Evolution Commons^™

Sexual Di(Et)Morphism: Using Experimental Evolution To Test Whether Resource Partitioning Promotes Divergence Of The Sexes In Drosophila Melanogaster, Owen A. Jamieson

Theses and Dissertations (Comprehensive)

Sexual dimorphism has been a long-studied phenomenon in the field of evolutionary biology. Usually, these differences in morphology, physiology and/or behaviour between the sexes are studied through the parsimonious lens of sexual selection. However, there are natural history cases where this lens does not seem applicable. Some species show sex specific morphological traits whose presence may not be due to a direct benefit to reproduction, but a difference in how each sex interacts with the environment and differing selective pressures from the environment on either sex. Darwin even brought up examples of this kind of dimorphism and pondered their existence, …

A Geometric Morphometric Analysis Of Acetabular Shape Variation Across Bat Families, Jordan L. Huff

Electronic Theses and Dissertations

Bats are the only mammals capable of powered flight, and research is concentrated on this adaptation. Their non-flight locomotion has received comparatively little attention. Previous studies show that non-flight locomotor behaviors vary across families. Members of Pteropodidae are efficient climbers but cannot effectively walk, whereas Phyllostomidae and Vespertilionidae are better at terrestrial locomotion but show reduced arboreal capabilities. The non-flight locomotion of Hipposideridae and Rhinolophidae is less understood, although rhinolophids exhibit limited terrestrial locomotion. This study examined whether differences in locomotor behavior are associated with variation in acetabular morphology. A geometric morphometric analysis of acetabular shape was conducted across multiple …

Shape Variation In The Mandible Of The Borophagine Canids And Implications For Predatory Behavior, Benjamin Neavear

Theses, Dissertations and Culminating Projects

The borophagines are an extinct lineage of canids that inhabited North America for more than 20 million years. This group included genera such as Aelurodon, Borophagus, and Epicyon. Borophagines are commonly referred to as “bone-crushing dogs” because their skull morphology converged with that of extant hyenas, predators capable of consuming bone. The purpose of this study was to determine whether convergence was present in the mandible, an anatomical structure strongly correlated with feeding behavior, particularly in the genera Aelurodon and Borophagus. It was hypothesized that most borophagine taxa possessed mandibular shapes similar to those of hyenas. Numerous mandibular characters were …

Morphological Variation Of Lingual Glands In Wild American Alligator (Alligator Mississippiensis) Populations, Benjamin Angalet

Master's Theses

American alligators (Alligator mississippiensis) inhabit diverse aquatic ecosystems including freshwater wetlands, swamps, and estuarine rivers. As apex predators, their physiological resilience has implications for ecosystem stability and long-term conservation. With projected sea-level rise and increasing saltwater intrusion into coastal freshwater habitats, understanding the osmoregulatory capacity of alligators is increasingly important. Unlike marine-tolerant crocodilians such as the saltwater crocodile (Crocodylus porosus), which possess specialized salt-secreting lingual glands in addition to renal and cloacal mechanisms, the morphology and physiological significance of lingual glands in wild American alligators remain poorly understood. This study examined lingual gland morphology and plasma …

Sex Or Survival: Does Wounding Elicit A Somatic Reproductive Tradeoff In Narnia Femorata Males?, Lillian E. Burbulis

Departmental Honors & Graduate Capstone Projects

Animals must partition resources into different life history traits resulting in tradeoffs because resources are finite. A tradeoff is the allocation of resources to one trait over another. Theory states that energy is allocated in a hierarchical fashion. For example, somatic maintenance should be a higher priority than reproduction, resulting in more resources being allocated to somatic maintenance compared to reproductive traits. The metabolic investment hypothesis states that energy must follow a hierarchical order prioritizing somatic maintenance over reproduction. Another hypothesis for energy allocation is the terminal investment hypothesis. This hypothesis states that energy will be allocated to reproduction over …

Variation In Infection Prevalence Of Splendidofilaria Pectoralis Across Alaskan Grouse Populations, Anahi Garcia Valdez, Diego Martinez

Create@State

In recent years, rapid climate change has altered species distributions worldwide and influenced parasite transmission dynamics in wildlife systems. Parasite infections play an important role in shaping patterns of disease distribution across species and populations. Understanding variation in infection prevalence across geographic regions and host demographic groups is essential for interpreting these patterns. Splendidofilaria pectoralis is a filarial nematode that infects the connective tissues of grouse (Aves: Tetraonini) in Alaska and has been moving northward as the climate warms. However, relatively little is known about the variation in prevalence of the nematode across geography and demography. This project examines variation …

