Ecology and Evolutionary Biology Commons^™

Screening H3 Histone Acetylation In A Wild Bird, The House Sparrow (Passer Domesticus), Daniella Ray

Electronic Theses and Dissertations

Epigenetic mechanisms are increasingly understood to have major impacts across ecology. However, one molecular epigenetic mechanism, DNA methylation, currently dominates the literature. A second mechanism, histone modification, is likely important to ecologically relevant phenotypes and thus warrants investigation, especially because molecular interplay between methylation and histone acetylation can strongly affect gene expression. There are a limited number of histone acetylation studies on non-model organisms, yet those that exist show that it can impact gene expression and phenotypic plasticity. Wild birds provide an excellent system to investigate histone acetylation, as free-living individuals must rapidly adjust to environmental change. Here, we screen …

Impacts Of Algal Morphology And Water Flow On Macroalgal Microplastic Capture, Cheyenne M. Adams

Honors College Theses

Microplastic pollution is a major area of concern in marine environments, especially as microplastics enter the food web. This study used pipe cleaners and two lichen species as algal mimics, and Chaetomorpha sp. and Chondrus crispus as model algal species to test the effects of morphology and biomass on microbead and foam capture. This study also utilized two different water flow methods: vortices and waves. Results suggest that water flow, as well as biomass and morphology, play a role in microplastic capture in macroalgae. For all mimics and algal species, except Cladonia lichens, turfs with increased biomass and length showed …

Influence Of Plant Density On Rainfall Interception By Spartina Alterniflora, Hannah K. Longaberger

Honors College Theses

Abstract

Spartina alterniflora is an abundant plant in eastern US and Gulf coast salt marshes; it is important in maintaining a diverse ecosystem. Salt marshes are impacted by rainstorms, which may affect erosion events. This project examined the partitioning of rainfall on single plants of various sizes and on central plants within different canopy densities of S. alterniflora. By calculating the rain stemflow (SF), throughfall (TF), and water adhered to the stem in S. alterniflora, we gained insight to rainfall partitioning with different plant features. My research found no statistically significant relationship between different plant features and SF, TF, …

Effects Of Water Quality On Oyster Health On Georgia Coast, Laurel Henderson

Honors College Theses

ABSTRACT

Oysters are an economically and ecologically important shellfish species found along most coastlines. Along the Georgia coastline, oysters form extensive reefs, and are economically important as a food source. In addition, oysters perform a vital role in maintaining water quality due to their high filtration capacity in coastal waters. Oyster reefs form solid, 3-D substrate that prevent coastline erosion and provide structure for numerous other coastal species to grow, including many commercially and recreationally important species. Water quality factors, such as temperature and salinity, can influence oyster density, condition, and growth, and ultimately affect the services the reefs provide …

The Potential Role Of Phenotypic Plasticity In The Ability Of Hydrocotyle Bonariensis To Occupy Two Different Habitats, Harold Ralph Parsons Iii

Honors College Theses

Phenotypic plasticity is the ability of an organism to change morphology and/or physiology in response to changes in the environment. Hydrocotyle bonariensis is a coastal perennial herb found in both coastal sand dunes and inland coastal plain habitats in Georgia. The purpose of this study was to determine if there were differences in leaf morphology for populations of H. bonariensis in coastal sand dune and inland coastal plain habitats. Leaf morphology and microenvironmental variables were compared between H. bonariensis populations at Tybee Island (TI), GA, representing the coastal sand dune habitat, and Georgia Southern University Armstrong Campus (GSU) in Savannah, …

Dna Methylation Among Chestnut-Crowned Babblers, Caddie E. Nguyen

Honors College Theses

Many Australian birds, including chestnut-crowned babblers, commonly use cooperative breeding. In these species, individuals may delay or refuse dispersal to provide care to the offspring of the others instead of producing their own. This system challenges natural selection evolution and postulates that reproductively advantage genes will be more favorable. One possibility that contributes to chestnut-crowned babblers’ dispersal behavior is the epigenetic modifications interacting between the genome and the environment during development. Chestnut-crowned babblers (Pomatostomus ruficeps) are usually found in arid and semi-arid zones, which are varied and poor-conditioned. In the undesired conditions, helpers are needed for breeding to occur …

