Ecology and Evolutionary Biology Commons^™

Effects Of Riverine Barriers On Avian Evolution In The Amazon Basin, Andre Eugene Moncrieff

LSU Doctoral Dissertations

The high biodiversity found in the Amazon Basin has long captivated the attention of naturalists and evolutionary biologists seeking to explain its origins. Early observations by Alfred Wallace highlighted the role of rivers in delimiting the geographic ranges of many species; furthermore, where rivers narrow towards their headwaters, he noted that some species cross rivers freely. A major goal of this dissertation is to investigate how these and other observations about riverine barriers might inform our understanding of how speciation unfolds in Amazonia. My approach involved generating genomic data with dense geographic sampling for manakins in the genus Lepidothrix, …

Evolution Of Freshwater Fishes In The Northern Neotropics, Diego Elias

LSU Doctoral Dissertations

The northern Neotropics (NN) represents one of the most geologically-complex regions on the planet, composed of island-like geological blocks that have undergone multiple episodes of isolation and connectivity at various geological times. The riverscapes of the NN harbor a unique assemblage of freshwater fishes. In contrast to the freshwaters systems of South America, which are dominated by ostariophysan lineages, the aquatic systems of the NN are dominated by lineages of two families: Cichlidae (cichlids) and Poeciliidae (livebearers). It has been suggested that the geologically complex nature of the region allowed ancestors of cichlids and livebearers to colonize and radiate within …

Insights Into The Speciation Process From Genomic And Phenotypic Analysis Of An Avian Hybrid Zone In Amazonia, Glaucia Christina Del-Rio

LSU Doctoral Dissertations

Understanding the outcome of secondary contact is essential to shed light on the mechanisms governing species formation and maintenance. In Amazonia, closely related bird taxa with limited dispersal abilities are often separated by rivers, which presumably act as dispersal barriers. However, at the headwaters, rivers cease to be dispersal barriers, and this generates opportunities for secondary contact. In my dissertation, I studied genomic mechanisms associated with phenotypic differences, mitochondrial DNA structure, and putative reproductive barriers between two hybridizing Amazonian bird species in the genus Rhegmatorhina, a group of antbirds that find their arthropod prey exclusively by following army-ant swarms. …

Genetic Structuring And Community Assembly In Neotropical Birds, Oscar Johnson

LSU Doctoral Dissertations

The factors that influence how species form is of fundamental interest to biology. Under the framework of the speciation cycle, the process begins by population subdivision creating structured populations that then diverge until two new species form. Following speciation, however, continued divergence is necessary for these new species to be able to coexist without adverse interactions, known as the transition to secondary sympatry. At this point the speciation cycle is complete and the process can begin anew. Many of the factors influencing these processes remain poorly understood. Here, I explore the factors that influence speciation and community assembly in Neotropical …

Micro- And Macroevolution Of Drab Plumage Color In Birds, Rafael Marcondes

LSU Doctoral Dissertations

I address the evolution of drab bird colors at micro- and macroevolutionary scales. I use as a study system the Furnariida, a clade of >600 Neotropical passerine species that, despite tremendous ecological and morphological diversity, are colored almost exclusively in shades of brown and grey produced by melanin pigments.

In chapters two and three, I took a macroevolutionary approach and showed that (1) plumage colors in the Furnariida evolve at similar rates in a monochromatic clade, males of a dichromatic clade, and females of a dichromatic clade; (2) ventral plumage color evolves faster than dorsal; (3) bird species that occupy …

Quantifying Structure And Variation In Complex Phylogenetic Data, Genevieve Geraldine Mount

LSU Doctoral Dissertations

Identifying the source and structure of variation in nature is crucial to understanding fundamental aspects of evolution. Despite a recent plethora of genetic and morphological data, many interesting questions about the relationships between different groups remain unresolved. My dissertation evaluates three approaches for identifying and quantifying the variation within phylogenetic datasets. Characterizing variation within datasets and across analytical methods gives insight into biologically interesting characters, unusual evolutionary processes, and areas for model improvement.

Network-based community detection approaches offer a powerful tool to describe variation in phylogenetic signal across the genome (i.e., gene tree variation). In Chapter 2, I investigate the …

The Evolution Of Bivalve Shell Matrix Proteins, Mark Ira Duhon Ii

LSU Doctoral Dissertations

This dissertation focuses on the molecular underpinnings surrounding the evolution of the biomineralized shells of marine bivalves. Bivalve molluscs synthesize remarkably complex shells from calcium carbonate and an organic matrix of proteins secreted from the dorsal edge of the mantle. Molecular analyses of shell matrix proteins (SMPs) have suggested high rates of gene turnover despite the conserved nature of the shell itself. Here, I used proteomic and transcriptomic data to identify the SMPs and other biomineralization proteins from seven bivalve species that diverged 3-513 Mya. Contrary to previous studies that identified only a few shared biomineralization transcripts across the Bivalvia, …

Taxonomy And Systematics Of The New Zealand Pselaphini (Coleoptera: Staphylinidae: Pselaphinae), Brittany Elin Owens

LSU Doctoral Dissertations

The New Zealand (NZ) Pselaphini was revised at the species level, a phylogenetic analysis was performed using morphological data, and first steps were taken towards the construction of a molecular analysis of the tribe. Eight new genera and 33 new species were discovered from specimens collected from the NZ mainland, offshore islands, Chatham Islands and the Subantarctic Islands. Of the 13 species originally described in the genus Pselaphus by Thomas Broun during the late 19^th and early 20^th centuries, all were either reassigned to the genera Pselaphaulax and Pselaphogenius, or were placed into new genera. Three names …

