Ecology and Evolutionary Biology Commons^™

Offspring Size-Number Tradeoffs And Food Quality Feedbacks Impact Population Dynamics In A Daphnia-Algae System, Ryan Wenkus

College of Science and Health Theses and Dissertations

Population fluctuations can be affected by a number of extrinsic and intrinsic factors, but few manipulative experiments have been conducted that can isolate these effects in consumer-resource systems. Extrinsic factors such as weather patterns or food availability can impact consumer growth and reproduction. Additionally, intrinsic factors relating to life history can have significant impacts on population growth rates. A fundamental principle of life history theory is that individuals are limited by trade-offs between survival and reproduction, and there are a variety of combinations, given environment and physiological limitations, that should maximize lifetime reproductive output. Reproductive strategies vary between species, but …

Evaluating The Myth Of Allelopathy In California Blue Gum Plantations, Kristen Marie Nelson

Master's Theses

It is widely accepted that allelopathy is not only significant, but more or less singular, in the inhibition of understory vegetation in California Eucalyptus globulus (blue gum) plantations. However, there is no published documentation of allelopathy by blue gums against California native species. Here, we present evidence that germination and early seedling growth of five California native species are not inhibited by chemical extracts of blue gum foliage, either at naturally-occurring or artificially concentrated levels. In the greenhouse, seeds were germinated in field-collected soil from mature blue gum plantations and the adjacent native, coastal scrub communities. In petri plates, seeds …

Phylogenetic Analysis Of Human Cytomegalovirus Pus27 And Pus28: Ascertaining An Independent Or Linked Evolutionary History, Jessica A. Scarborough

Undergraduate Honors Theses

Human cytomegalovirus (HCMV) is a widespread pathogen that is particularly skilled at evading immune detection and defense mechanisms, largely due to extensive co-evolution with its host’s immune system. One aspect of this co-evolution involves the acquisition of four virally encoded GPCR chemokine receptor homologs, products of the US27, US28, UL33 and UL78 genes. G protein-coupled receptors (GPCR) are the largest family of cell surface proteins, found in organisms from yeast to humans. In this research, phylogenetic analysis was used to investigate the origins of the US27 and US28 genes, which are adjacent in the viral genome. The results indicate that …

Preserving Biodiversity For A Climate Change Future: A Resilience Assessment Of Three Bay Area Species--Adenostoma Fasciculatum (Chamise), Arctostaphylos Canescens (Hoary Manzanita), And Arctostaphylos Virgata (Marin Manzanita), Alison S. Pollack

Master's Projects and Capstones

Anthropogenic climate change is an undeniable threat to the future of the natural world and human civilization. These shifts will have profound impacts on vegetation, especially for species endemic to isolated regions or sensitive to climate change factors. However, species resilience can predict success into the next century. Resilience is defined as the ability to withstand climate change factors, whereas vulnerability is defined as susceptibility to climate induced stress or damage.

Chaparral and coastal scrub ecosystems within the Bay Area of California provide a unique context for examining resilience, as many species are adapted to high temperatures, drought, and wildfire—all …

Determining The Pollination Mechanism Of A Problematic Invasive Species In The Gulf South: Triadica Sebifera, Jennifer Wester Clark

University of New Orleans Theses and Dissertations

Understanding the ecology of invasive species is vital to curb the homogenizing of ecosystems, yet the pollination mechanisms of the Chinese tallow tree (Triadica sebifera) in its introduced habitat remain ambiguous. This study examines self-pollination, wind pollination, and flower-visiting insects of tallow in a bottomland hardwood forest and Longleaf pine savannah in the U.S. Gulf South. These data suggest that self-pollination and airborne pollination are possible, but likely rare occurrences, although the possibility of apoxisis was not investigated. Seed production in exclusion experiments was significantly less than in open-pollinated flowers, and wind dispersal of tallow pollen dropped to …

The Gowanus Canal: Delving Into The Murky And Mysterious Waters Of Brooklyn’S Toxic Canal, Victoria L. Von Ancken

Student Theses 2015-Present

Like many environmental issues we face today, the Gowanus Canal began as a hopeful tale. It was envisioned as a promising cargo transportation waterway in Brooklyn, New York. However, due to reckless planning with little thought for the future, the canal slowly began to have a negative effect on its surrounding landscape and community, as well as abandoning its initial purpose, and ultimately sitting stagnant in the neighborhood. Today, the canal is a large environmental problem we face and is in great need of cleanup. The canal is a prime example of a lack of planning and consequential detrimental effects …

