Biology Commons^™

Hearing On The Fly: The Effects Of Wing Position On Noctuid Moth Hearing, Shira D. Gordon, Elizabeth Klenschi, James F. C. Windmill

Dartmouth Scholarship

The ear of the noctuid moth has only two auditory neurons, A1 and A2, which function in detecting predatory bats. However, the noctuid's ears are located on the thorax behind the wings. Therefore, as these moths need to hear during flight, it was hypothesized that wing position may affect their hearing. The wing was fixed in three different positions: up, flat and down. An additional subset of animals was measured with freely moving wings. In order to negate any possible acoustic shadowing or diffractive effects, all wings were snipped, leaving the proximal-most portion and the wing hinge intact. Results revealed …

Mutations: Evolution's Disappointment, Georgia (Hickman) Purdom

Alumni Publications

No abstract provided.

Fundamental Theorems Of Evolution, David C. Queller

Biology Faculty Research

Evolutionary biology is undergirded by an extensive and impressive set of mathematical models. Yet only one result, Fisher’s theorem about selection and fitness, is generally accorded the status of a fundamental theorem. I argue that although its fundamental status is justified by its simplicity and scope, there are additional results that seem similarly fundamental. I suggest that the most fundamental theorem of evolution is the Price equation, both because of its simplicity and broad scope and because it can be used to derive four other familiar results that are similarly fundamental: Fisher’s average-excess equation, Robertson’s secondary theorem of natural selection, …

Sequential Displacement Of Type Vi Secretion System Effector Genes Leads To Evolution Of Diverse Immunity Gene Arrays In Vibrio Cholerae, Paul C. Kirchberger, Daniel Unterweger, Daniele Provenzano, Stefan Pukatzki, Yan Boucher

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Type VI secretion systems (T6SS) enable bacteria to engage neighboring cells in contact-dependent competition. In Vibrio cholerae, three chromosomal clusters each encode a pair of effector and immunity genes downstream of those encoding the T6SS structural machinery for effector delivery. Different combinations of effector-immunity proteins lead to competition between strains of V. cholerae, which are thought to be protected only from the toxicity of their own effectors. Screening of all publically available V. cholerae genomes showed that numerous strains possess long arrays of orphan immunity genes encoded in the 3' region of their T6SS clusters. Phylogenetic analysis reveals that these …

A Model Of The Use Of Evolutionary Trees (Muet) To Inform K-14 Biology Education, Yi Kong, Ankita Thawani, Trevor R. Anderson, Nancy Pelaez

PIBERG Publications

Evolutionary trees are powerful tools used in modern biological research, and also commonly used in textbooks and classroom instruction. Studies have shown that K-14 students have difficulties interpreting evolutionary trees. To improve student learning about this topic, it is essential to teach them how to understand and use trees like professional biologists. Unfortunately, few currently used teaching frameworks for evolution instruction are designed for this purpose. In this study we developed the Model of the Use of Evolutionary Trees (MUET), a conceptual model that characterizes how evolutionary trees were used by professional biologists as represented in their research publications. The …

Primate Proteomic Composition Of Seminal Plasma And Prostate-Specific Transglutaminase Activity In Relation To Sexual Selection., Amanda M.C. Zielen

Electronic Theses and Dissertations

Humans (Homo sapiens), chimpanzees (Pan troglodytes), and gorillas (Gorilla gorilla) have diverse mating systems with varying levels of sperm competition. Several seminal plasma genes have been claimed to evolve under positive selection, while others are altered or lost. This study aims to identify biologically relevant differences among seminal plasma proteomes of primates in relation to mating systems and previous genomic studies. Seminal plasma from three individuals of each species were run in triplicate in shotgun liquid chromatography – tandem mass spectrometry (LC-MS/MS) and confirmed with Western blots. Over 7,000 peptides were identified across all …

Evolutionary Linkage Of Mimetic And Non-Mimetic Color Traits In A Coral Snake Mimicry Complex, John D. Curlis Jr

College of Graduate Studies: Theses & Dissertations

Color polymorphism in aposematic mimicry systems is a perplexing phenomenon for evolutionary biologists, as theoretically the benefits of converging on a model phenotype should constrain the evolution of phenotypic diversity in these systems (i.e., color polymorphism should not occur). Nevertheless, color polymorphism in mimicry systems is prevalent throughout many taxa. In some of these systems, the evolution of color polymorphism results in the existence of non-mimetic morphs, such as those that are cryptic. The case of ground snakes (Sonora semiannulata) is unique in that color polymorphism encompasses both mimetic and cryptic morphs, as well as individual mimetic and …

Crassulacean Acid Metabolism As A Continuous Trait: Variability In The Contribution Of Crassulacean Acid Metabolism (Cam) In Populations Of Portulacaria Afra, Lonnie J. Guralnick, Kate Gladsky