Does Shape Matter?: How Salamander Head Morphology Shifts Based On Environment, Caitlyn Pinaga, Naomi Ramirez, Sonia Cerrillo

Posters - 2026

Groundwater salamanders of the genus Eurycea represent a diverse group of amphibians inhabiting the aquifer systems of central Texas, where both surface-dwelling and fully subterranean species coexist. Subterranean habitats impose extreme selective pressures, including complete darkness, limited nutrient availability, and stable environmental conditions, which drive convergent morphological traits such as eye reduction or loss, decreased pigmentation, and elongation of appendages. A key evolutionary pattern seen in these systems is sensory compensation, in which the reduction of one sensory modality, in this case vision, is accompanied by the enhancement of others. In aquatic salamanders, this often involves expansion of the lateral …

Analysis Of Mitochondrial Dna Haplotype Groups For South Texas Canids, Canis Rufus, After Past Hybridization Events, Isabella Lopez

Presentations - 2026

mtDNA: mitochondrial DNA; passed from maternal parent to offspring (Haplotype)

Haplotype:  a group of genes or genetic markers inherited together from a single parent (Haplotype)

Mitochondrial DNA haplotypes specific sequences of mtDNA that is passed exclusively from maternal parent to offspring (Giles et al. 1980)

Pro's:

It is passed unchanged from mother to offspring, meaning it is fairly stable (Giles et al. 1980)

Each cell has multiple mitochondria vs one nucleus , which means mtDNA it is more likely to be recoverable from degraded samples like scat (Templeton et al. 2013)

A Simple And Affordable Protocol To Assess Censer Seed Dispersal: First Confirmation Of The Mechanism In The Genus Solanum, Abigail J. Motter, Christopher T. Martine, Melody P. Sain

Faculty Journal Articles

The censer seed dispersal mechanism, whereby mature fruits are retained on plants and seeds dispersed by mechanical shaking, is among the most specialized wind-aided seed dispersal strategies employed by the flowering plants. An efficient, affordable, and easily repeatable protocol for determining whether a species uses this unusual mechanism of seed dispersal is lacking. Our focal species, Solanum tudununggae, is one of just two Solanum species (in a fleshy-fruited genus of ca. 1200 species) hypothesized to use this dispersal mechanism as a means to move seeds farther from parent plants than would gravity alone.

Stress And Reward Interactions In Substance Use Disorder: An Evolutionary Mismatch Framework, Nicholas L. Castrucci

Honors Theses and Capstones

Substance use disorder (SUD) is a major public health concern characterized by compulsive substance use despite adverse consequences. While contemporary models emphasize biological, psychological, and environmental contributors, stress- and reward-related systems are often examined in isolation. This review integrates these systems within an evolutionary mismatch framework to examine how chronic stress exposure and repeated substance use increase vulnerability to addiction. Stress and reward systems are evolutionarily conserved but may become chronically dysregulated under modern conditions characterized by persistent psychosocial stressors and highly potent rewarding stimuli. This is associated with converging neuroadaptations across stress and reward circuitry, resulting in altered affective …

Analysis Of Alternative Oxidase In Non-Angiosperm Plants, Anissa M. Francis

Theses and Dissertations (Comprehensive)

Alternative oxidase (AOX) is a mitochondrial terminal oxidase that provides an alternative pathway for electron transport, allowing plants to maintain respiratory flexibility under environmental stress conditions. While AOX has been extensively studied in angiosperms (flowering plants), little is known about its distribution and conservation in non-angiosperms. Based on gaps identified in the literature, this thesis investigated the distribution of AOX across non-angiosperm plant lineages. Although AOX is present in many green algae and is therefore considered to be an ancient protein that originated before the existence of non-angiosperm plants, it remains unclear whether the protein is uniformly distributed across these …

A Novel 3d Imaging Approach To Study Evolutionary Innovations In Solanaceae Inflorescences, Devin L. Jackson, Joonseog Kim, Wenheng Zhang Dr.

