Biology Commons^™

Diversification And Adaptation In The Andes: Insights From Phylogeography, Malaria, And Hemoglobin Of The House Wren (Troglodytes Aedon), Spencer C. Galen

Biology ETDs

The tropical Andes of South America represent a highly complex landscape characterized by physical barriers to dispersal and stark ecological gradients. The study of intraspecific genetic diversity in widespread Andean species has the potential to elucidate the historical biogeographic events that have driven diversification as well as the processes by which organisms have adapted to their environments in this region. The house wren (Troglodytes aedon) provides a convenient system for the study diversification and adaptation in the Andes, as it is distributed widely across both biogeographic barriers and heterogeneous environments. In chapter one, I utilize house wren and malaria parasite …

Abiotic Drivers Of Chihuahuan Desert Plant Communities, Laura Marie Ladwig

Biology ETDs

Within grasslands, precipitation, fire, nitrogen (N) addition, and extreme temperatures influence community composition and ecosystem function. The differential influences of these abiotic factors on Chihuahuan Desert grassland communities was examined within the Sevilleta National Wildlife Refuge, located in central New Mexico, U.S.A. Although fire is a natural disturbance in many grasslands, fire during drought temporarily increased forb cover and decreased grass cover for several years. The seasonal timing of fire was not important, rather community recovery was more influenced by the persistent drought conditions. N deposition is increasing worldwide due to human activities, and although additional N increases productivity and …

Phylogenetic Revision Of The Genus Arenivaga (Rehn) (Blattodea: Corydiidae), With Descriptions Of New Species, A Key To The Males, And An Investigation Of Its Ecological Niche, Heidi Hopkins

Biology ETDs

The cockroach genus Arenivaga is revised. Forty-eight Arenivaga species are recognized with nine previously known species and 39 described as new including the following: A. pagana sp. n., A. grandiscanyonensis sp. n., A. haringtoni sp. n., A. hopkinsorum sp. n., A. umbratilis sp. n., A. tenax sp. n., A. impensa sp. n., A. trypheros sp. n., A. darwini sp. n., A. nalepae sp. n., A. sequoia sp. n., A. mckittrickae sp. n., A. gaiophanes sp. n., A. belli sp. n., A. estelleae sp. n., A. delicata sp. n., A. mortisvallisensis sp. n., A. milleri sp. n., A. pratchetti sp. n., …

Analysis Of Genes Required For Quiescent Cell Formation In Stationary Phase Cultures Of Saccharomyces Cerevisiae, Melissa R. Wilson

Biology ETDs

Yeast cells in stationary phase cultures, after several days growth in rich, glucose-based medium (YPD), are separable by density-gradient centrifugation into two fractions. The heavier, quiescent cells are mostly virgin daughters whereas the less-dense, non-quiescent cells, are a typical mixture of daughters to aged cells. Quiescent cells can also be separated based on expression of specific GFP-tagged proteins, including many that are localized to the mitochodria. To ask the question, what genes are required for this differentiation process, we used a combination of the diploid, homozygous yeast deletion set, the heterozygous deletion set (carrying one deleted 'essential' gene) and a …

The Effects Of Precipitation Manipulation On Carbohydrate Dynamics And Mortality In A Piñon-Juniper Woodland, Lee Turin Dickman

Biology ETDs

Drought-induced forest mortality is an increasing global problem with far-reaching consequences, yet mortality mechanisms remain poorly understood. Depletion of non-structural carbohydrate (NSC) stores has been implicated as a major factor in drought-induced mortality, but experimental field tests are rare. We conducted an ecosystem-scale precipitation manipulation experiment and evaluated leaf and twig NSC dynamics of two co-occurring conifers with different water regulation strategies; the relatively drought-averse piñon pine (Pinus edulis) and relatively drought-tolerant oneseed juniper (Juniperus monosperma). Experimental drought caused decreased leaf starch in dying trees of both species and increased allocation to glucose and fructose in juniper, consistent with osmoregulation …

Molecular Characterization Of The Freshwater Snail Physella Acuta, Journey R. Nolan

Biology ETDs

Current insights into general animal biology, including immune function, are derived mostly from a few model organisms, a necessity imposed by effort required for in-depth studies. Modern next-generation sequencing (NGS) enables genomics-level investigations to test whether specific aspects of biology are general or unique across animal phylogeny. Meaningful comparisons require thorough identification of phylogenetically-relevant species. To provide a touchstone for Biomphalaria glabrata, a freshwater snail that is a major study model for invertebrate immunity, physid snails (Physidae; Hygrophila; Panpulmonata; Gastropoda; Mollusca) will be developed as a model for comparative immunogenomics. Chapter 1 introduces current research capabilities and details the rationale …