Population Projection And Habitat Preference Modeling Of The Endangered James Spinymussel (Pleurobema Collina), Marisa Draper

Senior Honors Projects, 2010-2019

The James Spinymussel (Pleurobema collina) is an endangered mussel species at the top of Virginia’s conservation list. The James Spinymussel plays a critical role in the environment by filtering and cleaning stream water while providing shelter and food for macroinvertebrates; however, conservation efforts are complicated by the mussels’ burrowing behavior, camouflage, and complex life cycle. The goals of the research conducted were to estimate detection probabilities that could be used to predict species presence and facilitate field work, and to track individually marked mussels to test for habitat preferences. Using existing literature and mark-recapture field data, these goals were accomplished …

Photosynthetic Characterization Of Invasive Plant Diversity In Los Angeles County From 1830-2010, Lauren E. Pangburn, Erich Eberts, Victor Carmona-Galindo

Honors Thesis

The increase in atmospheric CO₂ levels due to climate change may greatly impact invasive plant species, which are non-native organisms that spread unchecked in space and negatively impact native organisms. The success of these invasives may be related to specific traits, such as their photosynthetic pathway. We acquired the specimen information for invasive species registered in the Consortium for California Herbaria of the University of California Berkeley to evaluate the community dynamics of 1,000 invasive species in Los Angeles County. We found that both diversity and richness of invasive plant species has increased over a period of 180 years. …

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 …

Investigation Of The Enviromental Factors Associated With The Temporal Abundance Of Lutzomyia Anthophora On A Ranch Near Poth, Texas, Maha Alshhrany

Theses & Dissertations

Leishmaniasis is caused by infection with protozoan parasites within the genus Leismania transmitted by the bites of female sand flies within the genus Lutzomyia in the New World. This study investigated the seasonal abundance of sand flies and evaluated the correlation of temperature with abundance data. Sand flies were collected at the Garrison ranch near Poth, Texas (28° 57’ 10” N; 98° 7’ 28” W) from May in 2014 through October, 2015. Recorded highest abundance of sand flies in 2014 was in October, 2 females Lu.anthophora and 5 males Lu.anthophora were captured producing 0.58 sand flies /trap night, while, mean …

Natural Selection By Insect Pollinators And Seed Predators On Floral Head Traits Of Helianthus Grosseserratus (Sawtooth Sunflower), Jason Stephen Servi

Theses and Dissertations

Flowering plants must invest energy and resources to produce floral displays that are attractive to pollinators, but these same displays may also attract detrimental insects. How floral traits are shaped by the preferences of both pollinators and herbivores/seed predators is not fully understood. Using Helianthus grosseserratus (sawtooth sunflower) as my study species, I investigated these conflicting selective pressures on floral head traits through a 2-year study in a large, unbroken tract of mesic prairie in Wisconsin. In the first season, I followed individual heads over time and recorded insect visitation patterns and phenological changes to floral head traits. I also …

Hybridization, Population Genetic Structure And Gene Expression In The Genus Boechera, Martin Peter Schilling

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

When we look at life on earth, we can see a lot of different life forms, but we still do not fully understand how these different life forms came to be and at which points in time these life forms began to be different enough from each other so we could call them by different names, or species. Some groups of species on earth, especially plants, seem to reproduce with each other, even though they are already very different from each other so that we call them different species. This process is called hybridization, and it can stir up the …

Blood Parasite Infection And Plumage Elaboration Of Migratory And Resident Populations Of The Common Yellowthroat, Rebecca Leigh Schneider

Theses and Dissertations

In birds, blood parasite diversity varies with latitude, seasonal changes, and habitat type. As a consequence, migratory populations of birds have greater exposure to parasites during their annual cycle than resident populations. Parasite infections may negatively affect the health of individuals which could, in turn, affect the development of elaborate plumage ornaments. We compared migratory (Wisconsin) and resident (Florida) populations of common yellowthroats (Geothlypis trichas) to test whether migratory birds in Wisconsin have more prevalent, intense and diverse infections of blood parasites and subsequently less elaborate ornamentation than their resident counterparts in Florida. As predicted, we found higher prevalence, intensity …