Sex And Starvation Influences Latrotoxin Expression In The Brown Widow Spider, Mattie Harris

Honors College Theses

Widow spiders (genus Latrodectus) are well-known for their potent venom. Seven latrotoxin proteins constitute the main components of widow spider venom. The vertebrate specific (α-latrotoxin) and insect specific (α-latroinsectotoxin) latrotoxins have been well-characterized with respect to structure and function. Regulation of latrotoxin gene expression is not well understood but sex and feeding could be factors influencing production. In this study, I used quantitative qPCR to (1) characterize the expression patterns of both the insect and vertebrate specific latrotoxins in male and female brown widow spiders (Latrodectus geometricus) to characterize sex-biased expression and to (2) study expression patterns …

Stop, Then Go! Rapid Acceleration Offsets The Costs Of Intermittent Locomotion When Turning In Florida Scrub Lizards, Cheyenne Walker

Electronic Theses and Dissertations

Intermittent locomotion is a commonly used escape strategy with a wide array of potential benefits. Pausing may aid in locating a predator, crypsis, lowering energy costs, and avoiding obstacles. Turning may also benefit from intermittent locomotion by allowing an animal time to assess its surroundings; therefore, decreasing the chances of making a mistake and/or stumbling. Florida scrub lizards live in environments with a variety of obstacles such as turns. The goal of this study is to quantify the locomotor behavior and performance by lizards while navigating a 45° or 90° turn. Lizards were run along both a 45° and 90° …

Mortality In Interspecific Hybrids Of Nasonia Vitripennis And Nasonia Giraulti, Bonnie Cobb

Electronic Theses and Dissertations

Nasonia is a parasitoid wasp genus that serves as an emerging model for studying speciation due to an incompatibility between nuclear and mitochondrial genomes between sister taxa. Short generation times, easy rearing in a lab setting, producing large amounts of progeny, and whole genome sequencing make Nasonia is an excellent candidate for studying incomplete reproductive isolation. Nasonia have five chromosomes and exhibit haplo-diploid sex determination in which fertilized eggs develop into diploid females and unfertilized eggs develop into haploid males. Recessive phenotypes are hidden in diploid females but are laid bare in haploid males as there is no interaction between …

Predation Threat In A Variable Landscape: Connecting Predation Risk To Nesting Success For The Seaside Sparrow (Ammospiza Maritima Macgilivraii), Corina D. Newsome

Electronic Theses and Dissertations

Predation, the leading cause of nest-failure in birds, not only exists as a direct threat to nesting success, but may exacerbate other sources of nest mortality. Birds inhabiting Atlantic coastal marshes, such as Seaside Sparrows (Ammospiza maritima; hereafter SESP), are experiencing significant and rapid changes to their habitat, particularly sea level rise (SLR) and encroaching urbanization, that may affect the relative influence of nest predation on overall productivity. For SESPs, SLR presents an inherent threat to nest success in its potential to increase the frequency of nest flooding. In addition to this direct threat, the ability of SESPs …

Species Dispersal Modes In Amphitropical Plant Species Of North And South America, Samera Lemma Mulatu

Honors College Theses

Amphitropical disjunct plants are species that occur in both North and South America but not in the intermediate equatorial region. How amphitropical species dispersed across the Americas to their current distribution remains uncertain. To explain amphitropical distributions, three hypotheses were developed to test that (1) species dispersed successively through island hopping across the tropical zone in temperate microhabitats (= stepping stones), (2) species came to their current distribution through vicariance, or (3) species dispersed by a single long distance dispersal event. Twenty-five species were studied to infer their historical distributions with species distribution models in MaxEnt. Distribution models for each …

Steady Heartbeat: Field And Laboratory Studies Indicate Unexpected Resilience To High Temperatures For The Ribbed Mussel Geukensia Demissa, Ashlyn N. Smith Ms.