Arts & Sciences Faculty Publications

Portulacaria afra L. is a dominant facultative CAM species growing in the Southeastern Cape of South Africa. P. afra is well adapted to regions of the Spekboom thicket in areas of limited and sporadic rainfall. P. afra populations occur in isolated drainages. We hypothesized the utilization of CAM would vary in the different populations in response to rainfall and temperature gradients. Carbon isotope composition can be used to determine the contribution of CAM in leaf tissue. P. afra leaves of populations were analyzed in transects running south to north and east to west in locations from the coast to elevations …

Evolution In The Deep Sea: Scales And Mechanisms Of Population Divergence, Amanda E. Glazier

Graduate Doctoral Dissertations

The deep sea is the Earth’s largest ecosystem and harbors a unique and largely endemic fauna. Although most research has focused on the ecological mechanisms that allow coexistence, recent studies have begun to investigate how this remarkable fauna evolved.. My work quantifies geographic patterns of genetic variation and investigates potential mechanisms that shape evolution in the deep ocean.

Bathymetric genetic divergence is common in the deep sea with population structure typically decreasing with depth. The evolutionary mechanisms that underlie these patterns are poorly understood. Geographic patterns of genetic variation indicated that the protobranch bivalve Neilonella salicensis was composed of two …

Origins And Maintenance Of Diversity In A Vertebrate Parthenogen, Alex Scott Hall

Biology Dissertations - Archive

Clonal lineages are expected to experience a decline in fitness over time due to their inability to decouple deleterious and beneficial alleles. Individually, however, asexual populations pass twice as much of their DNA per generation as sexual lineages. This balancing act between Muller's Ratchet and the lack of the two-fold cost of sex in asexuals brings significant scientific intrigue to instances of asexual populations. Among vertebrates, squamates (and mainly lizards) are uniquely capable of true parthenogenesis whereby females reproduce without males. These lineages are always hybrid, as is the case with parthenogenetic Aspidoscelis lizards (Teiidae). In particular, the checkered whiptail …

The Urea Carboxylase And Allophanate Hydrolase Activities Of Urea Amidolyase Are Functionally Independent, Yi Lin, Cody J. Boese, Martin St. Maurice

Biological Sciences Faculty Research and Publications

Urea amidolyase (UAL) is a multifunctional biotin-dependent enzyme that contributes to both bacterial and fungal pathogenicity by catalyzing the ATP-dependent cleavage of urea into ammonia and CO₂. UAL is comprised of two enzymatic components: urea carboxylase (UC) and allophanate hydrolase (AH). These enzyme activities are encoded on separate but proximally related genes in prokaryotes while, in most fungi, they are encoded by a single gene that produces a fusion enzyme on a single polypeptide chain. It is unclear whether the UC and AH activities are connected through substrate channeling or other forms of direct communication. Here, we use …

How Could Consciousness Emerge From Adaptive Functioning?, Max Velmans

Animal Sentience

The sudden appearance of consciousness that Reber posits in creatures with flexible cell walls and motility rather than non-flexible cells walls and no motility involves an evolutionary discontinuity. This kind of “miracle” is required by all “discontinuity” theories of consciousness. To avoid miraculous emergence, one may need to consider continuity theories, which accept that different forms of consciousness and material functioning co-evolve but assume the existence of consciousness to be primal in the way that matter and energy are assumed to be primal in physics.

Systematics And Evolution Of The Arundinoideae And Micrairoideae (Poaceae), Jordan Kinsley Teisher

Arts & Sciences Graduate Student Theses and Dissertations

The grass family, Poaceae, is one of the most ecologically and economically important plant groups on Earth. However, the large size (over 11,000 species) and geographic range of the family makes complete resolution of the evolutionary relationships in Poaceae challenging, with some significant groups remaining neglected. Two such understudied clades, subfamilies Arundinoideae and Micrairoideae, possess an incredible amount of morphological and ecological diversity for their sizes, making them a potentially rewarding system in which to study evolution of a wide range of grass features. In this dissertation, I resolved many of the long-standing systematic issues in Arundinoideae and Micrairoideae and …

Phylogenetic Relationships And Evolution Of Snakes, Alex Figueroa

LSU New Orleans Theses and Dissertations

Snakes represent an impressive evolutionary radiation of over 3,500 widely-distributed species, categorized into 515 genera, encompassing a diverse range of morphologies and ecologies. This diversity is likely attributable to their distinctive morphology, which has allowed them to populate a wide range of habitat types within most major ecosystems. In my first chapter, I provide the largest-yet estimate of the snake tree of life using maximum likelihood on a supermatrix of 1745 taxa (1652 snake species + 7 outgroup taxa) and 9,523 base pairs from 10 loci (5 nuclear, 5 mitochondrial), including previously unsequenced genera (2) and species (61). I then …