Estimating Avian Populations With Passive Acoustic Technology And Song Behavior, Stephanie C. Prevost

Masters Theses

The need for improvements in avian wildlife monitoring efficiency, accuracy, and scope has led to use of new technologies such as autonomous recording units (ARUs). As a monitoring tool, passive acoustic recording has numerous benefits, but it is still limited to use in human-accessible areas. There is also need for monitoring technologies in areas that are inaccessible. Military installations, which host a disproportionately large number of threatened, endangered, and at-risk species compared to other federal lands, pose the accessibility problem with sizeable impact areas that are too hazardous for humans to access. This thesis introduces the Balloon Aerial Recording System …

Relationships Between Nutrients, Periphyton Abundance, And Benthic Macroinvertebrate Scrapers In Ozark Highland Streams, Harrison Smith

Biological Sciences Undergraduate Honors Theses

We collected samples from seven Arkansas streams during the months of August 2014 and February 2015 with the objective of determining possible relationships between nutrients, periphyton abundance and benthic macroinvertebrates. We hypothesized that periphyton would be positively associated with nutrients, and that increases in periphyton biomass would increase the abundance and diversity of benthic scraper families. Samples were collected from three transects at each site. The periphyton was analyzed for carbon, nitrogen, phosphorus, and ash free dry mass and Chl-a content. Macroinvertebrates families belonging to the feeding group of grazers/scrapers were compared with water column and periphyton nutrient concentrations, as …

Stream Benthic Algal Relationships With Multi-Metric Indices Of Sensitivity, Exposure, And Vulnerability To Watershed Land Use Change, With An Emphasis On Unconventional Natural Gas Development, Hannah J. Verkamp

Biological Sciences Undergraduate Honors Theses

Unconventional natural gas (UNG) is harvested using a unique fossil fuel extraction method that uses horizontal drilling and hydraulic fracturing techniques. The combined methods have expanded the industry both nationally and globally, and development has the ability to transform landscapes and impact freshwater resources. Natural gas wells are often near streams, yet substantial knowledge gaps remain as to how and the extent to which development affects surface waters. Stream algal biomass can respond positively to anthropogenic stressors associated with different types of land use, including agriculture. Benthic algal biomass can also positively correlate with UNG well density and proximity to …

Are We Missing The Forest For The Trees? Quantifying The Maintenance Of Diversity In Temperate Deciduous Forests, Kathryn Barry

Theses and Dissertations

One of the most pressing questions of community ecology is: Why do we have so many species? Over 100 hypotheses have been proposed to answer this question for woody plants over the past 70 years, yet there remains no consensus among community ecologists. In this dissertation, I explore the evidence supporting several different hypotheses (Chapter 1). I provide evidence that negative density dependence, where individuals perform poorly near members of their own species, may only be relevant for canopy tree species (Chapter 2). Understory species do not demonstrate negative density dependence while canopy trees demonstrate negative density dependence that increases …

Response Of Leukocyte Profiles To Corticosterone Manipulation In The Prairie Rattlesnake (Crotalus Viridus), Jill E. Guillette

Biological Sciences Undergraduate Honors Theses

Prior work has shown that when animals are stressed they have altered leukocyte profiles. The use of leukocyte profiles could provide an inexpensive and efficient method for determining stress. Here we present a validation of the use of leukocyte profiles for showing induced stress in Prairie Rattlesnakes (Crotalus viridus). Snakes (N=19) with masses ranging from 682g to 137g were used in a repeated measures design to examine the effect of hormone manipulation on leukocyte profiles. During each trial snakes were dosed with either corticosterone and sesame oil (1.1µg/g) or only sesame oil. Prior to dosing, baseline blood samples …

Consequences Of Loss Of An Abundant Pollinator: An Experimental Study, Allysa Hallett

Theses and Dissertations

Pollinator populations are declining worldwide, and this may lower the quantity and quality of pollination services. Since pollinators often compete for floral resources, loss of an abundant pollinator species may release others from competition and potentially alter floral visitation rates. We explored how the removal of a frequent pollinator, bumble bees, influenced pollination success of whorled milkweed (Asclepias verticillata). In three small and three large populations we quantified pollinator visitation rates and pollination success for control plots and for plots where bumble bees were experimentally excluded. We found that exclusion of bumble bees did not reduce A. verticillata pollination success. …

Physiology And Genetics Of Starvation-Selected Drosophila Melanogaster, Christopher Michael Hardy

UNLV Theses, Dissertations, Professional Papers, and Capstones

In nature, organisms have evolved to survive in stressful environments. This has driven organisms to adopt a wide range of unique adaptations. Investigating the mechanistic basis of these adaptations is an important tool for discovery that has led to major advances in science and medicine.