Natural Variation And Evolutionary Responses To Climate Change Stressors In Marine Invertebrates, Joanna Sarah Griffiths

LSU Doctoral Dissertations

Our rapidly changing climate is putting many species at risk of extinction and there is an urgent need to understand how species will respond to these changes. In this dissertation, I evaluate how three species of marine invertebrates (corals, oysters, and copepods) respond to stressful conditions in their current environments and how plasticity and evolutionary adaptation could alter their response to future climate change stressors. I first employed a space for time study to elucidate population differences in the response of cold-water corals, Balanophyllia elegans, to future ocean acidification. I found evidence that upwelling history (natural low pH exposure) influences …

Phylogeny And Evolution Of Swallows (Hirundinidae) With A Transcriptomic Perspective On Seasonal Migration, Clare Elisabeth Brown

LSU Doctoral Dissertations

Evolutionary biology seeks to understand the forces that have generated and shaped patterns of diversity. In this dissertation, I investigated phylogenetic relationships and the evolution of three traits—migration, nest-type, and geographic distribution—in the swallow family (Hirundinidae), a globally distributed group of about 85 species of aerial insectivorous birds. I first applied a dataset of several thousand ultraconserved element (UCE) loci to reconstructing the phylogeny of the New World genus Tachycineta. Three methods of phylogenetic inference produced topologically discordant trees, but post-inference analyses provided evidence that the tree produced by maximum likelihood analysis of a concatenated data matrix is the most …

Determining The Drivers Of Anti-Tropical Distributions Across The Fish Tree Of Life, William Benton Ludt

LSU Doctoral Dissertations

Anti-tropical distributions are those where populations of a single species, or multiple closely related taxa, are distributed outside of, and on opposing sides of, the tropics. These latitudinally disjunct distributions have been noted for over a century. Despite this long history of interest, little has been concluded regarding the actual mechanisms that drive this pattern, with several prominent hypotheses competing with one another in the literature. Here I review the proposed drivers of anti-tropicality, and subsequently test them using fishes with a variety of life history and taxonomic differences. This includes (1) a temperately restricted family with anti-tropical distributions – …

Computational Analysis Of Papionini Evolution Using Alu Insertions, Vallmer Edward Jordan Ii

LSU Doctoral Dissertations

Alu elements are primate specific retrotransposons that have remained active throughout the course of primate evolution. As a result of this sustained mobilization. Alu elements are present in greater copy number in primate genomes than any other transposable element. An average of over one million Alu elements has been identified in every sequenced haplorrhine genome to date. These characteristics qualify Alu elements as ideal characters for studying evolutionary relationship among primates.

The increasing availability of whole genome sequencing data presents novel challenges and opportunities for comparative genomic analyses. Genomic data is now publicly available for most primate species. Such an …

Evolution Of Alu Elements In The Saimiri And Papio Lineages Of Primates, Jasmine Nicole Brown Baker

LSU Doctoral Dissertations

Alu elements are approximately 300 base pair (bp) primate specific non- autonomous retrotransposons. Alu elements, a short interspersed element (SINE), account for high copy numbers in all primate genomes. Numerous Alu element subfamilies have undergone varying degrees of activity and amplification within primates. Identification of these subfamilies has proved to be very informative in elucidating phylogenies and as phylogenomic markers. Squirrel monkeys, genus Saimiri, are one of the most well-known neotropical primates and the second most commonly used laboratory monkey. Squirrel monkey species diverged approximately 1.5 million years ago and are native to South America. Despite being well-known, there …

Evotext: A New Tool For Analyzing The Biological Sciences, Grant Ramsey, Charles H. Pence

Faculty Publications

We introduce here evoText, a new tool for automated analysis of the literature in the biological sciences. evoText contains a database of hundreds of thousands of journal articles and an array of analysis tools for generating quantitative data on the nature and history of life science, especially ecology and evolutionary biology. This article describes the features of evoText, presents a variety of examples of the kinds of analyses that evoText can run, and offers a brief tutorial describing how to use it.

Fitness: Philosophical Problems, Grant Ramsey, Charles H. Pence

Faculty Publications

Fitness plays many roles throughout evolutionary theory, from a measure of populations in the wild to a central element in abstract theoretical presentations of natural selection. It has thus been the subject of an extensive philosophical literature, which has primarily centred on the way to understand the relationship between fitness values and reproductive outcomes. If fitness is a probabilistic or statistical quantity, how is it to be defined in general theoretical contexts? How can it be measured? Can a single conceptual model for fitness be offered that applies to all biological cases, or must fitness measures be case-specific? Philosophers have …

Staffan Müller-Wille And Hans-Jörg Rheinberger, A Cultural History Of Heredity, Charles H. Pence

Faculty Publications

No abstract provided.

A Path To Success? A Review Of Evolution, Development, And The Predictable Genome By David L. Stern, Hope Hollocher, Charles H. Pence, Grant Ramsey, Michelle M. Wirth

Faculty Publications

No abstract provided.

On The Origin Of Stories: Evolution, Cognition, And Fiction, Hope Hollocher, Agustín Fuentes, Charles H. Pence, Grant Ramsey, Daniel John Sportiello, Michelle M. Wirth

Faculty Publications

No abstract provided.

Darwinian Populations And Natural Selection, Grant Ramsey, Hope Hollocher, Agustín Fuentes, Charles H. Pence, Edwin Siu

Faculty Publications

No abstract provided.