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.
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Showing 1 to 20 of 267 for “"natural selection"”.
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Natural Selection
My thesis work is about imagination. I use the collaborative efforts of the viewer's mind and my sculptures, or specimens, to make associations of real life animals. I feel this engages the viewer and in turn invites them to inspect the work on closer level. This is my ultimate goal in the work, to …
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Natural Selection Reconsidered
… which tend to underpin mainstream accounts of natural selection, noting where those assumptions break down and taking this as a basis for fresh analysis. First, I examine the assumption that natural selection inherently involves struggle or competition. I show selection can take place without …
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Natural selection successfully taught
"Natural selection, one of biology's most important concepts, has proven vexing to both teach and learn. Polanyi's concept of tacit knowledge and Broudy's concept of ""knowing with"" served as the basis for developing materials to teach natural selection. These materials sought to make explicit to …
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Natural Selection on S-Linked Genes in Turnera (Passifloracease)
… were adopted to explore the signatures of selection on S-linked genes in distylous Turnera. While dN/dS-based results revealed pervasive purifying selection at the S-locus in Turnera, average nucleotide diversity and sequence polymorphism measures were found to be elevated in two S-linked …
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Quantifying evolution and natural selection in vertebrate noncoding sequence
… it important to identify varying patterns of natural selection. Many traditional methods of classifying directional selection have relied on models that categorize mutations as function-altering or neutral, and then comparing the rates of the two categories of mutations. The most well-known …
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Human population history and its interplay with natural selection
… have important consequences on the dynamics of natural selection and our ability to detect it. In this thesis, I aimed to refine our knowledge on human population history using ancient genomes, and then used a climate-informed, spatially explicit framework to explore the interplay between …
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The effects of natural selection on human Y chromosome amplicons
… of functional genes, speculation abounded that natural selection is ineffective on a chromosome that lacks a homolog with which to recombine, and that the Y chromosome is doomed to eventually fade away. In recent years, evidence has been building that the Y chromosome is indeed shaped by …
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1,000 ancient genomes uncover 10,000 years of natural selection in Europe
… years, allowing us to resolve the timing of selection into the Neolithic, Bronze Age, and Historical periods, and to identify 25 loci with evidence of rapid changes in allele frequency during these periods. All 10 candidate loci in the Historical period were detected in previous scans, with …
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Geographic variation and natural selection in Eumeces obsoletus (Reptilia: Sauria: Scincidae)
Thesis (M.A.)--University of Kansas, Department of Systematics and Ecology, 1975.
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Leveraging genetic time series data to improve detection of natural selection
<p>My work focuses on the problem of detecting natural selection from genetic time series data. This dissertation is motivated by genomic sequence data from populations of the Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) sampled temporally during the early stages of infection from …
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PATTERNS OF NATURAL SELECTION ASSOCIATED WITH TROPISM SHIFTS IN ANIMAL CORONAVIRUS GENOMES
… a variety of CoV viral sequences to identify how natural selection may alter viral proteins priming them for tropism shifts. Statistical codon models can infer both which codon sites and genes have been subject to positive or negative selection, effectively differentiating signal between random …
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Molecular Signatures of Adaptation: MHC Evolution and Natural Selection in European Rabbits
… challenges for tracking evolutionary changes in natural populations. The myxomatosis pandemic in European rabbits (Oryctolagus cuniculus) provides an unprecedented opportunity to examine MHC-I evolution under intense viral selection. Following the release of myxoma virus as a biological control …
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Estimating evolutionary parameters and detecting signals of natural selection from genetic data
… questions about human population differences, natural selection, and admixture. However, with this deluge of newly available data, confusion about statistical methods may lead to misleading conclusions about human population history and natural selection. We view it as imperative to put …
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Natural Selection and Natural Processes: a philosophical examination of the processes of evolution
… for their coherence and validity. Historically natural selection has been taken to be the central and main explanans, with other explanations playing lesser roles. Here it will be argued that the sheer complexity and diversity within nature cannot be accounted for by any single explanatory …
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Natural selection on MRNA secondary structure and its correlation with protein functional groups
Natural selection may occur at multiple levels of the biological hierarchy, including at the molecular level. It may occur on any phenotypic trait that evidences variation and that is heritable. This research uses computational methods to investigate whether the stability of the secondary …
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A SURVEY OF THE COMMON LOON (Gavia immer) GENOME REVEALS PATTERNS OF NATURAL SELECTION
… characterized—by finding signatures of positive selection as evidence for genomic adaptation.</p> <p>I used Illumina short read sequencing data from a single female common loon to produce a fragmented assembly of the common loon (<em>Gavia immer</em>) genome. The resulting assembly had a contig …
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Investigating Damage, Genetic Correlations, and Natural Selection to Understand Multiple Plant Defenses in Passiflora incarnata
… lead to compensatory changes in expression and selection on non-defense traits, such as floral traits. Natural selection could favor producing multiple defenses if synergism between defenses increases the benefits or decrease the costs of producing multiple defenses. Non-linear relationships …
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The genetic basis of pupal color dimorphism in Papilio polyxenes and its maintenance by natural selection
… reared from wild caught females. In addition a selection experiment was designed to investigate the genetic basis of the dimorphism. It was concluded that the genetic basis of the dimorphism is a threshold trait with quantitative genetic variation underlying the two phenotypes of green and brown …
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Signatures of natural selection and local adaptation in Populus trichocarpa and Populus deltoides along latitudinal clines
… trees. To better understand the possible role of natural selection on circadian clock-related genes in climatic adaptation, I took a candidate gene approach, selecting circadian clock genes, some of which had been functionally validated, and others hypothesized, to identify signatures of natural …
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