Systematics Within The Zopheridae Complex (Coleoptera: Tenebrionoidea), Nathan Patrick Lord

Biology ETDs

The Ironclad Beetles, Cylindrical Bark Beetles, and Monommatid Beetles are a cosmopolitan family with over 1,700 species worldwide. Now constituting members from three previous families (Zopheridae, Monommatidae, Colydiidae), Zopheridae represent a wide array of morphological diversity and variability. Larvae of most members are fungivores/detritovores, while some are suspected of boring into sound wood. Adults are predaceous or fungivores, and some zopherids have been linked to the spread of fungal disease. Morphologically, adults are hard to separate from other tenebrionoid families. Zopherids can be distinguished by 9-11 segmented antennae with a usually abrupt, 1-3 segmented club, antennal insertions concealed from above, …

Disentangling Historical Biogeography And Anthropogenic Introductions: A Case Study Of Red Shiner (Cyprinella Lutrensis), Tracy A. Diver

Biology ETDs

Aim: Determine evolutionary events that have shaped observed patterns of diversity in Red Shiner within the Rio Grande Basin, New Mexico. Location: Pecos, Delaware, Rio Grande and Canadian Rivers, New Mexico, United States. Methods: We used DNA sequence data from two mitochondrial genes (cytochrome b and ND4), nuclear RAG-1 intron, and geometric-morphometric and meristic data to test alternative hypothesis regarding the evolutionary history of native populations of Red Shiner in New Mexico. Results: MtDNA gene trees revealed deeply divergent lineages (Great Plains and Coastal) with in situ diversification within each geographic lineage between the Rio Grande and Pecos River. Nuclear …

Scaling Of Crop Diversity And Optimal Allocation Of Foodshed Infrastructure, Michael Chang

Biology ETDs

Food hubs are organizations that manage the aggregation and distribution of local products, and are a small, but growing means to satisfy high demand for diverse, healthy diets. However, economic barriers inhibit small producers and distributors from developing mainstream, local consumer alternatives to industrial-scale products. To build foodshed, distribution hubs could help overcome these challenges by reducing costs through shared refrigeration, processing, and transportation infrastructure. However, there is no theory to help plan them. I present and test theory to allocate foodshed infrastructure based on insight by Dunn, et al. (2011) that Shannon diversity measured relative to a whole set …

Sympatric Speciation Is Reinforced By Predation, Parasite Load, Reproductive Character Displacement, And Sexual Selection In Two Species Flocks Of Pupfish (Cyprinodon Spp), Rhiannon J. D. West

Biology ETDs

Sympatric speciation, the divergence of one lineage into two or more lineages within one geographic range, is often driven by disruptive selection on niche utilization. While niche specialization is found in sympatrically speciated groups, it is often reinforced by other strong selective pressure. This dissertation examines the role of predation, morphology, mate choice, and parasite load in maintaining reproductive isolation in two sympatrically speciated species flocks of pupfish (Cyprinodon). The role that predation, morphology and male and female mate choice play in reproductive isolation is examined in the Bahamian species flock. To examine the role of predation, we focus on …

The Effects Of Climate Change On Stream Invertebrates In Their Role As Biological Indicators And Responders To Disturbance, Anna T. Hamilton

Biology ETDs

Global climate models provide estimates of future changes in air temperature and precipitation patterns, drought, flooding, sea-level rise, and increases in the frequency, duration, and intensity of extreme heat and storm events. These climate changes will affect stream invertebrate communities directly, indirectly, and through interactions with other stressors, resulting in a range of biological responses, including species range shifts, losses and replacements, novel community compositions, and altered ecosystem functions and services. Effects will vary regionally and present heretofore unaccounted influences on biomonitoring, which water-quality agencies use to assess the status and health of ecosystems as required by the Clean Water …

Mhc And Mate Choice In Anolis Sagrei, Angela S. Hung

Biology ETDs

The study of sexual selection saw its intrepid inception when Charles Darwin observed the earnest with which many male birds must court a female before she will, but often not, mate with him. His idea of the choosy female' was a radical one in the Victorian era when women were regarded as the 'passive sex. In the century and a half that followed, sexual selection driven by female choice is now widely accepted and strongly supported. Today, with emerging technologies, the nuances and complexities of sexual reproductive are finally coming to light. Female choice in two species is described here. …