Undergraduate Research Posters

Understanding the relatedness of angiosperms and the evolution of their inflorescence remains challenging, as these structures are highly modified and prone to convergent evolution. The current research describing inflorescence architecture, whether genetically or morphologically focused, typically relies on text based explanations, 2D images, or 3D based models created with CAD modeling software. This creates a disparity in the reader's understanding of these models since descriptions rely heavily on the author's interpretation of the inflorescence. The goal of our study is to bridge this disconnection by producing anatomically and color-correct 3D inflorescence models using Solanaceae flowers that readers can explore directly, …

Sex In Plants: Birth, Death, And Trying To Survive In Changing Climates, Elena M. Meyer

Theses and Dissertations

Plant mating systems are key determinants of fitness. Angiosperms exhibit a wide variety of reproductive strategies, including self-fertilization (or selfing), outcrossing, and mixed mating. It has been estimated that up to 43% of plant species are capable of selfing, and selfing has been hypothesized to provide reproductive assurance where opportunities for mating may be limited, such as in marginal environments. However, questions regarding the overall distribution of selfing rates across angiosperms, the maintenance of mixed mating in the face of inbreeding depression, and the impact of self-fertilization on diversification rates remain incompletely resolved. Here, we explore the dynamics of self-fertilization …

Phylogeography, Fungal Host Specificity, And Fitness In The Corallorhiza Maculata Species Complex, Hana Thixton-Nolan

Graduate Theses, Dissertations, and Problem Reports (ETD)

Mycoheterotrophic plants exploit fungi for most or all nutritional needs, providing a compelling system to address the evolutionary consequences of genome reduction, population-level variation, and germination requirements. I am using the widespread Corallorhiza maculata species complex to address questions of genomic variation, fungal host specificity, morphological variation, and germination requirements across the broad geographic range from Mexico to northern North America. This complex contains C. bulbosa, C. macrantha, and C. mertensiana, the latter with three varieties (maculata, occidentalis, and mexicana). These taxa vary in flowering time, floral morphology, and fungal associations. However, the degree …

Systematics Of Disk-Winged Bats (Thyroptera), Courtney L. Klumpp

Capstone Showcase

This thesis investigates the evolutionary relationships among disk-winged bats in the genus Thyroptera, a small group of Neotropical bats known for the adhesive suction disks on their wings and feet that allow them to roost inside tightly rolled leaves. The distinctive morphology and behavior of these bats have not been extensively documented, and their phylogenetic relationships remain only partially resolved. The goal of this research is to better understand how these species are related to one another and to determine whether the five recognized species of Thyroptera form a single monophyletic group. To address this question, morphological and genetic …

Dosage Sensitivity And The Evolution Of Dosage Compensation: Tests Of The Insensitive Sex Chromosome Hypothesis In Flour Beetles, Shana Pau

Biology Dissertations

Sex chromosome evolution generates imbalances in gene dosage that can disrupt gene expression and organismal function. These imbalances are often resolved through dosage compensation mechanisms, yet the factors that drive the emergence and diversity of these systems remain poorly understood. This dissertation addresses a central question in evolutionary genomics: what governs the evolution of dosage compensation?

Focusing on dosage sensitivity as a potential driver, I evaluate the Insensitive Sex Chromosome Hypothesis (ISCH), which predicts that chromosome-wide compensation is more likely to evolve in genomic contexts that are not depleted of dosage-sensitive genes. Using flour beetles (Tribolium spp.) as a …

A Review Of Mockingbird Song, Jacqueline Milander

Student Theses

The northern mockingbird (Mimus polyglottos) is known for its large repertoire and highly versatile song patterns.  It is a frequent mimic that is thought to continue learning sounds from its environment for the duration of its life.  Utilizing available song studies, this is a comprehensive review of northern mockingbird song, including learning, mimicry, repertoires, song dependence on seasonal cyclicity, and song function, particularly interspecific territoriality. While much discussion has surrounded the idea that northern mockingbirds engage in interspecific territoriality and that vocal mimicry functions in intersexual selection, this review provides new insight into the possibility that latitudinal differences among populations …

A New Dioecious Bush Tomato, Solanum Nectarifolium (Solanaceae), From The Northern Tanami Desert, Northern Territory, Australia, With Reassessment Of S. Ossicruentum And A Change In The Circumscription Of S. Dioicum, Christopher T. Martine, Kym Brennan, Jason T. Cantley, Aiden Webb, Geoffrey Newton

Faculty Journal Articles

A new species of functionally dioecious bush tomato from the “Solanum dioicum + S. echinatum group” of Solanum subgenus Leptostemonum is described. Solanum nectarifolium Martine & Brennan, sp. nov., is a member of the taxonomically challenging Solanum dioicum W.Fitzg. species complex in Australia and differs from other species in the group by the presence of prominent and conspicuous extrafloral nectaries on the abaxial leaf surfaces, a tinge of purple on the new growth and young fruiting calyces, and curved prickles on young stems. Although fairly well represented in herbarium collections, this new taxon has historically been treated as a …

