Evolution Commons^™

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 …

How Semiflightless Birds Adapt: A Survey From Barú, Costa Rica, Eli P. Laloudakis

Scripps Senior Theses

When we think of birds, we think of flight. Because of this, scientific research often focuses on how birds evolved flight and how their wings function during flight. However, not all birds can fly or fly well, as wings wax and wane on developmental, seasonal, and evolutionary time scales (Dial and Heers 2021). Consequently, rudimentary wings can be found in developing birds, secondarily flightless or semiflightless birds, birds that undergo simultaneous molts, and extinct theropods with “protowings” (structures that preceded fully functional wings). Secondarily flightless and semiflightless birds often evolve where there is no/low predation, abundant year-round food supply, and …

Overview And Methods Of Molecular Paleontology: A Review, Shelby Touchstone

Williams Honors College, Honors Research Projects

Molecular paleontology—the study of ancient biomolecules preserved in fossils and sediments, including ancient DNA, lipids, and proteins—has motivated researchers since the 1950s, inspiring both scientific inquiry and broader cultural imagination. Think Jurassic Park. This honors thesis presents a comprehensive review of the history, current state, and methods of the field of molecular paleontology. Drawing on peer-reviewed literature and scholarly resources accessed through databases such as EBSCO and Bierce library, this review examines key techniques such as Next Generation Sequencing and amino acid racemization and will go over limitations and controversies in the field. It will also explore potential new …

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 …

Exploring Factors Mediating White-Nose Syndrome In Little Brown Bats, Carly R. Trujillo

Graduate Theses/Dissertations

The little brown bat (Myotis lucifugus) has experienced drastic population declines across North America due to the recent disease white-nose syndrome (WNS). Previous studies have identified putatively adaptive alleles (PAAs) that may give individuals a greater likelihood of survival. However, there could be geographic-specific adaptation, creating different adaptive landscapes. Additionally, there may be energetic trade-offs between disease survival and reproductive output, and it is not clear what the long-term survival outcomes for the species may be as a result. Long-term evolutionary outcomes are unclear because this species has a lifespan exceeding the arrival of WNS and is difficult …

Homoplasy Of Maxillary Orthognathism In Derived Homo, Jared Jordan

Graduate Studies Theses and Dissertations 2026

The evolution of the orthognathic condition in the genus Homo represents a monumental transition toward the facial morphology of modern humans from that of earlier hominins, but the phylogenetic positioning of this transformation remains poorly understood. This study investigated temporal trends in maxillary and mandibular prognathism in the genus Homo, and whether maxillary and mandibular shortening in East Asian H. erectus and later East Asian Middle Pleistocene Homo (e.g., Homo longi) represent independent derivations of orthognathic morphology, thereby making orthognathism a homoplasy in the genus Homo. Using a sample of roughly 109 cranial and mandibular specimens spanning …

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 …

Immunological Surveillance Against Cancer Across Mammals, Orsolya Vincze, Piotr Minias, Alexandre Corthay, Fernando Colchero, Jean-François Lemaître, Louise Maille, Tamás Malkócs, Justus Hagemann, Dalia A. Conde, Samuel Pavard, Antoine M. Dujon, Beata Ujvari, Frédéric Thomas, Amy M. Boddy, Carlo C. Maley, Damien Chevallier, Tuul Sepp, Thomas Pradeu, Mathieu Giraudeau

Presidential Fellows Articles and Research

Contrary to expectations based on their higher cell numbers, larger and longer-lived species do not face dramatically increased risk of cancer. This strongly suggests that evolution has fashioned natural cancer resistance mechanisms, yet our knowledge remains limited on what these mechanisms might be. The cancer immunological surveillance hypothesis, proposed by Burnet and Thomas in the 1950s, highlights immunity as a key factor determining species-specific cancer resistance. Here we address the original, evolutionary interpretation of this hypothesis by investigating the relationship between cancer mortality risk and markers of efficient antigen presentation. Our results show that the expansion of the MHC class …

Both Studying And Protecting Octopuses “On Their Own Terms”, Jennifer Jacquet, Janelle Kaz, Becca Franks, Christine Webb

Animal Sentience

Cephalopods – indeed, all animals – “must be seen on their own terms,” with respect for their autonomy and their ecological imperatives. This will provide greater scientific insight along with a more ethical and accurate understanding of minds beyond our own.