Life History And Morphometric Variation Of Gambusia Nobilis At Bitter Lake National Wildlife Refuge, Alyssa Renee Hopkins

Biology ETDs

The Pecos Gambusia, Gambusia nobilis, is an endangered, live bearing fish inhabiting sinkholes in a restricted range of the Pecos River Watershed in New Mexico and Texas. The sink holes at Bitter Lake National Wildlife Refuge (BLNWR), Roswell, NM create isolated habitats with varying ecological conditions (habitat size, community composition, dissolved oxygen, salinity and pH). This ecological variation imposes unique selective pressures that may shape differences in life history characteristics and morphology between populations. The goals of this research were to characterize seasonal and population variation in 1) life history characteristics, 2) embryo development patterns, 3) morphology and 4) explore …

A Holarctic Perspective On Mammalian Evolution: The Evolutionary And Biogeographic History Of Red-Backed Voles And Their Close Relatives (Rodentia: Arvicolinae), Brooks A. Kohli

Biology ETDs

The influence of Quaternary environmental changes on demography and geographic distribution is paramount to understanding how contemporary genetic diversity is partitioned in high-latitude species. This history of change in northern ecosystems sets the stage for forecasting how species inhabiting tundra and boreal forest will respond to the ongoing shift in climate. Utilizing broad geographic and taxonomic sampling, a multilocus species tree approach, ecological niche models, and population genetic techniques, I investigate the evolutionary and biogeographic history of a Holarctic mammal, the northern red-backed vole (Clethrionomys rutilus) and the systematics of the tribe it belongs to, Clethrionomyini. This tribe of forest …

Mitochondrial Genome Evolution In Pupillid Land Snails, Jason D. Marquardt

Biology ETDs

Pupillid land snails (Family Pupillidae) are small (< 6mm) snails with a broad geographic distribution and often found in very high density in their habitat. The sequencing of the mitochondrial genome (mt genome) of three pupillid taxa has been undertaken to understand their genome evolution more fully. The Gastrocopta cristata mitochondrial genome is 14,060 bp in length and contains 13 protein coding genes, 2 rRNA genes and 22 tRNA genes. The Pupilla muscorum, and Vertigo pusilla genomes contain all of the same genes but are of differing total sizes, 14,149 bp and 14,078 bp respectively. The AT content of the three genomes is similar at ~71% A+T which is comparable to their closest sequenced relatives. There are no major gene rearrangements among the mt genomes of the three pupillids, but the positions of many tRNA genes differ from those of Albinaria caerulea. There is a genomic sequence region of high concentration of thymine on the leading strand of the mt genome that is shared among all three genomes as well as their relatives.

Habitat Preference Of Western Diamond-Backed Rattlesnakes (Crotalus Atrox) At Bosque Del Apache National Wildlife Refuge, New Mexico: An Analysis At Multiple Scales, Theresa Lorraine Mcinnes

Biology ETDs

Bosque del Apache National Wildlife Refuge is located in central New Mexico in the Chihuahuan desert. Approximately 25% of the refuge spans the Rio Grande floodplain and consists of managed riparian and agriculture areas. The upland areas are dominated by creosote bush (Larrea tridentata), honey mesquite (Prosopis sp.), and four-wing saltbush (Atriplex canescens). Western diamond-backed rattlesnakes (Crotalus atrox) are habitat generalists of dry lowland areas and commonly use dry washes, Larrea and Prosopis desert, rocky slopes, scrub/grassland, man-made structures, and less commonly hydric habitats. A high diversity of vegetation types span the refuge and hydric and upland habitats are often …

Systematics Of Longhorned Beetles (Insecta: Coleoptera: Cerambycidae), Eugenio Hernán Nearns

Biology ETDs

The longhorned wood boring beetles (Insecta: Coleoptera: Cerambycidae) are a diverse and economically important group of insects. With an estimated 4,000 genera and more than 35,000 described species, the Cerambycidae comprise one of the largest beetle families. Cerambycid beetles are found on all continents except Antarctica, from sea level to montane sites as high as 4000 m. Cerambycids are among the most serious wood boring pest species globally, affecting many agricultural crops, ornamental trees, and lumber products, causing millions of dollars in damage each year. Despite their economic importance and biological diversity, relatively little is known of cerambycid beetle ecology, …

Exploring Signals Of Historical Demography In Boreal Mammals Through Integration Of Statistical Conservation Phylogenetics, Taxonomy, And Comparative Phylogeography, Jason L. Malaney

