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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
211

Lessons from Embryos: Haeckel's Embryo Drawings, Evolution, and Secondary Biology Textbooks

January 2014 (has links)
abstract: In 1997, developmental biologist Michael Richardson compared his research team's embryo photographs to Ernst Haeckel's 1874 embryo drawings and called Haeckel's work noncredible.Science soon published <&ldquo;>Haeckel's Embryos: Fraud Rediscovered,<&rdquo;> and Richardson's comments further reinvigorated criticism of Haeckel by others with articles in The American Biology Teacher, <&ldquo;>Haeckel's Embryos and Evolution: Setting the Record Straight <&rdquo;> and the New York Times, <&ldquo;>Biology Text Illustrations more Fiction than Fact.<&rdquo;> Meanwhile, others emphatically stated that the goal of comparative embryology was not to resurrect Haeckel's work. At the center of the controversy was Haeckel's no-longer-accepted idea of recapitulation. Haeckel believed that the development of an embryo revealed the adult stages of the organism's ancestors. Haeckel represented this idea with drawings of vertebrate embryos at similar developmental stages. This is Haeckel's embryo grid, the most common of all illustrations in biology textbooks. Yet, Haeckel's embryo grids are much more complex than any textbook explanation. I examined 240 high school biology textbooks, from 1907 to 2010, for embryo grids. I coded and categorized the grids according to accompanying discussion of (a) embryonic similarities (b) recapitulation, (c) common ancestors, and (d) evolution. The textbooks show changing narratives. Embryo grids gained prominence in the 1940s, and the trend continued until criticisms of Haeckel reemerged in the late 1990s, resulting in (a) grids with fewer organisms and developmental stages or (b) no grid at all. Discussion about embryos and evolution dropped significantly. / Dissertation/Thesis / Ed.D. Biology 2014
212

Professor Attitudes and Beliefs about Teaching Evolution

January 2014 (has links)
abstract: Teaching evolution has been shown to be a challenge for faculty, in both K-12 and postsecondary education. Many of these challenges stem from perceived conflicts not only between religion and evolution, but also faculty beliefs about religion, it's compatibility with evolutionary theory, and it's proper role in classroom curriculum. Studies suggest that if educators engage with students' religious beliefs and identity, this may help students have positive attitudes towards evolution. The aim of this study was to reveal attitudes and beliefs professors have about addressing religion and providing religious scientist role models to students when teaching evolution. 15 semi-structured interviews of tenured biology professors were conducted at a large Midwestern universiy regarding their beliefs, experiences, and strategies teaching evolution and particularly, their willingness to address religion in a class section on evolution. Following a qualitative analysis of transcripts, professors did not agree on whether or not it is their job to help students accept evolution (although the majority said it is not), nor did they agree on a definition of "acceptance of evolution". Professors are willing to engage in students' religious beliefs, if this would help their students accept evolution. Finally, professors perceived many challenges to engaging students' religious beliefs in a science classroom such as the appropriateness of the material for a science class, large class sizes, and time constraints. Given the results of this study, the author concludes that instructors must come to a consensus about their goals as biology educators as well as what "acceptance of evolution" means, before they can realistically apply the engagement of student's religious beliefs and identity as an educational strategy. / Dissertation/Thesis / Masters Thesis Biology 2014
213

Universal Biology

Mariscal, Carlos January 2014 (has links)
<p>Our only example of life is that of Earth- which is a single lineage. We know very little about what life would look like if we found evidence of a second origin. Yet there are some universal features of geometry, mechanics, and chemistry that have predictable biological consequences. The surface-to-volume ratio property of geometry, for example, places a maximum limit on the size of unassisted cells in a given environment. This effect is universal, interesting, not vague, and not arbitrary. Furthermore, there are some problems in the universe that life must invariably solve if it is to persist, such as resistance to radiation, faithful inheritance, and resistance to environmental pressures. At least with respect to these universal problems, some solutions must consistently emerge.</p><p> In this dissertation, I develop and defend my own account of universal biology, the study of non-vague, non-arbitrary, non-accidental, universal generalizations in biology. In my account, a candidate biological generalization is assessed in terms of the assumptions it makes. A successful claim is accepted only if its justification necessarily makes reference to principles of evolution and makes no reference to contingent facts of life on Earth. In this way, we can assess the robustness with which generalizations can be expected to hold. I contend that using a stringent-enough causal analysis, we are able to gather insight into the nature of life everywhere. Life on Earth may be our single example of life, but this is merely a reason to be cautious in our approach to life in the universe, not a reason to give up altogether.</p> / Dissertation
214