Cephalopod Consciousness On “Their Own Terms”: Who Are “They”?, Willa M. Lane, Victor Ajuwon, Nicola S. Clayton

Animal Sentience

Mather’s call to consider cephalopods’ consciousness “on their own terms” raises the question of the extent to which cephalopods can be considered a homogenous group. While coloeoid cephalopods share traits that strongly distinguish them from other molluscs and invertebrates, they show vast ecological and morphological diversity, with implications for the design of empirical investigations of consciousness. Extending Mather’s argument, we apply Birch et al.’s (2020) five-dimensional model to compare octopus, cuttlefish, squid, and nautilus. This comparison shows that even within a graded rather than categorical framework, putative consciousness profiles depend on which taxa are included in discussions of “cephalopod consciousness.” …

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 …

Phylogenetic Comparative Vocal Evolution, Casper W. Buchanan

Master's Theses

Vocal learning is a trait unique to humans, bats, cetaceans, primates, and birds (Jarvis & Nottebohm, 1997; McComb & Semple, 2005; Wilbrecht & Nottebohm, 2003). Although there has been extensive research on vocal learning in songbirds, parrots are an even closer proxy to human learning, as they are social, intelligent, and lifelong learners, with some having repertoires of over 300 sounds (Benedict et al., 2022; Péron et al., 2011; Thomsen et al., 2019; Toft & Wright, 2015). Elevated vocal learning can be attributed to the need for parrots to have strong communication skills through the sharing of information over foraging, …

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 …

Using Rattlesnake Venom To Model Complex Trait Evolution Across Ecological And Evolutionary Scales, Samuel R. Hirst

USF Tampa Graduate Theses and Dissertations

A central challenge in evolutionary biology is understanding how genetic variation leads to phenotypicdiversity, particularly for complex traits that strongly influence fitness. Traits form the substrate of natural selection, but it is genes, that are inherited across generations. To fully understand the evolutionary process, we must therefore connect the molecular basis of trait variation with the evolutionary outcomes of such traits.

For relatively simple traits, the genotype–phenotype relationship is well understood. Classic systems, such as coat color in beach mice or toxin resistance in garter snakes, have provided effective examples of how relatively few loci underlie conspicuous adaptive differences across …

The Term Consciousness And Impressive Evidence For Cephalopod Awareness, Donald M. Broom

Animal Sentience

Mather presents comprehensive evidence of cephalopod cognitive ability and of a high level of awareness. The importance of taking account of the biological functioning and adaptations to the living environment is emphasised. An argument is presented that it is better to limit the use of the word conscious to ‘not unconscious’ and to use awareness in relation to the various levels of cognitive functioning.

The Consciousness Inherent In Chasing Your Tail, Sergio M. Pellis Dr.

Animal Sentience

Who is conscious and how do we know? Complexity in behavior and cognition is certainly a clue that cannot be ignored in identifying this trait, and as Mather’s target article shows, it is hard not to imagine consciousness arising in cephalopods. But how complex is complex? An alternative may be gleaned from the fact that all living things rely on negative feedback to navigate their worlds, and this requires all sentient beings knowing what is to be stabilized in reflection to themselves. If so, consciousness is a universal trait.

Mhc Gene Analysis And Immune Variation In Lepidodactylus Lugubris (The Mourning Gecko), Helen T. Vu

2025 Fall Honors Capstones Projects - Archive

The major histocompatibility complex (MHC) plays a central role in vertebrate immune defense by enabling pathogen recognition and initiating adaptive immune responses. While MHC diversity has been extensively studied in sexually reproducing species, comparatively little is known about its evolution in asexual lineages. The parthenogenetic gecko Lepidodactylus lugubris provides a unique opportunity to investigate how clonality and hybrid origins influence immune gene diversity. By leveraging whole-genome data, this study overcomes the limitations of previous transcriptome-based analyses and provides a more comprehensive view of MHC diversity in a clonal vertebrate. As the first step towards understanding MHC evolution in parthenogenetic lizards, …

Cephalopod Consciousness: Asking The Right Questions, Gordon Burghardt

Animal Sentience

Jennifer Mather has provided a comprehensive and fascinating overview of the various cognitive accomplishments of cephalopods and their sensory, behavioral, and neurophysiological attributes. The advances in our understanding of a clade that has been separated from vertebrate evolution by well over half a billion years is a testament to advances in both methodology and the questions we now feel free to address. Mather embeds her review in the issue of consciousness, which is certainly a perennial issue in mental evolution, going back to Romanes and earlier. I argue that the term “consciousness” has such a checkered history and is used …

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 …

Dental Microwear And Diets Of Late Miocene Primates From Rudabánya, Hungary, Peter S. Ungar, Anna K. Wilcox, David R. Begun

School of Dentistry Faculty Publications

Objectives: This study focuses on a dental microwear texture analysis of European pliopithecids and dryopithecins from the Miocene primate site of Rudabánya, Hungary. The goal is to determine whether these taxa, found in part together in the same deposits, differed in their food preferences, or at least consumed, on a daily basis, in a manner that might have facilitated sympatry. Materials and Methods: Here we report on a molar surface texture analysis of all available fossil primates from Rudabánya that preserve antemortem microwear. This includes both Anapithecus hernyaki (n = 14) and Rudapithecus hungaricus (n = 5, including one from …