Biology ETDs

Understanding how diversity is partitioned across the landscape can provide perspectives related to the environmental processes that have influenced the evolutionary history of organisms. This main idea, often termed phylogeography, serves as the backdrop to my research where I explore three broad concepts including historical biogeography, cryptic diversity and ecology, and conservation phylogenetics. I address various questions in each of these concepts by using a set of mammals that are associated with montane and mesic environments of North America. More specifically, I focus on the jumping mice (Zapodidae) to test hypotheses that scale to the broader community. This approach allows …

Molecular Control Of Muscle Patterning, Development And Stability In Drosophila, Elisa Mignon Labeau Dimenna

Biology ETDs

Muscle is a highly conserved and specialized tissue in animals. Failure of proper muscle patterning, maintenance and stability in animals can have variety of consequences for the individual. Mutations in loci that control muscle can result in death during embyogenesis, dysmorphism, and/or reduced lifespan after progressive muscle degeneration (Emery 2002, Mathews and Moore 2003, Amato and Griggs 2011). Muscle defects, such as these, have origins ranging from improper transcriptional control to direct sequence disruptions in proteins that play a wide variety of roles in the cell (Emery 2002, Mathews and Moore 2003, Amato and Griggs 2011). Thus, out of this …

Regulation Of Hydraulic Function And Consequences For Drought-Related Mortality In Mature Woody Plants, Jennifer A. Plaut

Biology ETDs

Precipitation and temperature patterns are expected to shift over at least the next century due to anthropogenic climate change. Effects of these shifts may be felt most acutely in arid and semi-arid regions where water is already the most limiting resource. Vegetation mortality due to drought is a likely outcome of predicted future climate, with consequences for ecosystem structure and function and feedbacks on regional and global climate. Yet, mechanisms and interactions of key plant drought responses and the end-point of mortality remain poorly understood. In this dissertation I examine the roles of xylem cavitation resistance and stomatal control of …

Energy Development And Conservation Of Sympatric Wildlife: New Approaches To Meet Growing Challenges, William Christian Dunn

Biology ETDs

Conflicts between energy development and conservation of sympatric wildlife are becoming more acute as demand for energy increases. Resolving these conflicts is complex-- solutions must address the role of location, scale, and connectivity in persistence of populations. In Chapter 1, I use the MaxEnt species distribution model and pertinent climate variables to predict the natural distribution of the Lesser Prairie Chicken (LPC) (Tympanuchus pallidicinctus), a prairie grouse adversely affected by habitat loss from energy development. Within the geographic range of LPC, precipitation was strongly associated with its distribution in the north, whereas temperature was strongly associated with its distribution in …

Effects Of Climate Change Upon Birds In The Mojave And Sonoran Deserts, Harinamsimran Kaur Khalsa

Biology ETDs

Climate change has increasingly become an area of concern in relation to ecological communities. In this study, climatic signals were investigated to determine whether bird diversity indices in the Breeding Conservation Region (BCR) of the Mojave and Sonoran Deserts were related (1) to the oceanic/atmospheric systems El Nino Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO), and/or the Atlantic Multidecadal Oscillation (AMO); (2) to regional moisture influences determined by the Palmer Drought Severity Index (PDSI); and (3) to local precipitation and temperature. Specifically, an examination was conducted to determine the relationship between climatic variables for thirteen bird species, total abundance …

Genetic Diversity, Local Differentiation, And Adaptive Evolution In Introduced Populations Of The Invasive Plant Isatis Tinctoria L. (Brassicaceae), Heather L. Simpson

Biology ETDs

Populations of invasive species are often characterized as genetically depauperate, an inherent consequence of the colonization process. It has also been suggested that species that are able to avoid these reductions in genetic diversity may be better able to adapt to their introduced range. Evolutionary change can play an important role in the invasion process if novel selective pressures drive adaptive evolution. Species that are able to avoid reductions in genetic diversity associated with colonization may be better able to adapt to their introduced range. To better understand the genetic processes following invasion, introduced populations of the invasive mustard, Isatis …

Pollination Ecology Of Agave Palmeri In New Mexico, And Landscape Use Of Leptonycteris Nivalis In Relation To Agaves, Angela E. England

Biology ETDs

Where animals spend time can provide important clues to their ecological needs, but this information is very difficult to obtain for small volant animals. The research described in Chapter 1 was an attempt to discern how L. nivalis utilize the landscape in relation to the distribution of Agave havardiana in Big Bend National Park, Texas. I found that although the landscape use of Leptonycteris nivalis is centered on habitat with high concentrations of blooming A.havardiana, it is not restricted to those areas, and furthermore adults and juveniles may differ in their behavior. Adult females may remain near food sources in …

