Life Sciences Commons^™

Virulence Of Photorhabdus Spp.: Examining The Roles Of Environment, Evolution, And Genetics In Insect Mortality, Dana Blackburn

Theses and Dissertations

Entomopathogenic nematodes (EPNs) (genera Heterorhabditis and Steinernema) kill their invertebrate hosts with the aid of a mutualistic bacterium. The bacteria (Xenorhabdus spp. for steinernematids and Photorhabdus spp. for heterorhabditids) are primarily responsible for killing the host and providing the nematodes with nutrition and defense against secondary invaders. Photorhabdus is a Gram-negative bacterium in the Enterobacteriaceae family with high virulence towards their insect hosts. To achieve high mortality rates Photorhabdus produces a variety of virulence factors such as toxins, lipases, proteases, secretion systems, and fimbriae. EPNs are amenable to laboratory rearing and mass production for biocontrol applications against insects …

Genetic And Morphological Diversity Along Altitudinal Gradients In The Genus Rhoadsia (Teleostei: Characidae: Rhoadsiinae), Grace Malato

College of Science and Health Theses and Dissertations

The Neotropics have the highest fish species diversity of any area in the world, with some experts estimating that as many as 4000 species of fishes are present in freshwater ecosystems. Elevational gradients are partially responsible for this diversity due to the rapidly changing ecological conditions associated with changes in altitude in rivers. One area where elevational gradients are particularly important is Western Ecuador; this region forms part of a biodiversity hotspot extending south from Panama along the western side of the Andes. Fish species diversity is relatively low because of the small size of most of the river drainages …

The Incredible Shrinking Dewlap: Signal Size, Skin Elasticity, And Mechanical Design In The Green Anole Lizard (Anolis Carolinensis), Simon Lailvaux, Jack Leifer, Bonnie Kircher, Michele Johnson

Michele A Johnson

The expression of male secondary sexual traits can be dynamic, changing size, shape, color, or structure over the course of different seasons. However, the factors underlying such changes are poorly understood. In male Anolis carolinensis lizards, a morphological secondary sexual signal called the dewlap changes size seasonally within individuals. Here, we test the hypothesis that seasonal changes in male dewlap size are driven by increased use and extension of the dewlap in spring and summer, when males are breeding, relative to the winter and fall. We captured male green anole lizards prior to the onset of breeding and constrained the …

The Incredible Shrinking Dewlap: Signal Size, Skin Elasticity, And Mechanical Design In The Green Anole Lizard (Anolis Carolinensis), Simon Lailvaux, Jack Leifer, Bonnie Kircher, Michele Johnson

Jack Leifer

The expression of male secondary sexual traits can be dynamic, changing size, shape, color, or structure over the course of different seasons. However, the factors underlying such changes are poorly understood. In male Anolis carolinensis lizards, a morphological secondary sexual signal called the dewlap changes size seasonally within individuals. Here, we test the hypothesis that seasonal changes in male dewlap size are driven by increased use and extension of the dewlap in spring and summer, when males are breeding, relative to the winter and fall. We captured male green anole lizards prior to the onset of breeding and constrained the …

Intramolecular Phenotypic Capacitance In A Modular Rna Molecule, Eric J. Hayden, Devin P. Bendixsen, Andreas Wagner

Biology Faculty Publications and Presentations

Phenotypic capacitance refers to the ability of a genome to accumulate mutations that are conditionally hidden and only reveal phenotype-altering effects after certain environmental or genetic changes. Capacitance has important implications for the evolution of novel forms and functions, but experimentally studied mechanisms behind capacitance are mostly limited to complex, multicomponent systems often involving several interacting protein molecules. Here we demonstrate phenotypic capacitance within a much simpler system, an individual RNA molecule with catalytic activity (ribozyme). This naturally occurring RNA molecule has a modular structure, where a scaffold module acts as an intramolecular chaperone that facilitates folding of a second …

Evolution Practice 2, Imsa Biology Team

Evolution

Evolution Problems

Genetic Drift Simulation, Imsa Biology Team

Evolution

Genetic drift can be defined as a random fluctuation in gene frequency. More specifically, it tells us that different alleles may increase or decrease in a population in proportion to one another over time, just by chance, rather than due to any fitness advantage.

Mechanisms And Speciation 2: Evolution On The Web Questions, Imsa Biology Team

Evolution

The website below, sponsored by UC Berkeley, is a reliable source for information about evolution. This will give you the introductory information about the mechanisms of Evolution.