Honors College Theses

Salt marshes are important ecosystems found along the coast of Georgia. Salt marshes are hosts to diverse organisms that interact with each other to promote many ecosystem services, such as storm buffering and flooding, and absorption of excess nutrients. Among these diverse organisms is the ribbed mussel, Geukensia demissa. Mussels are a foundation species in this intertidal landscape, and without them the whole salt marsh would be negatively affected. The purpose of this investigation was to explore the thermal stress response of G. demissa to rising temperatures. Mussels were collected from three locations that were landlocked, close to a …

Predator-Based Selection And The Impact Of Edge Sympatry On Components Of Coralsnake Mimicry, Lauren E. Wilson

Electronic Theses and Dissertations

Studying warning coloration and mimicry is an effective way to understand predator-driven selection and phenotypic diversity. The presence (sympatry) or absence (allopatry) of a toxic model plays a role in shaping mimetic phenotypes. However, the impact of edge sympatry and allopatry on predation of mimetic phenotypes is not well understood. We studied coralsnake mimicry to test how edge sympatry and allopatry affect predation on mimetic phenotypes. Specifically, we tested 1) if overall attack rates varied with edge sympatry of coralsnakes 2) which color patterns conferred a fitness advantage 3) which specific mimetic signal components are important in driving predatory attacks …

Plasticity And The Impact Of Increasing Temperature On A Tropical Ectotherm, Adam A. Rosso

Electronic Theses and Dissertations

Organisms may respond to climate change through behavior, genetic adaptation, and/or phenotypic plasticity. Tropical ectotherms are thought to be especially vulnerable to climate change because most have a narrow range of thermal tolerance while living close to their upper thermal tolerance limits. Additionally, many tropical species live in closed-canopy forests, which provide homogenous thermal landscapes that prevent behavioral compensation for stressfully warm temperatures. Finally, tropical ectotherms are thought to have decreased capacity for phenotypic plasticity because they have evolved in thermally stable environments. We tested gene expression patterns and phenotypic plasticity in the Panamanian slender anole by a) measuring changes …

A Multi-Scale Investigation Of Habitat Selectivity In Coastal Plain Stream Fishes, Hayley A. Robinson

Honors College Theses

Studying the habitat use of Coastal Plain fishes enables us to develop a deeper understanding of how fishes thrive in this highly variable environment. Based on previous research by Dr. Roberts and his students, Coastal Plain fishes seem to sort into two groups: (1) species selecting stream reaches that continue to flow throughout the summer (i.e., fluvial species [F]) and (2) species occurring in streams that may stop flowing in late summer (i.e., nonfluvial species [NF]). For this study, I took a detailed look at eight of these species, spanning the F-NF gradient, and asked which environmental variables (e.g., water …

Ecomorphological Variation Among Redbreast Sunfish Populations Of The South-Eastern United States, Grayson Ariel Walker

Honors College Theses

Individual populations of a species will morphologically adapt to their surrounding environment. It has been noted in the past that when species are placed under similar environmental conditions, they will evolve similar morphological structures and shape variation to overcome those obstacles. Redbreast sunfish (Lepomis auritus) were sampled from three different ecoregions (mountainous, Piedmont, and coastal plain) of 4 different isolated river basins in the southeastern North America. It was hypothesized that across basins, populations would show convergent morphological adaptations to mountain, piedmont, and coastal plain condition. I indexed using site elevation as an independent variable, serving as a …

Comparing Feeding Accuracy Between High And Low Predation Trinidad Guppies, Lydia J. Bonnell

Honors College Theses

Efficient feeding accuracy could increase an organism’s survival. Although local adaptation in Trinidad guppies is common, the effects on accuracy are unknown. Guppies were wild caught in 2015 and 2017, filmed while capturing prey. Accuracy wasn’t different within samples but differed across samples, possibly due to the prey types used.

Identification Of Bird-Associated Nonpoint Sources Of Microbial Contamination In Sediments, Savannah D. Mullins

Honors College Theses

Fecal indicator bacteria (FIB), such as Enterococci, are commonly used to monitor the microbial contamination of recreational beach waters based on standards set by the United States Environmental Protection Agency. Sediment and sand may also harbor FIB and reintroduce these bacteria to the water column. Enterococci may be originated from various non-point sources such as humans and wildlife. Recent literature has shown that avian feces also harbor high concentrations of Enterococci. The purpose of this study is identify the relationship between Enterococci and avian-associated markers in sediments. Sediment samples were collected monthly from four sites at Kings Ferry Beach in …

