Evolution Commons^™

Applying Transcriptomics For Technology Development And Conservation In North American Marine Organisms, Cory Von Eiff

Dissertations

RNA biology is a rapidly expanding field, with many avenues of discovery among marine organisms. In this study, we analyze both mollusks and sawfish. First, we perform an evaluation of sRNA biogenesis pathways throughout Mollusca, with emphasis on the easter oyster, Crassostrea virginica. Understanding these molecules prescribes RNAi-based gene silencing approaches, benefiting genetic investigation and biotechnology. Similar to other animal groups, mollusks have conserved microRNAs (miRNAs), with some shared with ecdysozoans and deuterostomes; however, there is no evidence of an endogenous small interfering RNA (siRNA) pathway. These results suggest that long double-stranded RNA (dsRNA)-based RNAi is not appropriate for gene …

The Ecology And Evolution Of Species Rarity In Oaks (Quercus Spp.), Yingtong Wu

Dissertations

Rare species are susceptible to extinction due to ecological and genetic factors. Understanding the distribution, ecology, and evolution of rare species can provide useful information for effective conservation. To investigate species rarity, this dissertation focuses on a species-rich and ecologically diverse genus, Quercus (oaks). In Chapter 1, I aimed to understand how interactions between hosts and soil microbes contribute to habitat restriction in oak species. I performed a soil inoculum experiment on two pairs of sister oak species that show habitat divergence. I found that host-specific soil microbes contribute to habitat divergence and exclusion among sister species of oaks, but …

Characterizing Endogenous Dicer Products To Unravel Novel Rnai Biogenesis Pathways, Jacob Oche Peter

Dissertations

ABSTRACT

RNA interference (RNAi) is a pervasive gene regulatory mechanism in eukaryotes based on the action of multiple classes of small RNA (sRNA). Exploiting RNAi pathways in non-model systems have great potential for creating potent RNAi technologies. Here, we accessed RNAi-mediated control of gene expression in the two-spotted spider mite, Tetranychus urticae (T. urticae) using engineered dsRNA designed to modulate the host RNAi pathway and increase RNAi efficacy. Analysis of Dicer (Dcr) generated fragments revealed how exogenous RNAs access the host RNAi pathway in this animal, opening avenues for designing RNAi technology for their control. Further, some organisms …

The Role Of Zingiberales Shared Evolutionary History And Leaf Traits In Structuring Rolled-Leaf Beetle Assemblages In A Tropical Forest, José Miguel Chaves Fallas

Dissertations

Understanding how local assemblages of plants and animals are structured is a central challenge for evolutionary ecology. Tropical assemblages are high in species numbers and in variety of ecological interactions, providing unique multispecies biological systems to test ecological and evolutionary hypotheses about community assembly. The objective of this dissertation was to understand the role of Zingiberales shared evolutionary history and plant traits for structuring the rolled-leaf beetle (Cephaloleia and Chelobasis, Chrysomelidae) assemblage in a lowland wet forest (La Selva Biological Station) of Costa Rica.

In chapter I studied the evolution of physical, nutritional, and chemical leaf traits, how …

Investigating Drivers Of Genetic Structure In Plants: Global, Regional And Local Scales, Diana Gamba-Moreno

Dissertations

Genetic structure within and among plant populations is a critical component of plant biodiversity, informing local adaptation, conservation, and incipient speciation. However, its drivers remain poorly understood, especially across different spatial scales. In my dissertation I examined factors that affect plant population genetic structure at global, regional, and local scales. At the global scale, I performed a literature review of population genetic differentiation (F_ST) in seed plants based on a 337-species dataset with data on F_ST and species traits. Using phylogenetic multiple regressions, I found that F_ST is higher for tropical, mixed-mating, non-woody species pollinated by …

Evolution In Light Of Mitonuclear Landscapes: An Examination Of Mitochondrial Replacement In Killifish (Fundulus Spp.), Stephen D. Flanagan