Mechanisms And Speciation 1: The Modern Synthesis, Imsa Biology Team

Evolution

The Modern Synthesis or Synthetic Theory of Evolution is an explanation of evolution that is based on modern genetic principles. According to the Modern Synthesis (a.k.a. Neo-Darwinism):

Evidence Of Evolution 2: Definitions For Evolutionary Evidence Lab, Imsa Biology Team

Evolution

This lab activity was designed to provide you with opportunities to make inferences and draw conclusions about evolution and the common ancestry of various animals based on their anatomical characteristics and comparative anatomy. You will be given tasks to accomplish or questions to answer at each of 11 stations. In order to do this successfully, you must make careful observations of the specimens on display. You must also know the following definitions before beginning this activity:

Evolution Practice 1, Imsa Biology Team

Evolution

Answer the following questions using information from the handouts, and examples from the LAB

Evidence Of Evolution 1: Structures, Imsa Biology Team

Evolution

In order to investigate linage, evolutionary history, and common ancestry, you need to be familiar with the following structures.

Essential Questions, Imsa Biology Team

Evolution

In order to understand the current state of biological life and how it has changed over time, the following questions must be addressed:

Evidence Of Evolution 3: Evolutionary Evidence And Inferences Lab: A Discussion Guide, Imsa Biology Team

Evolution

This lab activity was designed to provide you with opportunities to make inferences and draw conclusions about evolution and the common ancestry of various animals based on their anatomical characteristics and comparative anatomy. You will be given tasks to accomplish or questions to answer at each of 11 stations. In order to do this successfully, you must make careful observations of the specimens on display.

The Incredible Shrinking Dewlap: Signal Size, Skin Elasticity, And Mechanical Design In The Green Anole Lizard (Anolis Carolinensis), Simon P. Lailvaux, Jack Leifer, Bonnie K. Kircher, Michele A. Johnson

Biology Faculty Research

The expression of male secondary sexual traits can be dynamic, changing size, shape, color, or structure over the course of different seasons. However, the factors underlying such changes are poorly understood. In male Anolis carolinensis lizards, a morphological secondary sexual signal called the dewlap changes size seasonally within individuals. Here, we test the hypothesis that seasonal changes in male dewlap size are driven by increased use and extension of the dewlap in spring and summer, when males are breeding, relative to the winter and fall. We captured male green anole lizards prior to the onset of breeding and constrained the …

Peripheral And Central Mechanisms Of Temporal Pattern Recognition, Christa Ann Baker

Arts & Sciences Electronic Theses and Dissertations

Encoding information into the timing patterns of action potentials, or spikes, is a strategy used broadly in neural circuits. This type of coding scheme requires downstream neurons to be sensitive to the temporal patterns of presynaptic inputs. Indeed, neurons with temporal filtering properties have been found in a wide range of sensory pathways. However, how such response properties arise was previously not well understood. The goal of my dissertation research has been to elucidate how temporal filtering by single neurons contributes to the behavioral ability to recognize timing patterns in communication signals.

I have addressed this question using mormyrid weakly …

Evolutionary Developmental Leaf Morphology Of The Plant Family Araceae, Claudia Liliana Henriquez

Arts & Sciences Electronic Theses and Dissertations

Studying the evolutionary developmental morphology of leaves using next-generation phylogenetics, a candidate gene approach and comparative developmental studies in the plant family Araceae is the overarching theme of the dissertation.

The plant family Araceae is an ancient lineage from the Early Cretaceous and belongs to the monocotyledons. Members of Araceae display striking variation in leaf development; such variation contradicts traditional models of monocot leaf development. Additionally, dissected leaves, which are rare in monocots, seem to have evolved independently multiple times in Araceae by various developmental mechanisms.