We study how organisms survive life without food, or starvational stress. Environmental stressors have shaped the quantity and quality of food sources across the globe. This has led to vast differences in the ability of some organisms to tolerate starvation over others. Many researchers have used Drosophila melanogaster as a model to study global patterns …

Insights Into The Introduction Histories And Population Genetic Dynamics Of The Nile Monitor (Varanus Niloticus) And Argentine Black And White Tegu (Salvator Merianae) In Florida., Jared Price Wood

Electronic Theses and Dissertations

This dissertation examines the population genetic dynamics of two Florida invasives: the Nile monitor (Varanus niloticus) and Argentine black and white tegu (Salvator merianae). I also provide insights into the introduction histories of both species. This study was developed as part of a collaborative effort with the Florida Wildlife Commission to expand our knowledge of these highly detrimental, invasive lizards. All research activities involving animals and animal tissues were approved by the University of Louisville’s Institutional Animal Care and Use Committee (IACUC Proposal #: 12024). I start with a brief introduction into what makes invasive species …

Sources Of Ecologically Important Trait Variation In Mosquitofish (Gambusia Affinis And Gambusia Holbrooki), Heather Ann Arnett

Electronic Theses and Dissertations

The study of contemporary evolution and eco-evolutionary dynamics is classically defined in terms of genetic evolution, but the actual suite of processes driving contemporary trait change is likely much more complex than often credited. This dissertation considers additional mechanisms of trait change that might be important to an emerging model system for study of contemporary evolution and eco-evolutionary dynamics. Specifically, the research focuses on phenotypically plastic and demographic trait variation in Eastern and Western Mosquitofish (Gambusia affinis and G. holbrooki) facing the major ecological gradient of predation risk. Plasticity experiments employed a common-garden rearing design to manipulate fish …

Why Are Students Doing Research? Examining The Motivation Of Students Involved In Undergraduate Research Programs, Andrew Layne Mcdevitt

Theses and Dissertations

Use of self-determination theory (SDT) within the science classroom focuses primarily on ways to integrate intrinsic motivation into students' identity. Experiential learning plays a large role in promoting learning by shaping students' interests, identity, and intrinsic aspirations. This phenomenological research study sought to understand how experiential learning experiences helped influence career aspirations of graduate students within ecological disciplines. By determining how their experiences met three basic psychological needs outlined by SDT (competence, autonomy, and relatedness), we were able to examine which regulators drove motivation.

In the qualitative pilot study, participants developed a genuine enjoyment and appreciation for their discipline as …

Characterization Of Soundscapes In Shallow Water Habitats Of The Florida Keys (Usa) And Their Influence On The Settlement Of Larval Fish And Invertebrates, John R. Butler

Biological Sciences Theses & Dissertations

In recent decades, changes in climate and water quality in Florida Bay and the Florida Keys (FL, USA) caused expansive cyanobacteria blooms that in turn precipitated massive sponge die-offs that drastically altered sponge-dominated hard-bottom communities in south-central Florida Bay. This area served as a model system to explore the effect of ecosystem change and habitat restoration on underwater soundscapes and larval recruitment. I had four main objectives: (1) characterize the underwater soundscapes of three near-shore, benthic habitats: mangrove islands, seagrass meadows, and hard-bottom (Chapter 2); (2) quantify larval settlement within healthy, degraded, and restored hard-bottom areas to test whether habitat …

Naturalization Of Salt Marsh Restoration Sites In The Elizabeth River, Virginia, Assessed By Feeding Activity And Trophic Level Of Mummichogs (Fundulus Heteroclitus), Moriah Anne Good

Biological Sciences Theses & Dissertations

Recent efforts to mitigate environmental issues within the Southern Branch of the Elizabeth River, Virginia, designated a “Region of Concern” by the Chesapeake Bay Program, include several salt marsh restorations. By examining gut contents and stable isotopes values (δ13C and δ15N) from mummichogs (Fundulus heteroclitus), the functional equivalency of restored salt marshes compared to natural marshes was measured. In July 2013 I collected mummichogs from three restored and three reference salt marshes in the Southern Branch. Fish were collected for gut content analysis and were analyzed for stable isotopes (δ13C and δ15N).