Inferring Food Web Structure To Identify Seasonal And Longitudinal Patterns In Ogeechee River Invertebrate Communities, Julien Marc Buchbinder

Electronic Theses and Dissertations

Understanding how the structure and function of aquatic communities vary across space and time is essential for proper management of freshwater ecosystems. Current management relies on rapid biomonitoring using metrics of community structure, but metrics that incorporate ecosystem processes and functions are only just beginning to see use in assessment and management. Food webs inferred from known species interactions have been proposed as a method of incorporating function into bioassessment without expending extra effort or sacrificing the cost-effectiveness of current monitoring schemes. To apply food webs in biomonitoring, it is first necessary to understand how communities and food webs vary …

Impact Of Seasonal And Host-Related Factors On The Intestinal Microbiome And Cestode Community Of Sorex Cinereus And Sorex Monticola, Katelyn D. Cranmer

Electronic Theses and Dissertations

The intestinal microbiome of mammals plays a significant role in host health and response to environmental stimuli and can include both beneficial native bacteria as well as parasitic worms. In this study, I examined the intestinal cestode and bacterial communities of two closely related species of shrew, Sorex monticola and Sorex cinereus, over a six month period in 2016. Specimens were collected approximately every three weeks from May to October from the Sangre de Cristo Mountains in Cowles, New Mexico. A total of 79 shrews were prepared with the gastrointestinal tracts removed and flash-frozen in liquid nitrogen. An additional …

Effects Of Climate Variability: A Long-Term Perspective On Leaf Litter Processing In The Ogeechee River, Jose A. Sanchez

Electronic Theses and Dissertations

The Intergovernmental Panel for Climate Change (IPCC) predicts a rise in temperatures and changes to precipitation patterns for the 21^st century. These changes are expected to lead to a higher frequency of extreme events such as drought and floods which lead to the alteration of the hydrology, communities, and processes of freshwater ecosystems. Leaf litter decomposition in stream ecosystems is an important component of the energy and nutrient cycle representing a food source for aquatic organisms. This has made it a tool for assessing long term responses to disturbance due to changes in the assemblage of macroinvertebrates that …

Successional Processes In The Benthic Invertebrate Communities At Gray’S Reef National Marine Sanctuary, Alexis A. Bivens

Honors College Theses

While the process of community development has been studied in terrestrial habitats since the turn of the 20th century, similar information is not as readily available in marine systems. Understanding patterns of community development is essential to predicting recovery potential and to designing effective marine protected areas. In the South Atlantic Bight, invertebrate communities on hard substrata can differ significantly from one rocky outcrop to another, but the factors driving these differences are not well understood. I documented the initial development of the benthic invertebrate community at Gray’s Reef National Marine Sanctuary (GRNMS) to address the prediction that this system …

Testing Viability Of Oligonucleotide Primers On Microsatellite Markers Amplified By Polymerase Chain Reaction On Dermacentor Variabilis Samples From The Bulloch County Region Of Georgia, Usa, Danielle Souza

Honors College Theses

Dermacentor variabilis, more commonly known as the wood tick, or the American dog tick, can be found all over North America. D. variabilis is a common tick in Bulloch county, Georgia, USA, and little is known about the population structure of this population of the species. Microsatellite markers are able to locate sections of the genome and can aid in estimating relatedness among individuals in a population. Six different oligonucleotide primer pairs were published for D. variabilis, however, published and non-published works indicated that not all of those primer pairs were working equally well for PCR. This study is …

Comparison Of Three Benthic Macroinvertebrate Passive Sampling Devices For Non-Wadeable Streams, Kelsey A. Laymon

Electronic Theses and Dissertations

Rivers and streams provide essential ecosystem services to the degree that the monitoring and maintenance of these systems becomes imperative. Biomonitoring provides managers and policymakers with the tools to make informed decisions, and macroinvertebrates are often the object of biomonitoring because they are ubiquitous in most systems and are known to be good indicators of water quality. However, methods for sampling macroinvertebrates in non-wadeable streams (i.e., large rivers) have not been standardized across states and regions and an established method for macroinvertebrate biomonitoring in large rivers of Georgia is not currently available. My study compared macroinvertebrates collected with three types …

Predictors Of Fish Assemblage Structure And Dynamics In Atlantic Coastal Plain Streams, Rebecca Scott