Home-Field Advantage? Evidence Of Local Adaptation Among Plants, Soil, And Arbuscular Mycorrhizal Fungi Through Meta-Analysis, Megan A. Rúa, Anita Antoninka, Pedro M. Antunes, V Bala Chaudhary, Catherine Gehring, Louis J. Lamit, Bridget J. Piculell, James D. Bever, Cathy Zabinski, James F. Meadow, Marc J. Lajeunesse, Brook G. Milligan, Justine Karst, Jason D. Hoeksema

Integrative Biology Faculty and Staff Publications

BACKGROUND: Local adaptation, the differential success of genotypes in their native versus foreign environment, arises from various evolutionary processes, but the importance of concurrent abiotic and biotic factors as drivers of local adaptation has only recently been investigated. Local adaptation to biotic interactions may be particularly important for plants, as they associate with microbial symbionts that can significantly affect their fitness and may enable rapid evolution. The arbuscular mycorrhizal (AM) symbiosis is ideal for investigations of local adaptation because it is globally widespread among most plant taxa and can significantly affect plant growth and fitness. Using meta-analysis on 1170 studies …

Life In The Underworld: Anchialine Cave Biology In The Era Of Speleogenomics, Jorge L. Pérez-Moreno, Thomas M. Iliffe, Heather D. Bracken-Grissom

International Journal of Speleology

Anchialine caves contain haline bodies of water with underground connections to the ocean and limited exposure to open air. Despite being found on islands and peninsular coastlines around the world, the isolation of anchialine systems has facilitated the evolution of high levels of endemism among their inhabitants. The unique characteristics of anchialine caves and of their predominantly crustacean biodiversity nominate them as particularly interesting study subjects for evolutionary biology. However, there is presently a distinct scarcity of modern molecular methods being employed in the study of anchialine cave ecosystems. The use of current and emerging molecular techniques, e.g., next-generation sequencing …

Colwellia Psychrerythraea Strains From Distant Deep Sea Basins Show Adaptation To Local Conditions, Stephen Techtmann, Kathleen S. Fitgerald, Savannah C. Stelling, Dominique C. Joyner, Sagar M. Uttukar, Austin P. Harris, Et Al.

Michigan Tech Publications, Part 1

Many studies have shown that microbes, which share nearly identical 16S rRNA genes, can have highly divergent genomes. Microbes from distinct parts of the ocean also exhibit biogeographic patterning. Here we seek to better understand how certain microbes from the same species have adapted for growth under local conditions. The phenotypic and genomic heterogeneity of three strains of Colwellia psychrerythraea was investigated in order to understand adaptions to local environments. Colwellia are psychrophilic heterotrophic marine bacteria ubiquitous in cold marine ecosystems. We have recently isolated two Colwellia strains: ND2E from the Eastern Mediterranean and GAB14E from the Great Australian Bight. …

Nocturnal Foraging Enhanced By Enlarged Secondary Eyes In A Net-Casting Spider, Jay A. Stafstrom, Eileen A. Hebets

Eileen Hebets Publications

Animals that possess extreme sensory structures are predicted to have a related extreme behavioral function. This study focuses on one such extreme sensory structure—the posterior median eyes of the net-casting spider Deinopis spinosa. Although past research has implicated the importance of vision in the nocturnal foraging habits of Deinopis, no direct link between vision in the enlarged eyes and nocturnal foraging has yet been made. To directly test the hypothesis that the enlarged posterior median eyes facilitate visually based nocturnal prey capture, we conducted repeated-measures, visual occlusion trials in both natural and laboratory settings. Our results indicate that D. …

The Influence Of Spines On Predation And Survivorship Of Devonian Brachiopods, Broc S. Kokesh

Undergraduate Research Symposium 2016

Brachiopods are small animals that live on the seafloor and are abundant in the Devonian fossil record (420 to 360 million years ago), making them excellent subjects for studying evolution in ancient marine environments. Some species sported large spines that cover their exterior surfaces, although these spines are typically broken off during fossilization. Paleontologists have hypothesized that these spines developed as an evolutionary response to predation, yet few studies have tested this idea due to the scarcity of specimens with intact spines. Recent work has been able to get around this problem by examining injury markings caused by predators that …

Ectomycorrhizal Fungi Decompose Soil Organic Matter Using Oxidative Mechanisms Adapted From Saprotrophic Ancestors, Firoz Shah, César Nicolás, Johan Bentzer, Magnus Ellström, Mark Smits, Francois Rineau, Björn Canbäck, Dimitrios Floudas, Robert Carleer, Gerald Lackner, Jana Braesel, Dirk Hoffmeister, Bernard Henrissat, Dag Ahrén, Tomas Johansson, David S. Hibbett, Francis Martin, Per Persson, Anders Tunlid