The Effect Of Increased Growth Temperature On Mid-Day And Mid-Night Co2 Fluxes In Populus Deltoids, Rachel Zulick

Biology ETDs

As global temperatures rise, understanding the effects of increased temperature on daily carbon dioxide fluxes is necessary to predict changes to the global carbon cycle. Using tunable diode laser spectroscopy, I measured CO2 fluxes and changes in isotopic composition of root respiration, leaf respiration and photosynthesis over a 12-hour night to day transition. I found that after a 10°C increase in growth temperature for four weeks, root CO2 fluxes acclimated to the higher temperature (i.e. they were not significantly different from controls). In contrast, both photosynthesis and respiration of leaves were higher at the elevated growth temperature. Though the root …

Historical And Topographic Drivers Of Tropical Insular Diversity: Comparative Phylogeography Of Eleutherodactylus Antillensis And E. Portoricensis, Two Ecologically Distinctive Frogs Of The Puerto Rican Bank, Brittany Suzanne Barker

Biology ETDs

Topographically complex islands present opportunities for in situ (within-island) allopatric speciation because of increased chances for isolation in separate mountain ranges, as well as greater opportunity for fragmentation by high sea levels and climate-driven changes in habitat distribution. Climatic oscillations of the Quaternary (Pleistocene - Holocene; ~2.5 million years ago to the present) may have influenced the severity of vicariant barriers among and within islands, yet how these events influenced evolution of tropical insular biota is not well understood. This dissertation explores the role of topographic complexity and climate-driven range shifts resulting from sea-level changes and habitat suitability in shaping …

Pattern And Process In Metabolic Ecology: From Biotic Interactions To Cultural Diversity Gradients, William R. Burnside

Biology ETDs

Many ecological patterns and processes are functions of metabolism (Brown 2004), meaning the acquisition, transformation, and allocation of energy, materials, and information within the bodies of individuals and among members of human and other animal societies. Individual metabolic rate should influence behavior by determining the energy available for action as well as the rate at which the body requires fuel. First, I test a key prediction of the metabolic theory of ecology (MTE), that biotic interaction rates are characteristic functions of temperature. Findings support this prediction and suggest that herbivory, predation, parasitism, parasitoidy, and competition increase exponentially with temperature and …

Diversification In Andean Tit-Tyrants (Aves, Tyrannidae), Shane G. Dubay

Biology ETDs

In my thesis I investigate evolution and diversification of montane birds that inhabit dramatic environmental and latitudinal gradients, specifically within the genus Anairetes (Aves, Tyrannidae). I use phylogenetic, population genetic, and physiological methods to examine patterns of diversification across environmental gradients. In the first chapter, I infer the phylogeny of Anairetes tit-tyrants to provide an essential phylogenetic framework to ask subsequent questions of biogeography and diversification within the group. In the second chapter, I investigated the role of differential adaptation to altitude in promoting diversification and maintaining species limits between A. reguloides and A. nigrocristatus. The phylogeny of the flycatcher …

The Contribution Of Young-Of-Year Fishes To Aquatic Food Web Dynamics In An Arid-Land River System (Rio Grande, New Mexico), Corey Anne Krabbenhoft

Biology ETDs

1. Larval fishes have a rich history in ichthyological research. However, relatively little attention has been given to the role of young-of-year (YOY) fishes in ecosystem processes. Despite difficulties of sampling and identifying these small fishes, YOY may serve an important role in the dynamics of some aquatic communities. The specific role of YOY fishes in aquatic, desert food webs remains largely uncharacterized.

2. We hypothesize that YOY fishes may control abundance and community composition of lower trophic levels (i.e., aquatic invertebrates) because they are numerically dominant predators during the growing season. The goal of this study is to determine …

Effects Of Global Change On Savanna Grassland Ecosystems, Sally Elizabeth Koerner

Biology ETDs

Humans are altering the environment locally and globally through climate and land use change. Global temperature is increasing, precipitation patterns are becoming more variable, disturbance regimes are being altered, and ecosystems are being simplified as multi-species communities are replaced by monocultures of crops or livestock. Grasslands, which cover approximately a third of the terrestrial lands, are ecologically and economically significant, thus their responses to environmental change will have dramatic consequences for global patterns of productivity, biodiversity, and food production. This dissertation research investigates how the three main drivers of mesic grassland ecosystems — precipitation, grazing, and fire - interact to …