environment dominated by otherwise equal non-transformers. Furthermore, we observe that host-pathogen dynamics cause the selection pressure on transformation to vary extensively in time, explaining the tight regulation and wide variety of rates observed in naturally competent bacteria. Host-pathogen dynamics may explain the evolution and maintenance of natural competence despite its associated costs.
ContributorsPalmer, Nathan David (Author) / Cartwright, Reed (Thesis director) / Wang, Xuan (Committee member) / Sievert, Chris (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Mammary gland development in humans during puberty involves the enlargement of breast tissue, but this is not true in non-human primates. To identify potential causes of this difference, I examined variation in substitution rates across genes related to mammary development. Genes undergoing purifying selection show slower-than-average substitution rates, while genes undergoing positive selection show faster rates. These may be related to the difference between humans and other primates. Three genes were found to be accelerated were FOXF1, IGFBP5, and ATP2B2, but only the latter one was found in humans and it seems unlikely that it would be related to the differences between mammary gland development at puberty between humans and non-human primates.
ContributorsArroyo, Diana (Author) / Cartwright, Reed (Thesis director) / Wilson Sayres, Melissa (Committee member) / Schwartz, Rachel (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Since the start of U.S. hostilities against Iraq in 2003, International Relations scholars have begun to characterize the U.S. as potentially an empire. This is because the traditional notion of sovereignty under the Westphalian nation-state system is held as a constant in the prominent theories that govern how it is thought how nation-states interact with each other. The blatant violation of international laws and norms with impunity by the U.S. have led to a re-questioning of the true dynamics underlying this system. Some scholars have characterized the recent research as a popular fad, but most of the research is aimed at just attempting to show how the U.S. could be an empire. What the current research is missing is how the U.S. became an empire, with that analysis anchored in an historical comparison. A complete chronological review of each system in its entirety is required, with all of its components, to more fully understand these phenomena. This has required researchers to devise a new methodological process of qualitatively and quantitatively analyzing macro structures. We believe the implications of the insights that can be obtained with this new method could be of use to many fields and can generate many new hypotheses to test in the future.
ContributorsRoche, Joshua Nathan (Author) / Crittenden, Jack (Thesis director) / Walker, Stephen (Committee member) / Barrett, The Honors College (Contributor) / Economics Program in CLAS (Contributor) / School of Geographical Sciences and Urban Planning (Contributor) / School of Politics and Global Studies (Contributor)
Created2014-12
Description
"The Legal Adventures of Frankie and Rosie" is a creative project that explores the nontraditional format of comics to express creative nonfiction. The project is a set of 30 independent comics that focuses on two primary college-going students who are based off of the authors. The characters, Frankie and Rosie narrate their stories through dialogue. The authors use this narrative model to archive their college experience at ASU. Representing creative nonfiction through comics yields an amalgamated format that can be challenging for both the writers to produce as well as for the readers to consume. Ultimately, the project serves as an attempt to test whether or not the comic medium can stand by itself as an appropriate format to express creative nonfictional narratives without becoming a diluted combination of its purer predecessors.
ContributorsBennewitz, Dana (Co-author) / Ray, Payel (Co-author) / Martin, Thomas (Thesis director) / Scott Lynch, Jacquelyn (Committee member) / Civil, Environmental and Sustainable Engineering Programs (Contributor) / Barrett, The Honors College (Contributor) / School of Geographical Sciences and Urban Planning (Contributor) / Electrical Engineering Program (Contributor) / School of Social Transformation (Contributor) / School of Mathematical and Statistical Sciences (Contributor)
Created2015-05