Function Of Drosophila Melanogaster Domesticated Transposable Element Protein Dplg3 In Oogenesis And Total Fitness, Aron Herrera

2025 Fall Honors Capstones Projects - Archive

Transposable elements (TEs) are selfish DNA segments capable of self-replication and reinsertion within genomes, often harming hosts. Rarely, host genomes can adopt TEs and use their proteins for new cellular functions through molecular domestication. One example primarily expressed in Drosophila melanogaster ovaries is DPLG3. Previous Betrán Lab students generated DPLG3 loss-of-function flies and found that their ovaries misregulated one primordial and 14 testis-specific genes, leading to variable ovarian malformations. However, it is unclear when during oogenesis these misexpressions occur. We will extract RNA from non-rudimentary ovaries at early and late stages to generate cDNA for qRT-PCR analysis of three …

Population Structure Analysis Of Four Basal Higher-Attines Using Bioinformatic Approaches, Gabriel Mcdanield

Biology Theses

Metapopulations within the family Formicidae are unique among other animals due to the large colonies they build, and the mating strategies required to fertilize a specialized reproductive caste that will often produce young for the life of the colony. One group of ants, the fungus-gardeners (tribe Attini). The population structure of North American non-leafcutting, fungus-gardening ants has been understudied, especially in the southwest of the United States. Additionally, not much is known about their dispersal biology, so the dynamics of dispersal of these species and how they affect population structure is likewise not well known. To shed light on the …

Multilevel Selection In The Margins: A Review Of Its Representation In Undergraduate Biology Textbooks, C. A. Greene, S. J. Mcpeek, L. Mitchem, A. B. Clark, Vincent A. Formica

Biology Faculty Works

Multilevel selection (MLS) is a foundational framework that expands the concept of natural selection beyond the traditional focus on individuals or genes to larger units, like groups. Despite strong empirical support and applications in a broad range of biological fields, MLS, often referred to as group selection, has a controversial history, which has impeded its wide use and led to incorrect inferences on the sources and strength of selection. Here, we explore how MLS is currently presented to undergraduate biology students by analyzing the content of nine commonly used Evolutionary Biology and Animal Behavior textbooks. We ask whether and how …

The Inherent Values Of Observation And Description: A Case Study In The Spiny Solanums Of Australia, Christopher T. Martine

Faculty Journal Articles

The basic exploratory effort of doing descriptive biology is an avenue by which we can deepen our knowledge about taxa and the natural phenomena that drive their diversification. As Conniff (2011) wrote in The species seekers, “we still live in the great age of discovery”, and much like that historically recognized period of the eighteenth and nineteenth centuries there remains today a distinct need for the sort of work that might have been attributable to the naturalists of that time. The careful observation of how organisms go about their lives, including how they interact with one another …

Age-Dependent Changes In Reproductive Behaviour And Success In A Long-Lived Beetle (Bolitotherus Cornutus), C. A. Greene, L. D. Mitchem, Vitor Dos Anjos , '21, E. D. Brodie Iii, Vincent A. Formica

Biology Faculty Works

Age-related changes in behaviors often result in shifts in an individual’s competitive ability, reproductive success, and fitness. However, how mating behaviors, aggression, and mating success simultaneously change as individuals age in natural populations remains understudied. Investigating these age-dependent effects in wild populations could reveal how age-specific patterns shape social dynamics and influence natural selection. In this study, we ask how behaviors associated with mating and reproductive success vary across age in a wild metapopulation of a long-lived beetle, Bolitotherus cornutus. We used both cross-sectional and longitudinal data from a multi-year field study of individually marked beetles to investigate how …

Evaluating The Environmental Determinants Of Tadpole Mouthpart Deformities, Nicholas J. Canfield

Research from the Berry Summer Thesis Institute, 2025

Amphibians are among the most threatened group of animals on the planet, with over 40% of living species facing an extinction risk. These organisms are highly sensitive to environmental change due to their highly permeable skin and complex life cycle that exposes them to stressors in both aquatic and terrestrial ecosystems. Amphibian populations that are closely monitored can serve as valuable bioindicators of environmental health because they typically respond rapidly to habitat degradation, decreased water quality, and changes in climate. Tadpoles in particular may act as a “canary in a coal mine” for aquatic ecosystems because they easily develop anatomical …