Religious Women’s Modest Dress as a Signal to Other Women

January 2020 (has links)
abstract: The present study tested the hypothesis that women dress modestly to signal to other women that they pose no mate poaching threat and are sexually restricted, and that this is especially true for religious women. Participants were 392 Muslim women living in the United States. They read two passages describing fictional situations in which they met with a potential female friend and then indicated what kind of outfit they would wear in both situations. In one situation, the participant obtained a reputation for promiscuity; in the other situation, reputation was not mentioned. I predicted that participants would choose more modest outfits for the promiscuous reputation passage, because if women dress modestly to signal sexual restrictedness, then they should dress more modestly around women with whom they have a reputation for promiscuity—to counteract such a reputation, women may wish to send a strong signal that they are not promiscuous. The hypothesis was partially supported: Less religious women chose more modest outfits for the promiscuous reputation situation than they did for the no reputation situation. This suggests that some women dress modestly to signal sexual restrictedness to other women, but that this is especially true for women who are less religious, not more. More religious women dress more modestly than less religious women, but they may not dress modestly to signal sexual restrictedness. Two important goals for this area of research are to determine the proximate reasons that more religious women dress modestly and to investigate modest dress among non-Muslim religious women. / Dissertation/Thesis / Doctoral Dissertation Psychology 2020
215

Systematics, Morphology, and Evolution of the New World Conoderinae Schoenherr, 1833 (Coleoptera: Curculionidae)

January 2019 (has links)
abstract: Weevils are one of the most diverse groups of animals with thousands of species suspected to remain undiscovered. The Conoderinae Schoenherr, 1833 are no exception, being especially diverse and unknown in the Neotropics where they are recognizable for their unique behaviors and color patterns among weevils. Despite these peculiarities, the group has received little attention from researchers in the past century, with almost nothing known about their evolution. This dissertation presents a series of three studies that begin to elucidate the evolutionary history of these bizarre and fascinating weevils, commencing with an overview of their biology and classificatory history (Chapter 1). Chapter 2 presents the first formal cladistic analysis on the group to redefine the New World tribes Lechriopini Lacordaire, 1865 and Zygopini, Lacordaire, 1865. An analysis of 75 taxa (65 ingroup) with 75 morphological characters yielded six equally parsimonious trees and synapomorphies that are used to reconstitute the tribes, resulting in the transfer of sixteen genera from the Zygopini to the Lechriopini and four generic transfers out of the Lechriopini to elsewhere in the Conoderinae. Chapter 3 constitutes a taxonomic revision of the genus Trichodocerus Chevrolat, 1879, the sole genus in the tribe Trichodocerini Champion, 1906, which has had an uncertain phylogenetic placement in the Curculionidae but has most recently been treated in the Conoderinae. In addition to redescriptions of the three previously described species placed in the genus, twenty-four species are newly described and an identification key is provided for all recognized species groups and species. Chapter 4 quantitatively tests the similarity in color pattern among species hypothesized to belong to several different mimicry complexes. The patterns of 160 species of conoderine weevils were evaluated for 15 categorical and continuous characters. Non-metric multidimensional scaling (NMDS) is used to visualize similarity by the proximity of individual species and clusters of species assigned to a mimicry complex in ordination space with clusters being statistically tested using permutational multivariate analysis of variance (PERMANOVA). / Dissertation/Thesis / Doctoral Dissertation Evolutionary Biology 2019
216

Life History Affects Cancer Gene Copy Numbers in Mammalian Genomes

January 2019 (has links)
abstract: Cancer is a disease which can affect all animals across the tree of life. Certain species have undergone natural selection to reduce or prevent cancer. Mechanisms to block cancer may include, among others, a species possessing additional paralogues of tumor suppressor genes, or decreasing the number of oncogenes within their genome. To understand cancer prevention patterns across species, I developed a bioinformatic pipeline to identify copies of 545 known tumor suppressor genes and oncogenes across 63 species of mammals. I used phylogenetic regressions to test for associations between cancer gene copy numbers and a species’ life history. I found a significant association between cancer gene copies and species’ longevity quotient. Additional paralogues of tumor suppressor genes and oncogenes is not solely dependent on body size, but rather the balance between body size and longevity. Additionally, there is a significance association between life history traits and genes that are both germline and somatic tumor suppressor genes. The bioinformatic pipeline identified large tumor suppressor gene and oncogene copy numbers in the naked mole rat (Heterocephalus glaber), armadillo (Dasypus novemcinctus), and the two-fingered sloth (Choloepus hoffmanni). These results suggest that increased paralogues of tumor suppressor genes and oncogenes are these species’ modes of cancer resistance. / Dissertation/Thesis / Pipeline results for cancer genes / Phylogenetic regressions with correction tests / Pipeline results for housekeeping genes / Masters Thesis Biology 2019
217

