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University of Nebraska - Lincoln
School of Biological Sciences: Dissertations, Theses, and Student Research
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- Behavioral plasticity (3)
- Evolution (2)
- Green swordtails (2)
- Predation (2)
- Sexual selection (2)
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- Alternative mating tactics (1)
- Bacillus cereus (1)
- Blood-oxygen Affinity (1)
- DNA repair (1)
- Dolomedes tenebrosus (1)
- Drosophila (1)
- Drosophila melanogaster (1)
- Ecological risks of transgenic crops (1)
- Ecology (1)
- Energy storage (1)
- Female choice (1)
- Female-female (1)
- Fitness benefits (1)
- Foraging (1)
- Genetics (1)
- Green swordtail (1)
- Gryllus lineaticeps (1)
- Hematocrit (1)
- Hemoglobin (1)
- Host specificity (1)
- Hybridization (1)
- Hypoxia (1)
- Life cycle (1)
- Mammal (1)
- Mate choice (1)
Articles 1 - 15 of 15
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A Tale Of Two Genomes: The Complex Interplay Between The Mitochondrial And The Nuclear Genomes, Abhilesh S. Dhawanjewar
A Tale Of Two Genomes: The Complex Interplay Between The Mitochondrial And The Nuclear Genomes, Abhilesh S. Dhawanjewar
School of Biological Sciences: Dissertations, Theses, and Student Research
Mitochondria, the product of an ancient endosymbiotic event are pivotal to eukaryotic cells by synthesizing the majority of the cell’s ATP output. However, modern- day mitochondria are completely dependent on more than one thousand nuclear-encoded products for their function and the maintenance of their genomes. The fundamentally different ways in which the mitochondrial (mtDNA) and the nuclear (nucDNA) genomes are replicated and inherited lead to captivating coevolutionary dynamics between them. The aims of this dissertation are to investigate the coevolutionary dynamics between the mitochondrial and nuclear genomes at three distinct biological scales. At the organismal level, we use a Drosophila …
Plant Mitochondrial Genome Evolution And Structure Has Been Shaped By Double-Strand Break Repair And Recombination, Emily Wynn
School of Biological Sciences: Dissertations, Theses, and Student Research
Plant mitochondrial genomes are large but contain a small number of genes. These genes have very low mutation rates, but genomes rearrange and expand at significant rates. We propose that much of the apparent complexity of plant mitochondrial genomes can be explained by the interactions of double-strand break repair, recombination, and selection. One possible explanation for the disparity between the low mutation rates of genes and the high divergence of non-genes is that synonymous mutations in genes are not truly neutral. In some species, rps14 has been duplicated in the nucleus, allowing the mitochondrial copy to become a pseudogene. By …
Behavioral Plasticity Across Non-Social Contexts In Female Green Swordtails, Xiphophorus Hellerii, Lindsey M. Coit
Behavioral Plasticity Across Non-Social Contexts In Female Green Swordtails, Xiphophorus Hellerii, Lindsey M. Coit
School of Biological Sciences: Dissertations, Theses, and Student Research
Phenotypic plasticity is the ability of an individual to alter its phenotype in response to environmental change. Individuals that express plasticity in behavior can quickly respond to changes that occur in the environment. Therefore, individuals that exhibit behavioral plasticity can alter their behavioral expression to best match current environmental conditions. The degree and direction of behavioral plasticity may be influenced by variation in individual characteristics. Understanding how variation in individual traits affects behavioral plasticity, and, whether patterns of behavioral plasticity are consistent across behavioral contexts are important topics to explore as we try to better understand how plasticity evolves and …
Inter- And Intra-Individual Variation In Predator-Related Behavioral Plasticity Expressed By Female Green Swordtails (Xiphophorus Hellerii), Rachael A. Disciullo
Inter- And Intra-Individual Variation In Predator-Related Behavioral Plasticity Expressed By Female Green Swordtails (Xiphophorus Hellerii), Rachael A. Disciullo
School of Biological Sciences: Dissertations, Theses, and Student Research
Phenotypic plasticity is the ability of one genotype to express multiple phenotypes under variable environments. Behavioral plasticity is a type of phenotypic plasticity in which individuals adjust behavior in response to changes in environment. Often, behavioral plasticity is studied at the level of the population, rather than at the level of the individual. Further, few studies have considered the effect of individual traits, such as size and age, on the expression of behavioral plasticity, or, how individual plasticity may be correlated across different contexts. In this study, we used female green swordtails (Xiphophorus hellerii) to test the effects …
Proximate And Evolutionary Causes Of Sexual Size Dimorphism In The Crab Spider Mecaphesa Celer, Marie Claire Chelini
Proximate And Evolutionary Causes Of Sexual Size Dimorphism In The Crab Spider Mecaphesa Celer, Marie Claire Chelini
School of Biological Sciences: Dissertations, Theses, and Student Research