Male Mating Preference For Larger Females Does Not Vary Among Age Classes In The Long-Lived Beetle Bolitotherus Cornutus, G. M. Jiron, C. A. Greene, E. D. Brodie Iii, Vincent A. Formica

Biology Faculty Works

Theory and past experimental work suggest that as males age, the strength of their mate preference should decrease. However, the empirical work investigating this question has primarily been conducted in insects that have very short life spans and often live for just a single mating season. This leaves a gap in our understanding of the relationship between male mate preference and age across taxa, as age can conflate with other ecological changes in a single mating season. In this study, we ask how the strength of preference for large female body size changes as males age in a long-lived insect, …

Applying Transcriptomics For Technology Development And Conservation In North American Marine Organisms, Cory Von Eiff

Dissertations

RNA biology is a rapidly expanding field, with many avenues of discovery among marine organisms. In this study, we analyze both mollusks and sawfish. First, we perform an evaluation of sRNA biogenesis pathways throughout Mollusca, with emphasis on the easter oyster, Crassostrea virginica. Understanding these molecules prescribes RNAi-based gene silencing approaches, benefiting genetic investigation and biotechnology. Similar to other animal groups, mollusks have conserved microRNAs (miRNAs), with some shared with ecdysozoans and deuterostomes; however, there is no evidence of an endogenous small interfering RNA (siRNA) pathway. These results suggest that long double-stranded RNA (dsRNA)-based RNAi is not appropriate for gene …

The Island Biogeography Of Mangrove-Dwelling Vertebrates: Isolation, Specialisation, And Extinction, Jian Xiong David Tan

Biology ETDs

Mangroves are highly dynamic ecosystems that are widely distributed across the coastlines of the tropics and subtropics. Despite their low plant diversity, mangroves host a disproportionately high number of terrestrial vertebrate taxa. However, mangrove specialists — taxa that only occur in mangrove habitats — exhibit a global distribution that is incongruous with the broader background distribution patterns of mangrove-associated fauna, exhibiting higher diversity in Australia and Southeast Asia. This dissertation therefore aims to assess how the diversity and distribution of mangrove specialist fauna may have been shaped by the historical biogeography of mangroves, and the effects of mangrove specialisation on …

​​Site Fidelity Is Associated With The Social Experience Of Forked Fungus Beetles (Bolitotherus Cornutus), Joo Yeon Kim , '22, C. W. Wood, E. D. Brodie Iii, Vincent A. Formica

Biology Faculty Works

Consistently returning to or remaining within a specific location, a behavior known as site fidelity, is a useful metric for quantifying animal space use. When multiple individuals display similar site fidelity patterns, they are likely to interact, shaping the degree and quality of their social interactions. However, the link between the expression of site fidelity behavior and an individual’s social experience has not been thoroughly investigated. In this study we examined (1) how intrinsic individual properties (body size and sex) predicted variation in site fidelity and (2) whether site fidelity was linked to the social experience of individuals in wild …

Field Journal: The Excluded Middle, Carrie E. Kouts

Masters Theses

What does it look like to engage with organisms and landscapes at the periphery of anthropocentric value structures? How does one break the internalized myth that the “built” environment is excluded from the natural world? When does a hyper-mobile and hyper-commodified society confront the exponential crisis of animal death? Within this series of journal entries, field notes, collection observations, weird prose, and sensory musings, one will find questions on the nature of being human and the complex narratives of care we encounter in a world shared with more-than-humans. Each handwritten vignette and photograph from daily life weaves a non-linear and …

Network Analysis Of Antimicrobial Resistance In Staphylococcus Aureus: Characterization Of Hub Genes And Their Functional Implications, Md Imran Hasan, Davida Smyth, Jeong Yang, Ashley Teufel

Masters Theses (Archived)

Antimicrobial resistance is a major cause of morbidity and mortality in patients with S. aureus infections. In this study, we analyzed genes, molecular mechanisms, and pathways driving drug resistance in S. aureus using network analysis. Using whole-genome sequencing (WGS) data and systems biology approaches, we identified 229 AMR-associated genes and constructed a protein-protein interaction network among these genes. Through network topology and functional enrichment analyses, we not only confirmed their association with resistance, but also highlighted the central roles of these genes in resistance pathways, such as efflux, target replacement, and target protection, which are directly linked to multiple drug …