Female Orgasm and Women's Sexual Regret in the Context of One-Time Sexual Encounters

Jackson, Adam 01 June 2022 (has links)
No description available.
218

Promoter Identification in Daphnia Populations Revealed by Transcription Start Site Profiling

January 2020 (has links)
abstract: Regulation of transcription initiation is a critical factor in the emergence of diverse biological phenotypes, including the development of multiple cell types from a single genotype, the ability of organisms to respond to environmental cues, and the rise of heritable diseases. Transcription initiation is regulated in large part by promoter regions of DNA. The identification and characterization of cis-regulatory regions, and understanding how these sequences differ across species, is a question of interest in evolution. To address this topic, I used the model organism Daphnia pulex, a well-characterized microcrustacean with an annotated genome sequence and selected a distribution of well-defined populations geographically located throughout the Midwestern US, Oregon, and Canada. Using isolated total RNA from adult, female Daphnia originating from the selected populations as well as a related taxon, Daphnia pulicaria (200,000 years diverged from D. pulex), I identified an average of over 14,000 (n=14,471) promoter regions using a novel transcription start site (TSS) profiling method, STRIPE-seq. Through the identification of sequence architecture, promoter class, conservation, and transcription start region (TSR) width, of cis-regulatory regions across the aforementioned Daphnia populations, I constructed a system for the study of promoter evolution, enabling a robust interpretation of promoter evolution in the context of the population-genetic environment. The methodology presented, coupled with the generated dataset, provides a foundation for the study of the evolution of promoters across both species and populations. / Dissertation/Thesis / Masters Thesis Molecular and Cellular Biology 2020
219

Characterization of the CPI-17 Gene Family in Danio rerio

Virk, Guneet Kaur 01 January 2016 (has links)
Regulation of smooth muscle contraction depends on the phosphorylated state of myosin light chain (MLC). Although there are many kinases responsible for phosphorylating MLC, the myosin phosphatase complex is solely accountable for its dephosphorylation. Myosin phosphatase, in turn, is tightly regulated by many proteins. One of them being the CPI-17 gene family, which inhibits myosin phosphatase. This family of proteins is composed of CPI-17 itself, PHI-1, KEPI, and GBPI. Zebrafish have two genes each of CPI-17 and PHI-1, which are expressed during early embryonic development. This study sets out to investigate whether the two isoforms of CPI-17 and PHI-1 have diverged in function or expression using zebrafish as a model organism. Through a series of biochemical tests and assays, we have determined that the two isoforms have diverged in their expression pattern from each other, however they have similar function.
220

Molecular Phylogenetic Analysis of Argynnis Fabricius (1807) including North American Speyeria Scudder (1872)

de Moya, Robert S. 01 January 2016 (has links)
North American Speyeria butterflies are a group whose species hypotheses are confounded by shared wing color patterns between sympatric populations of closely related recognized species due to a putatively recent origin in evolutionary time. Previous studies of this group and the closely related Palearctic genus Argynnis , suggest that Speyeria is monophyletic but derived from within Argynnis . Sampling in these studies has either involved few basal Speyeria species, or too few Argynnis species (Simonsen 2006, Simonsen et al. 2006). Thus, no comprehensive phylogenetic analysis exists for all members that answers the question of monophyly of Speyeria , or other subgeneric taxa,and their relationship to Argynnis species. A phylogenetic analysis was completed of all North American Speyeria species and nearly all species within Argynnis , using one mitochondrial (CO1) and four nuclear genes (EF1?, WG, GAPDH, and RPS5). The results indicate that North American Speyeria is a monophyletic group, but that Palearctic Argynnis is paraphyletic. Three major lineages are identified within Argynnis sensu lato : two Palearctic and one containing both Palearctic and Nearctic species. Argynnis species representing the subgenera Argyreus , Argyronome , Childrena , Damora , Pandoriana , and Nephargynnis , belong to a well-supported lineage that split early in the evolution of the group and is comprised of species with long branches. Fabriciana and Mesoacidalia were both recovered as strongly supported lineages, except for A. clara which was recovered as sister to Speyeria . In summary, the phylogenetic analyses suggest the need for reorganization into three genera: Argynnis , Fabriciana , and Speyeria . The results have implications for the conservation of these butterflies across the temperate zone by providing a framework for understanding potential gene flow between sympatric species complexes, proper taxonomic validity, and the natural history of threatened populations of Speyeria and Argynnis butterflies.

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