Animal species’ body sizes result from the balance between selection for survival and selection for reproduction. In species with sexual size dimorphism (SSD), this balance differs between females and males, resulting in distinct sizes despite similar constraints. I used an integrative approach to understand how sexual section, and differences in developmental trajectories and metabolic physiology, resulted in the female biased SSD of the crab spider Mecaphesa celer (Thomisidae). SSD in spiders is often assumed to be a consequence of selection for early male maturation, which should provide males with additional mating opportunities. My results allow us to discard mate …
Stress Responses And Energy Storage In Drosophila Melanogaster Selected For Resistance To A Gram-Positive Bacillus Cereus Spores, Zhen Hu
School of Biological Sciences: Dissertations, Theses, and Student Research
A survival response study was carried out by using D. melanogaster and the opportunistic pathogen B. cereus as the agent of selection. The spores of B. cereus, a gram-positive bacteria that can cause the human pathogen disease, were applied in our artificial laboratory selection. Selected lines were treated with B. cereus spores. Wound control lines were punctured with a needle dipped into sterile H2O. Control lines did not apply any treatment. Three different environmental treatments were used within each line type (autoclaved spores of B.cereus, sterile H2O and no treatment). The autoclaved spores were …
The Roles Of Phenotypic Plasticity And Genotypic Specialization In High Altitude Adaptation, Danielle M. Tufts
The Roles Of Phenotypic Plasticity And Genotypic Specialization In High Altitude Adaptation, Danielle M. Tufts
School of Biological Sciences: Dissertations, Theses, and Student Research
In vertebrates living at high altitude, arterial hypoxemia may be ameliorated by reversible changes in the oxygen-carrying capacity of the blood (regulated by erythropoiesis) and/or changes in blood–oxygen affinity (regulated by allosteric effectors of hemoglobin function). These hematological traits often differ between taxa that are native to different elevational zones, but it is often unknown whether the observed physiological differences reflect fixed, genetically based differences or environmentally induced acclimatization responses (phenotypic plasticity). Here, we report measurements of hematological traits related to blood–O2 transport in populations of deer mice (Peromyscus maniculatus) that are native to high- and low-altitude …
The Origin And Molecular Evolution Of Two Multigene Families: G-Protein Coupled Receptors And Glycoside Hydrolase Families, Seong-Il Eyun
The Origin And Molecular Evolution Of Two Multigene Families: G-Protein Coupled Receptors And Glycoside Hydrolase Families, Seong-Il Eyun
School of Biological Sciences: Dissertations, Theses, and Student Research
Multigene family is a group of genes that arose from a common ancestor by gene duplication. Gene duplications are a major driving force of new function acquisition. Multigene family thus has a fundamental role in adaptation. To elucidate their molecular evolutionary mechanisms, I chose two multigene families: chemosensory receptors and glycoside hydrolases. I have identified complete repertoires of trace amine-associated receptors (TAARs), a member of chemosensory receptors, from 38 metazoan genomes. An ancestral-type TAAR emerged before the divergence between gnathostomes (jawed vertebrates) and sea lamprey (jawless fish). Primary amine detecting TAARs (TAAR1-4) are found to be older and have evolved …
Predation And Behavioral Plasticity In Green Swordtails: Mate Choice In Females And Exploratory Behavior In Males, Andrew J. Melie
Predation And Behavioral Plasticity In Green Swordtails: Mate Choice In Females And Exploratory Behavior In Males, Andrew J. Melie
School of Biological Sciences: Dissertations, Theses, and Student Research
Two studies were carried out with green swordtails, Xiphophorus helleri, to investigate the effect of predation on swordtail behavior, and to determine how behavioral plasticity operates in both a mate choice and an anti-predator context. Male green swordtails vary in colorful conspicuous traits, e.g. the colorful dorsal fin and sword. Female swordtails have a preexisting bias for males with a sword, and prefer long-sworded males to short-sworded males, but this preference is plastic. The first study examined predator-related plasticity in the behavior of males differing in size. Smaller males showed greater behavioral plasticity; they were more active in the absence …
Spontaneous Male Death And Monogyny In The Dark Fishing Spider Dolomedes Tenebrosus Hentz, 1843 (Araneae, Pisauridae), Steven K. Schwartz
Spontaneous Male Death And Monogyny In The Dark Fishing Spider Dolomedes Tenebrosus Hentz, 1843 (Araneae, Pisauridae), Steven K. Schwartz
School of Biological Sciences: Dissertations, Theses, and Student Research
