Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 15 of 15
Full-Text Articles in Entire DC Network
Effect Of Climate History On The Genetic Structure Of An Antarctic Soil Nematode, Abigail C. Jackson
Effect Of Climate History On The Genetic Structure Of An Antarctic Soil Nematode, Abigail C. Jackson
Theses and Dissertations
Historical climate disturbances such as glacial cycling and fluctuating stream, lake, and sea levels strongly influence the distribution and evolutionary trajectories of Antarctic terrestrial species. Antarctic invertebrates, with limited long-range mobility, including the ubiquitous sentinel nematode species Scottnema lindsayae, are especially sensitive to climate disturbances. We tested hypotheses associated with the historical geographic and population genetic structure of this species as it occurs across the McMurdo Dry Valleys (MDVs) of Antarctica. In order to reconstruct the influence of climate disturbance and ecological conditions on this species, partial mitochondrial COI gene sequences were sequenced and analyzed from individual S. lindsayae collected …
The Development Of A Genomic Toolbox For Studying The Evolutionary Genetics Of Reptilian Lungs Using The Chicken Model, Logan Thomas Edvalson
The Development Of A Genomic Toolbox For Studying The Evolutionary Genetics Of Reptilian Lungs Using The Chicken Model, Logan Thomas Edvalson
Theses and Dissertations
There is a vast diversity in tetrapod lung branching morphology. Phylogenetically, much of the pulmonary diversity among vertebrates appears to arise from the way epithelial tubes branch or form saccular (cyst) structures. Fgf10 activity has been shown to play a critical role in regulating branch versus cyst morphology. We hypothesize that the species-specific differences in lung morphology may be primarily due to species-specific differences in Fgf10 expression. To test this hypothesis, we have performed bioinformatic analyses on the Fgf10 locus and have identified a conserved 11 kb noncoding region that potentially contains the Fgf10 lung enhancer. We are taking a …
Acceptance Finds A Way: How To Teach And Use Evolution's Explanatory Power, Daniel George Ferguson
Acceptance Finds A Way: How To Teach And Use Evolution's Explanatory Power, Daniel George Ferguson
Theses and Dissertations
The theory of evolution is the central combing theory that brings together all the tenets of biology that bring about a solid understanding of life. It is also one of the most controversial scientific theories of all time and is widely rejected by about 40% of the general public in the United States. One of the biggest reasons for low evolution acceptance is the perceived conflict between evolution and religious beliefs. Educators and researchers have been working hard to improve how we teach evolution in the classroom; some methods, such as focusing on evolution knowledge, have shown to be mixed. …
Comparative Sequence Analysis Elucidates The Evolutionary Patterns Of Yersinia Pestis In New Mexico Over Thirty-Two Years, M. Elizabeth Warren
Comparative Sequence Analysis Elucidates The Evolutionary Patterns Of Yersinia Pestis In New Mexico Over Thirty-Two Years, M. Elizabeth Warren
Theses and Dissertations
Yersinia pestis, a gram-negative bacterium, is the causative agent of plague. Y. pestis is a zoonotic pathogen that occasionally infects humans, and is endemic in the western United States. History gives evidence of three main plague pandemics. The first, originating in Egypt in 541AD, is known as the Justinian plague. The second, perhaps most well-known, is thought to have emerged in 1347AD in China, and is called the Black Death. The third, and current plague pandemic, also emerged in China in 1855. In 1899, Y. pestis was established in California, and the plague in other parts of America evolved from …
Evolution And Selection: From Suppression Of Metabolic Deficiencies To Bacteriophage Host Range And Resistance, Daniel Kurt Arens
Evolution And Selection: From Suppression Of Metabolic Deficiencies To Bacteriophage Host Range And Resistance, Daniel Kurt Arens
Theses and Dissertations
The evolution and adaptation of microorganisms is so rapid it can be seen in the time frame of days. The root cause for their evolution comes from selective environmental pressures that see organisms with beneficial mutations survive otherwise deadly encounters or outperform members of its population who fail to adapt. This does not always result in strict improvement of the individual as in the case of antibiotic resistant bacteria who often display fitness tradeoffs to avoid death (see Reviews [1-3]). For example, when an ampicillin resistance gene (ampC) containing plasmid that is occasionally found in the wild was transformed into …