Despite extensive efforts to elucidate the evolutionary history of Araceae, phylogenetic ambiguity in the …

The Sea Lamprey Meiotic Map Improves Resolution Of Ancient Vertebrate Genome Duplications, Jeramiah James Smith, Melissa C. Keinath

Biology Faculty Publications

It is generally accepted that many genes present in vertebrate genomes owe their origin to two whole-genome duplications that occurred deep in the ancestry of the vertebrate lineage. However, details regarding the timing and outcome of these duplications are not well resolved. We present high-density meiotic and comparative genomic maps for the sea lamprey (Petromyzon marinus), a representative of an ancient lineage that diverged from all other vertebrates ~550 million years ago. Linkage analyses yielded a total of 95 linkage groups, similar to the estimated number of germline chromosomes (1n ~ 99), spanning a total of 5570.25 cM. …

Origin And Evolution Of Petrocosmea (Gesneriaceae) Inferred From Both Dna Sequence And Novel Findings In Morphology With A Test Of Morphology-Based Hypotheses, Zhi-Jing Qiu, Yuan-Xue Lu, Chao-Qun Li, Yang Dong, James F. Smith, Yin-Zheng Wang

Biology Faculty Publications and Presentations

Background: Petrocosmea Oliver (Gesneriaceae) currently comprises 38 species with four non-nominate varieties, nearly all of which have been described solely from herbarium specimens. However, the dried specimens have obscured the full range of extremely diverse morphological variation that exists in the genus and has resulted in a poor subgeneric classification system that does not reflect the evolutionary history of this group. It is important to develop innovative methods to find new morphological traits and reexamine and reevaluate the traditionally used morphological data based on new hypothesis. In addition, Petrocosmea is a mid-sized genus but exhibits extreme diverse floral variants. This …

Climate-Driven Change In Himalayan Rhododendron Phenology, Robert Evan Hart

Dissertations

Phenology – the seasonal timing of life-history events – is a critical dimension of natural history. It is also one of the earliest and most noticeable traits by which organisms respond to climate change. However, these responses are complex, and only beginning to be understood, especially in the montane and alpine environments that are among the ecosystems most vulnerable to climate change. Drawing from diverse data sets and employing multiple methodologies, I examined how climate affects phenology in Himalayan Rhododendron spp. Comprehensively monitoring flowering phenology over gradients of season and elevation on Mt. Yulong, China – home to a diverse …

The U1a/U2b"/Snf Family Of Rna Binding Proteins: Evolution Of Rna Binding Specificity And Contributions Of Heterotropic Linkage To Snrnp Protein Partitioning, Sandra Gisela Williams

Arts & Sciences Electronic Theses and Dissertations

The U1A/U2B"/SNF is a family of RNA binding proteins that is a highly conserved throughout eukaryotes. These proteins are found in the U1 and/or U2 splicing snRNPs (small nuclear ribonucleoprotein particles). In humans, U1A and U2B" specifically bind to the U1 and U2 snRNAs, respectively. The Drosophila genome codes for SNF, an essential protein that localizes to both the U1 and U2 snRNP. While a specific splicing functions for these proteins have not been determined, their conserved snRNP localization suggests an important splicing-related function.

The difference in protein number and partitioning between Drosophila and humans suggested that these proteins may …

Hayek Deserves A New Paradigm, Not Old Ideological Categories: Response To Searles, David S. Wilson, Robert Kadar, Steve Roth

Biological Sciences Faculty Scholarship

Like Harrison Searles, we’re confident that modern evolutionary science provides a useful toolkit for economics and public policy. Some progress has been made advancing a new paradigm. Searles rightfully calls attention to the pioneering work of Friedrich Hayek. We are in a much better position to approach these topics now than during Hayek’s time. We think that modern multilevel selection theory and complexity theory lead to conclusions different than those that Searles and others draw from Hayek’s work. But we suggest dropping terms such as “evolutionary left” as a first step toward acknowledging that new paradigms cannot be shoehorned into …

Restriction Site-Associated Dna Sequencing (Rad-Seq) Reveals An Extraordinary Number Of Transitions Among Gecko Sex-Determining Systems, Tony Gamble, Jessi Coryell, Tariq Ezaz, Joshua Lynch

Biological Sciences Faculty Research and Publications

Sex chromosomes have evolved many times in animals and studying these replicate evolutionary “experiments” can help broaden our understanding of the general forces driving the origin and evolution of sex chromosomes. However this plan of study has been hindered by the inability to identify the sex chromosome systems in the large number of species with cryptic, homomorphic sex chromosomes. Restriction site-associated DNA sequencing (RAD-seq) is a critical enabling technology that can identify the sex chromosome systems in many species where traditional cytogenetic methods have failed. Using newly generated RAD-seq data from 12 gecko species, along with data from the literature, …

Some Agreement On Kin Selection And Eusociality?, David C. Queller, Stephen Rong, Xiaoyun Liao

Biology Faculty Publications & Presentations

The authors of "Relatedness, Conflict, and the Evolution of Eusociality" respond to objections raised by Martin Nowak and Benjamin Allen.