Male animals typically attempt to mate with multiple females in order to increase their reproductive success. In some species, however, males instead invest in fertilizing the eggs of a single female. Monogyny (male monogamy) is found in a diverse assemblage of taxa, and recent theoretical work reveals that a male-biased sex ratio can favor the evolution of this relatively rare mating system. We integrate this theoretical framework with field observations and laboratory experiments involving the sexually size dimorphic fishing spider, Dolomedes tenebrosus. Results from mating trials revealed a novel form of self-sacrifice behavior where males spontaneously die when they …
Gene Duplication And The Evolution Of Hemoglobin Isoform Differentiation In Birds, Michael T. Grispo
Gene Duplication And The Evolution Of Hemoglobin Isoform Differentiation In Birds, Michael T. Grispo
School of Biological Sciences: Dissertations, Theses, and Student Research
The majority of bird species co-express two functionally distinct hemoglobin (Hb) isoforms in definitive erythrocytes: HbA (the major adult Hb isoform, with α-chain subunits encoded by the αA-globin gene) and HbD (the minor adult Hb isoform, with α-chain subunits encoded by the αD-globin gene). The αD-globin gene originated via tandem duplication of an embryonic α-like globin gene in the stem lineage of tetrapod vertebrates, which suggests the possibility that functional differentiation between the HbA and HbD isoforms may be attributable to a retained ancestral character state in HbD that harkens back to a primordial, …
Life History Tradeoffs And Phenotypic Plasticity: The Tale Of A Flight Polyphenic Field Cricket, Chandreyee Mitra
Life History Tradeoffs And Phenotypic Plasticity: The Tale Of A Flight Polyphenic Field Cricket, Chandreyee Mitra
School of Biological Sciences: Dissertations, Theses, and Student Research
Most organisms are resource limited. Such limitations can result in tradeoffs between life history traits -- any traits that affect survival or reproduction. Flight polyphenic field crickets are thought to be a classic example of such a life history tradeoff, in which individuals tradeoff investment in flight capability and investment in reproduction. This polyphenism results from the interaction of two morphological traits: wing morphology (short or long) and flight muscle morphology (functional pink or non-functional white), and is affected by both genes and the environment. I examined life history traits of a flight polyphenic field cricket, Gryllus lineaticeps. First, …
Multilocus And Parametric Analyses Of The Evolutionary History Of The Amazonian Peacock Cichlids, The Genus Cichla (Teleostei: Cichlidae), Stuart Willis
School of Biological Sciences: Dissertations, Theses, and Student Research
Accurate knowledge of species boundaries and species phylogeny are fundamental to testing hypotheses of recent evolutionary processes, but the estimation of these partitions is challenging due both to inherent confusion about what is being estimated as well as the data available to estimate them. Using multilocus data from mtDNA, microsatellites, and nuclear locus sequences of over 1100 individuals, we delimited eight separately evolving species of Cichla rather than the 15 described. Among species we found evidence of rare but widespread introgressive hybridization, while within these species we observed evidence of long-term gene exchange and constrained evolutionary trajectories. In most cases …
Ecological Effects Of Virus-Resistant Transgenic Squash, Holly R. Prendeville
Ecological Effects Of Virus-Resistant Transgenic Squash, Holly R. Prendeville
School of Biological Sciences: Dissertations, Theses, and Student Research
Two ecological risks associated with the use of transgenic crops include the effects of transgene products on non-target organisms and the effects of a transgene after it moves from crops into a wild plant population. In work presented here, we specifically investigate the ecological risks of virus-resistant transgenic squash. We observed pollinator behavior to determine if pollinators are affected by nontarget effects of the virus-resistant transgene. We found that pollinator behavior did differ between conventional and virus-resistant transgenic squash due to pleiotropic effects of the transgene. This difference in pollinator behavior can affect plant mating patterns, thereby affecting crop-wild hybridization …
Ecology And Relationships Of Rhabdias Spp. (Nematoda: Rhabdiasidae) From North American Amphibians And Reptiles, Gabriel J. Langford
Ecology And Relationships Of Rhabdias Spp. (Nematoda: Rhabdiasidae) From North American Amphibians And Reptiles, Gabriel J. Langford
School of Biological Sciences: Dissertations, Theses, and Student Research
Lungworms of the cosmopolitan genus Rhabdias (Nematoda: Rhabdiasidae) are among the most common parasites of amphibians and squamate reptiles. The life cycles, life histories, host specificities, and evolutionary relationships of Rhabdias spp. were studied through examination of their free-living and parasitic stages in amphibians and reptiles. This study found free-living development of anuran lungworms was primarily limited to heterogonic reproduction, whereas snake lungworms primarily reproduced homogonically. Infective anuran lungworms penetrated the skin of frogs and toads; in contrast, snake lungworms penetrated snake esophageal tissue during per os infections. Our molecular phylogeny strongly supported separate clades for anuran and snake lungworms, …