Multispecies Character Displacement In Mexican Poeciliopsis Fishes, Andrea J. Roth
Multispecies Character Displacement In Mexican Poeciliopsis Fishes, Andrea J. Roth
Theses and Dissertations
Competition has long been recognized as a central force in shaping evolution, particularly through character displacement. Yet research on character displacement is biased as it has focused almost exclusively on pairs of interacting species while ignoring multispecies interactions. Unfortunately, communities are seldom so simple that only pairs of species interact, and it is not clear if inferences from pairwise interactions are sufficient to explain patterns in nature. A more realistic approach is to ask how traits evolve when multiple species interact. Here I explore the importance of multispecies competitive interactions on trait evolution in four congeneric species of livebearing fishes …
The Evolutionary Significance Of Body Size In Burying Beetles, Ashlee Nichole Momcilovich
The Evolutionary Significance Of Body Size In Burying Beetles, Ashlee Nichole Momcilovich
Theses and Dissertations
Body size is one of the most commonly studied traits of an organism, which is largely due to its direct correlation with fitness, life history strategy, and physiology of the organism. Patterns of body size distribution are also often studied. The distribution of body size within species is looked at for suggestions of differential mating strategies or niche variation among ontogenetic development. Patterns are also examined among species to determine the effects of competition, environmental factors, and phylogenetic inertia. Finally, the distribution of body size across the geographic range of a species or group of closely related is looked at …
Phylogenetics, Biogeography, And Patterns Of Diversification Of Geckosacross The Sunda Shelf With An Emphasis On The Genuscnemaspis (Strauch, 1887), Perry Lee Wood
Theses and Dissertations
In my dissertation I investigate two genera of geckos (Cyrtodactylus and Cnemaspis) that are distributed across Southeast Asia with an emphasis on Cnemaspis. In Chapter 1 I use a multilocus dataset, ancestral area analyses, and molecular clock dating to generate a species level time calibrated phylogeny to test the monophyly of Cyrtodactylus and to identify major biogeographical patterns. I identified that Cyrtodactylus is monophyletic only if the the Sri Lankan genus often recognized as Geckoella is included. The results of the Biogeographical analyses reveal a west to east pattern of diversification. Chapter 2 I use a traditional morphological dataset to …
Phylogenetics, Biogeography, And Patterns Of Diversification Of Geckosacross The Sunda Shelf With An Emphasis On The Genuscnemaspis (Strauch, 1887), Perry Lee Wood
Theses and Dissertations
In my dissertation I investigate two genera of geckos (Cyrtodactylus and Cnemaspis) that are distributed across Southeast Asia with an emphasis on Cnemaspis. In Chapter 1 I use a multilocus dataset, ancestral area analyses, and molecular clock dating to generate a species level time calibrated phylogeny to test the monophyly of Cyrtodactylus and to identify major biogeographical patterns. I identified that Cyrtodactylus is monophyletic only if the the Sri Lankan genus often recognized as Geckoella is included. The results of the Biogeographical analyses reveal a west to east pattern of diversification. Chapter 2 I use a traditional morphological dataset to …
Virulence Of Photorhabdus Spp.: Examining The Roles Of Environment, Evolution, And Genetics In Insect Mortality, Dana Blackburn
Virulence Of Photorhabdus Spp.: Examining The Roles Of Environment, Evolution, And Genetics In Insect Mortality, Dana Blackburn
Theses and Dissertations
Entomopathogenic nematodes (EPNs) (genera Heterorhabditis and Steinernema) kill their invertebrate hosts with the aid of a mutualistic bacterium. The bacteria (Xenorhabdus spp. for steinernematids and Photorhabdus spp. for heterorhabditids) are primarily responsible for killing the host and providing the nematodes with nutrition and defense against secondary invaders. Photorhabdus is a Gram-negative bacterium in the Enterobacteriaceae family with high virulence towards their insect hosts. To achieve high mortality rates Photorhabdus produces a variety of virulence factors such as toxins, lipases, proteases, secretion systems, and fimbriae. EPNs are amenable to laboratory rearing and mass production for biocontrol applications against insects …