Evolution And Biodiversity, Timothy Henkel, Emily Croteau, Matthew Waters

Biological Sciences Grants Collections

This Grants Collection for Evolution and Biodiversity was created under a Round Four ALG Textbook Transformation Grant.

Affordable Learning Georgia Grants Collections are intended to provide faculty with the frameworks to quickly implement or revise the same materials as a Textbook Transformation Grants team, along with the aims and lessons learned from project teams during the implementation process.

Documents are in .pdf format, with a separate .docx (Word) version available for download. Each collection contains the following materials:

• Linked Syllabus
• Initial Proposal
• Final Report

Whole Genome Comparison Of A Large Collection Of Mycobacteriophages Reveals A Continuum Of Phage Genetic Diversity, Welkin Pope, Charles Bowman, Daniel Russell, Deborah Jacobs-Sera, David Asai, Steven Cresawn, William Jacobs, Roger Hendrix, Jeffrey Lawrence, Graham Hatfull, Sarah C.R. Elgin

Biology Faculty Publications & Presentations

The bacteriophage population is large, dynamic, ancient, and genetically diverse. Limited genomic information shows that phage genomes are mosaic, and the genetic architecture of phage populations remains ill-defined. To understand the population structure of phages infecting a single host strain, we isolated, sequenced, and compared 627 phages of Mycobacterium smegmatis. Their genetic diversity is considerable, and there are 28 distinct genomic types (clusters) with related nucleotide sequences. However, amino acid sequence comparisons show pervasive genomic mosaicism, and quantification of inter-cluster and intra-cluster relatedness reveals a continuum of genetic diversity, albeit with uneven representation of different phages. Furthermore, rarefaction analysis shows …

Relatedness, Conflict, And The Evolution Of Eusociality, Xiaoyun Liao, Stephen Rong, David C. Queller

Biology Faculty Publications & Presentations

The evolution of sterile worker castes in eusocial insects was a major problem in evolutionary theory until Hamilton developed a method called inclusive fitness. He used it to show that sterile castes could evolve via kin selection, in which a gene for altruistic sterility is favored when the altruism sufficiently benefits relatives carrying the gene. Inclusive fitness theory is well supported empirically and has been applied to many other areas, but a recent paper argued that the general method of inclusive fitness was wrong and advocated an alternative population genetic method. The claim of these authors was bolstered by a …

Addressing Misconceptions About Evolution, Sarah O'Leary-Driscoll, Don Dosch

Faculty Publications & Research

"Leave with effective ways to identify and address misconceptions about evolution, with a particular focus on supporting explanations with evidence."

Population Genomic Inference Of Ecology, Conservation, Evolution, And Demographic History Of Atlantic Seahorses And Pipefishes (Syngnathidae), Joel Thomas Boehm

Dissertations, Theses, and Capstone Projects

In the Atlantic Ocean powerful directional ocean currents can play a significant role in the formation and persistence of marine species. Syngnathidae fishes have a sparse fossil record, high morphological plasticity, and many of these species are difficult to observe in the wild, therefore they frequently lack life history information and the status of regional lineages and species designations are often obscure. In this dissertation I explore the ecology, evolution, and conservation of primarily Atlantic seahorses (Hippocampus) and pipefish (Syngnathus) in four core chapters, using differing genetic datasets ranging from mitochondrial DNA to genome-wide RAD sequences. Most Synganthids have the …

Systematics And Biogeography Of Orthaea Kloztsch (Ericaceae: Vaccinieae), Nelson Salinas

Dissertations, Theses, and Capstone Projects

In the first chapter a study of the distribution patterns of the neotropical Vaccinieae (Ericaceae) is presented. Five areas of endemism were recovered: Central America, northern Chocó, southern Chocó, eastern Ecuador, and Yungas. Divergence times estimations indicate that the Andean clade of Vaccinieae migrated to South America during the Late Oligocene or Early Miocene (28.9-17.84 MA), and most of the subsequent diversification took place during the Tertiary. The Yungas was the first Andean area to be colonized, and several dispersals towards the north expanded their distribution range. Both areas of endemism and dispersal events were influenced by geological processes, such …