Electronic Theses and Dissertations

Effective management of freshwater fishes requires a mechanistic understanding of the drivers of assemblage composition; in other words, what determines who is where and when. Stream fish assemblages are potentially influenced by environmental factors that act on multiple spatiotemporal scales, but the relative influence of these drivers may vary between geophysically distinct regions. This study sought to determine the patterns and drivers of fish taxonomic and functional assemblage composition in the coastal plain, a region possessing unique hydrologies, faunas, and physiochemical conditions. I addressed this goal using two complementary chapters, both of which utilized environmental and biotic data collected from …

Comparative Floristic Studies Of Georgian Sandhill Ecosystems Reveals A Dynamic Composition Of Endemics And Generalists, James M. Long, John Schenk

Honors College Theses

Sandhill habitats are characterized by sandy, xeric soils that contain a unique assemblage of plants and animals. Similar to the broader long-leaf pine (Pinus palustris) and wire grass (Aristida stricta) ecosystem that sandhills are a subset of, agriculture, development, and habitat modifications have caused sandhill ecosystems to become degraded, putting many species at risk of extinction. Previous studies have focused on diversity within individual sandhills, leaving us with an incomplete understanding of how these communities form, what species are endemic, whether endemics are widespread across sandhills, and how species have adapted to these communities. To gain a more comprehensive understanding …

Inbreeding Depression In The Introduced Spider Latrodectus Geometricus, Margaret A. Howard

Honors College Theses

The brown widow spider (Latrodectus geometricus) is thought to be native to South America or Southern Africa, but its distribution has expanded to most continents by human introduction. In the continental USA, L. geometricus was first documented in south Florida in the 1930’s. In the early 2000’s a population expansion occurred, and this species is now found in Florida, Georgia, South Carolina, Alabama, Mississippi, Louisiana, Texas, and southern California. Introduced species may face many obstacles when establishing a new population. One common obstacle might be severe inbreeding following founder events or genetic bottlenecks. The purpose of this study was …

Determining The Reproductive Patterns Of The Titan Acorn Barnacle (Megabalanus Coccopoma) In Its Introduced Range, Isabel L. Moran Ms.

Honors College Theses

Invasive species are a significant conservation concern given their contribution to native species decline. The barnacle, Megabalanus coccopoma, is a common invasive species in tropical and subtropical regions of both the Pacific and Atlantic oceans. Little is known about the life history and ecology of M. coccopoma, and data on reproductive biology could provide valuable insight into its propensity to establish introduced populations. Most species of barnacle (including M. coccopoma) are hermaphroditic, but self-fertilization is rare in species studied to date. A recent genetic study of introduced M. coccopoma populations in the southeastern US showed high levels of …

Evolutionary Linkage Of Mimetic And Non-Mimetic Color Traits In A Coral Snake Mimicry Complex, John D. Curlis Jr

Electronic Theses and Dissertations

Color polymorphism in aposematic mimicry systems is a perplexing phenomenon for evolutionary biologists, as theoretically the benefits of converging on a model phenotype should constrain the evolution of phenotypic diversity in these systems (i.e., color polymorphism should not occur). Nevertheless, color polymorphism in mimicry systems is prevalent throughout many taxa. In some of these systems, the evolution of color polymorphism results in the existence of non-mimetic morphs, such as those that are cryptic. The case of ground snakes (Sonora semiannulata) is unique in that color polymorphism encompasses both mimetic and cryptic morphs, as well as individual mimetic and …

An Industrial Chemical Used In Coal-Washing Influences Plankton Communities In Freshwater Microcosms, Danielle Turner

Honors College Theses

In 2014, 4-methylcyclohexane methanol (MCHM), an industrial chemical used to wash coal, contaminated drinking water in 300,000 homes in West Virginia, USA and raised concerns about toxicity to humans and freshwater ecosystems. The Centers for Disease Control and Prevention determined that a concentration of 1 ppm was safe for human exposure. Despite the concern for human consumption, it is important to determine if MCHM has negative effects on aquatic organisms in contaminated water, particularly plankton communities that comprise the base of freshwater food webs. I exposed freshwater plankton communities in microcosms to 0, 0.5, 1 or 3 ppm MCHM under …