Development And Characterization Of Microsatellite Markers For The Grain Amaranths (Amaranthus Spp. L.), Melanie Ann Mallory
Development And Characterization Of Microsatellite Markers For The Grain Amaranths (Amaranthus Spp. L.), Melanie Ann Mallory
Theses and Dissertations
The grain amaranths (Amaranthus hypochondriacus L., A. cruentus L., and A. caudatus L.) are important pseudocereals native to the Americas that have received increased attention for their nutritional content, specifically their balance of amino acids. The objective of this project was to produce and characterize a set of highly informative, reproducible microsatellite markers for the grain amaranths. A total of 1457 clones were sequenced from three genomic libraries enriched for the microsatellite motifs AAC, AAT and AC. Of these, 353 (24%) contained unique microsatellites. An additional 29 microsatellite loci were identified among 728 BAC-end sequences of a newly developed amaranth …
Evolution And Phylogeny Of Basal Winged Insects With Emphasis On Mayflies (Ephemeroptera), Thomas H. Ogden
Evolution And Phylogeny Of Basal Winged Insects With Emphasis On Mayflies (Ephemeroptera), Thomas H. Ogden
Theses and Dissertations
Ephemeroptera (mayflies) is a monophyletic group of semi-aquatic pterygote insects, comprising 3083 species, 376 genera, and 37 described families and are present on all continents, excluding Antarctica, being associated with freshwater and brackish water habitats. The order is unique among pterygote insects in possessing functional wings at the penultimate molt (subimago stage), prior to the full development of genitalia; in all other insects the presence of functional wings occurs only after the final molt. The purpose of this dissertation is to use molecular and morphological data, in order to investigate the position of the order Ephemeroptera among other insect orders, …
Prevalence Of Teleological And Lamarckian Misconceptions Of Natural Selection Among College Students, Bryce T. Battisti
Prevalence Of Teleological And Lamarckian Misconceptions Of Natural Selection Among College Students, Bryce T. Battisti
Theses and Dissertations
Science teachers and researchers note that students must correctly understand the role of natural selection in evolution to make sense of biology. The level of understanding of natural selection can be assessed using the Conceptual Inventory of Natural Selection (CINS) which is a 20-item multiple-choice test that incorporates student misconceptions as distractors. In the present study, Item Response Theory (IRT) was used to analyze the occurance of misconceptions on the CINS among 1192 students in an introductory non-majors biology course. The four most difficult topics in the CINS are: (a) how change occurs in a population; (b) origin of variation; …
Plant Dioecy, Ecology, Evolution And Sex Reversal, D. Carl Freeman
Plant Dioecy, Ecology, Evolution And Sex Reversal, D. Carl Freeman
Theses and Dissertations
The distribution of dioecious species among forty-four plant communities of western United States was examined. The dioecious habit is most prevalent in harsh environments. In many communities, over 20 percent of the species and 40 percent of the individuals are dioecious. Dioecy is most common among woody species which are pollinated by wind. It is concluded that inbreeding depression alone is insufficient to account for all known facts concerning dioecy. Disruptive selection acting upon differential success of gametes produced on sites of differing quality appears to have played a major role in producing separate sexed individuals. Dioecious species reported to …
Evolution Of The Iguanine Lizards (Sauria, Iguanidae) As Determined By Osteological And Myological Characters, David F. Avery
Evolution Of The Iguanine Lizards (Sauria, Iguanidae) As Determined By Osteological And Myological Characters, David F. Avery
Theses and Dissertations
The family Iguanidae is almost completely restricted to the Western Hemisphere with its main radiations occurring in North and South America. There are also representatives on Fiji, Tonga and the Galapagos Islands, in the Pacific Ocean. Distantly related forms are also found on Madagascar off the Southeastern Coast of Africa. Although the iguanid lizards are familiar to most scientists interested in the tropics, their anatomy and evolution is poorly understood.