I removed gut contents from 16 fish per …

A Hitchhiker’S Guide To Invasion Biology: Describing The Ecological Mechanisms Underlying The Range Expansions Of Two Ixodid Tick Species, Robyn M. Nadolny

Biological Sciences Theses & Dissertations

Increasing incidence of many tick-borne diseases have been linked to recent expansions of tick species distributions. Many tick species are expanding their ranges because of anthropogenic changes in the landscape, shifting climatic variables, and increasing populations of suitable host species and tick habitat. Few empirical studies have been performed, however, investigating the ecological mechanisms underlying these range expansions. Ticks are parasitic organisms that disperse across landscape by hitchhiking on hosts, but must then survive in the environment for long periods of time between bloodmeals. Two species of ixodid tick, Ixodes affinis and Amblyomma maculatum, are simultaneously expanding their ranges throughout …

Evolvability Of The Skull: A Study Of Genetic Basis And Integration In The Teleost Craniofacial Skeleton, Yinan Hu

Doctoral Dissertations

As the field of evolutionary biology pivots away from a gene-centric view of how adaptive evolution proceeds, renewed emphasis is placed on the origin of phenotypic variation. Understanding the developmental processes that underlie the production of novel traits, and how they might influence evolvability, is considered a primary goal in the on-going “extended evolutionary synthesis”. The following dissertation explores these questions in the context of adaptive radiations in fish, with a focus on morphological variation in the craniofacial skeleton. Specifically, the first chapter investigates the genetic and developmental basis of shape (co-)variation in the feeding apparatus of African cichlid fishes, …

When Human-Leopard Conflict Turns Deadly: A Cross-Country Situational Analysis, Julie S. Viollaz

Dissertations, Theses, and Capstone Projects

Habitat destruction and pollution are two of the main causes for the decline of the planet’s biodiversity. Yet environmentalists are now recognizing that illegal wildlife killings, both poaching and retaliatory killings due to human-wildlife conflict, are perhaps the next major threat. Biologists have researched illegal killings and their effect on species conservation, but few researchers have applied criminological principles of crime reduction to them. This research will explore the situational factors that drive retaliatory leopard killings in parts of South Africa, Kenya, and India. These factors, human and environmental, include local expectations from wildlife, sensitivity to environmental issues, communication between …

Tests Of Reproductive Isolation Between The Fishes Fundulus Heteroclitus And F. Grandis, Ruthie E. Barbas

UNF Graduate Theses and Dissertations

The closely related killifishes Fundulus heteroclitus and F. grandis hybridize in a small region where their ranges overlap in coastal northeastern Florida. Hybrids of these species are rare in frequency within the contact zone, suggesting the presence of relatively strong reproductive isolation between these species. The objective of this study was to elucidate barriers to reproduction between F. heteroclitus and F. grandis in the lab, as well as to quantify the relative strengths and contributions of various isolating barriers. Pre-zygotic (mating and fertilization) and post-zygotic (hatching) barriers were investigated by performing a variety of choice and no-choice laboratory mating experiments. …

Independent Origination Of Floral Zygomorphy, A Predicted Adaptive Response To Pollinators: Developmental And Genetic Mechanisms, Ghadeer Bukhari, Wenheng Zhang

Theses and Dissertations

Observations of floral development indicate that floral organ initiation in pentapetalous flowers more commonly results in a medially positioned abaxial petal (MAB) than in a medially positioned adaxial petal (MAD), where the medial plane is defined by the stem and the bract during early floral development. It was proposed that the dominant MAB petal initiation might impose a developmental constraint that leads to the evolution of limited patterns of floral zygomorphy in Asteridae, a family in which the floral zygomorphy develops along the medial plane and results in a central ventral (CV) petal in mature flowers. Here, I investigate whether …