Dissertations

The mitochondria are responsible for the bulk of energy production in eukaryotes. They possess their own genome that works in conjunction with the nuclear genome to accomplish the extraordinarily important task of energy conversion. When species hybridize there will be a mismatch in evolutionary histories between these two genomes. The deleterious interactions of these genomes have been studied in great detail (i.e. hybrid breakdown). However, little work has been conducted to understand the population genetic, and morphological consequences of wide-ranging replacement. The Fundulus notatus complex is comprised of 3 species: F. notatus, F. olivaceus, and F. euryzonus. …

Minority Middle And High School Students' Interest In Science: An Exploration Of Teachers' Perceptions, Caroline Makere

Dissertations

A high school teacher conducted a study about minority middle and high school students’ interest in science. The problem was to find out why African American and Hispanic students were showing very little interest in science. The researcher used four middle school science teachers and nine high school science teachers, all from inner city schools in a big city of the Midwest United States except for one middle school teacher from a nearby suburb. The participants answered a survey questionnaire followed with a face-to-face recorded interview. The findings of the study confirmed that students showed little interest in science due …

Analysis Of The Intricacies Of Substrate Recognition Of High Mobility Group Proteins And Aminoacyl-Trna Synthetases Using Non-Cognate Substrates, Douglas Van Iverson Ii

Dissertations

The studies presented in section 1 (Chapters I-IV) focus on the design and development of nucleic acid four-way junctions (4WJs) to target a member of the high mobility group (HMG) proteins, the proinflammatory cytokine high mobility group box 1 protein (HMGB1). In the present study, hybrid PNA-DNA 4WJs based on a model DNA 4WJ were constructed to improve the thermal stability of 4WJs while maintaining strong binding affinity toward HMGB1. An electrophoretic mobility shift assay (EMSA) was used to examine the binding affinity of an isolated DNA binding domain of HMGB1, the HMGB1 b-box (HMGB1b), toward a set of PNA-DNA …

Assessing The Impact Of Historical Story Telling On Student Learning Of Natural Selection, Janice Marie Fulford

Dissertations

Research suggests that because of its historical nature, the learning of evolutionary biology is problematic compared to that of other science disciplines. While explanations used in historical sciences often employ historical narratives, which are distinct from narratives in other contexts, such as stories, the two types of narratives have structural similarities that suggest the potential role of stories based in the history of science for the teaching of evolutionary biology. Stephen Klassen, a prominent science educator, has studied how stories from the history of physics can promote the learning of and attitudes towards science. Klassen’s pioneering work identifies structural components …

Moral Implications Of Darwinian Evolution For Human Reference Based In Christian Ethics: A Critical Analysis And Response To The "Moral Individualism" Of James Rachels, Stephen Bauer

Dissertations

The topic. This dissertation explores and analyzes James Rachels's efforts to prove that Darwin's theory of evolution has catastrophic implications for traditional Christian ethics.

The purpose. The purpose of this dissertation is to explore and evaluate the question of whether or not protology affects ethics. In particular, I propose to distill the implications of evolutionary views of origins for ethics, mainly in reference to the issue of human preference over nature in ethics. I propose to disclose Rachels's understanding of the implications of evolution on human preference (greater protections for human beings over non-humans) in ethics (such as biblical-Christian ethics), …

An Account Of Novice Phylogenetic Tree Construction From The Problem-Solving Research Tradition, Terrance E. Brisbin

Dissertations

Both the content and strategic knowledge used in phylogenetic tree construction are described to account for novice performance. A review of the literature is used to place this research with respect to studies in: problem solving studies (both expert, and novice), the history and practice of evolutionary systematics, and the teaching of evolution. The computer-based problem-solving environment is discussed along with model problems used for the research.

Each of the five research problems consists of an encoded matrix containing phylogenetic data organized by taxa and characters. Twelve participants (high school students) volunteered to solve the research problems, on their own …