Two New Species Of Uroplectes Peters, 1861 (Scorpiones, Buthidae) From Somaliland And Mozambique, František Kovařík

Euscorpius

Two new species, Uroplectes elmii sp. n. from Somaliland and U. mossambicensis sp. n. from Mozambique are described, fully illustrated with color photos showing their morphology. Both species are similar to Uroplectes fischeri (Karsch, 1879) from which they differ mainly in finger dentition (Uroplectes elmii sp. n.) and strongly reduced tibial spurs on legs III–IV (U. mossambicensis sp. n.). Uroplectes elmii sp. n. is also compared with U. pardii Kovařík, 2003, from which it differs mainly by extremely reduced to absent metasomal punctation. A distribution map of all …

Alpiscorpius Huyukensis Sp. N., An Unexpected New Species From Sultan Mountains, Konya Province, Turkey (Scorpiones: Euscorpiidae), Ersen A. Yağmur, Halil İ. Yaylı

Euscorpius

A new scorpion species, Alpiscorpius huyukensis sp. n., is described from the western foothills of the Sultan Mountains, Konya Province, in the Aegean Region of western Turkey, based on morphological characters. The species is assigned to the genus Alpiscorpius Gantenbein et al., 1999, due to the presence of three trichobothria in the em series on the external surface of the pedipalp patella. A. huyukensis sp. n. can be readily distinguished from its all congeners by its yellowish-orange or greyish-orange body and yellow metasomal coloration, the fifth metasomal segment bearing distinct ventrolateral carinae, the presence of six trichobothria in the …

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 …

The Genus Androctonus Ehrenberg, 1828 (Scorpiones: Buthidae) In Oman, Graeme Lowe

Euscorpius

The taxonomic position of Androctonus populations in Oman was investigated by analyzing morphological variation in a comprehensive sample representing 150 records gathered from 95 localities spread throughout the country. Two new allopatric species are described, separated by multivariate morphometric analysis and meristic characters: (1) A. omanensis sp. n., distributed across most of Oman, is characterized by wider, deeper metasomal segments IV–V, shorter legs, more robust pedipalps, more granules on lateral inframedian carinae of metasoma II–III, and sparser setation on basitarsal spurs; and (2) A. ammophilus sp. n., distributed in the dunes of the Rub’ al-Khali (Empty Quarter) of …

Predation Of Aegaeobuthus Nigrocinctus (Ehrenberg, 1828) (Scorpiones: Buthidae) By A Middle East Black Tarantula, Chaetopelma Olivaceum (C. L. Koch, 1841) (Araneae: Theraphosidae) In Lebanon, Rami Khashab

Euscorpius

I report the first documented case of the buthid scorpion Aegaeobuthus nigrocinctus (Ehrenberg, 1828) serving as prey for the tarantula Chaetopelma olivaceum (C. L. Koch, 1841) in Lebanon. The observation was made during a nocturnal survey in the Mount Lebanon region. The case contributes to the limited records of tarantula predation on scorpions and underscores the role of prey-predator size asymmetry in facilitating high-risk predation among arachnids.

The Evolution And Reproduction Of Andean Miconia (Melastomataceae), Juan Angulo

Dissertations, Theses, and Capstone Projects

Understanding the factors that shape diversification and distribution in tropical plant lineages is central to explaining the origins of Neotropical biodiversity. Assessing evolutionary history with trait evolution and climatic niche dynamics provides key insights into the drivers of diversification and biogeography, while natural history data remains critical for these evolutionary studies. The Tropical Andes, with its exceptional biodiversity and environmental heterogeneity, offers an ideal setting to explore these processes. In this dissertation, I investigate how reproductive systems, climatic niche dynamics, and pollination strategies influence the evolution and biogeography of Miconia III, a large and ecologically diverse clade in the …

Systematics, Biogeography, And Comparative Morphology Of Emerald And Tigertail Dragonflies (Anisoptera: Synthemistidae & Corduliidae), Aaron M. Goodman

Dissertations, Theses, and Capstone Projects

Dragonflies and damselflies (Odonata Fabricius, 1793) are among the most widely recognized and charismatic insect groups, whose significance have permeated throughout artwork, culture, and religion. They are highly mobile predators, currently consisting of ~ 6,500 species, and possessing some of the complex visual color systems, visual acuity, and flight patterns on Earth. Odonata are the among the earliest flying insects, with proto-odonates (Griffinflies) dating back to the Carboniferous (~360mya), with crown-odonata fossils stretching back to the Triassic (~250mya). Overall, dragonflies and damselflies are considered models of ecological and evolutionary research due to their long evolutionary history, range of habitats, and …