Biology

Ectomycorrhizal fungi are thought to have a key role in mobilizing organic nitrogen that is trapped in soil organic matter (SOM). However, the extent to which ectomycorrhizal fungi decompose SOM and the mechanism by which they do so remain unclear, considering that they have lost many genes encoding lignocellulose-degrading enzymes that are present in their saprotrophic ancestors. Spectroscopic analyses and transcriptome profiling were used to examine the mechanisms by which five species of ectomycorrhizal fungi, representing at least four origins of symbiosis, decompose SOM extracted from forest soils. In the presence of glucose and when acquiring nitrogen, all species converted …

Human Xq28 Inversion Polymorphism: From Sex Linkage To Genomics - A Genetic Mother Lode, Cait S. Kirby, Natalie Kolber, Asmaa M. Salih Almohaidi, Lou Ann Bierwert, Lori Saunders, Steven Williams, Robert Merritt

Biological Sciences: Faculty Publications

An inversion polymorphism of the filamin and emerin genes at the tip of the long arm of the human X-chromosome serves as the basis of an investigative laboratory in which students learn something new about their own genomes. Long, nearly identical inverted repeats flanking the filamin and emerin genes illustrate how repetitive elements can lead to alterations in genome structure (inversions) through nonallelic homologous recombination. The near identity of the inverted repeats is an example of concerted evolution through gene conversion. While the laboratory in its entirety is designed for college level genetics courses, portions of the laboratory are appropriate …

Beyond The Adaptationist Legacy: Updating Our Teaching To Include A Diversity Of Evolutionary Mechanisms, Rebecca M. Price, Kathryn E. Perez

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

A paradigm shift away from viewing evolution primarily in terms of adaptation - the "adaptationist programme" of Gould and Lewontin - began in evolutionary research more than 35 years ago, but that shift has yet to occur within evolutionary education research or within teaching standards. We review three instruments that can help education researchers and educators undertake this paradigm shift. The instruments assess how biology undergraduates understand three evolutionary processes other than natural selection: genetic drift, dominance relationships among allelic pairs, and evolutionary developmental biology (evo-devo). Testing with these instruments reveals that students often explain a diversity of evolutionary mechanisms …

The Confluence Of Philosophy And Biology: An Excavation Of Philosophical Issues In Molecular And Developmental Biology, Patrick Johnson Mendie, Emmanuel Bassey Eyo (Ph.D)

Journal of Health Ethics

Philosophical evaluations have played an influential role in the growth and development of molecular and developmental biology to ensure that every individual is born healthy, born wanted and has the privilege to fulfil his or her potentials for a life free from disease and disability. This is why it becomes necessary for biologists to carefully understand human genes, evolution, cells and general human anatomy to fulfil this project. During this process, they are faced with challenges where they also lack the foundation on how to solve them. This challenge gave birth to a philosophical excavation of molecular and developmental biology. …

Getting The Hologenome Concept Right: An Eco-Evolutionary Framework For Hosts And Their Microbiomes, K. R. Theis, N. M. Dheilly, J. L. Klassen, R. M. Brucker, J. F. Baines, T. C. G. Bosch, J. F. Cryan, Scott F. Gilbert, C. J. Goodnight, E. A. Lloyd, J. Sapp, P. Vandenkoornhuyse, I. Zilber-Rosenberg, E. Rosenberg, S. R. Bordenstein

Biology Faculty Works

Given the complexity of host-microbiota symbioses, scientists and philosophers are asking questions at new biological levels of hierarchical organization—what is a holobiont and hologenome? When should this vocabulary be applied? Are these concepts a null hypothesis for host-microbe systems or limited to a certain spectrum of symbiotic interactions such as host-microbial coevolution? Critical discourse is necessary in this nascent area, but productive discourse requires that skeptics and proponents use the same lexicon. For instance, critiquing the hologenome concept is not synonymous with critiquing coevolution, and arguing that an entity is not a primary unit of selection dismisses the fact that …

Teaching Evolution: Blog As A Liminal Space, Shylaja Akkaraju, Alexander Wolf

Publications and Research

A threshold concept is a challenging concept that acts as a doorway leading to deeper understanding and a dramatic shift in perception. A learner that is in- volved in grasping a threshold concept is said to be undergoing a threshold expe- rience within a liminal space or learning environment. We used the blog as a lim- inal space for our students to engage with the theory of evolution, which is a threshold concept. In order to teach evolution effectively it is necessary to address both understanding and acceptance of evolutionary theory. To explore the latter in an introductory biology course, …

Home-Field Advantage? Evidence Of Local Adaptation Among Plants, Soil, And Arbuscular Mycorrhizal Fungi Through Meta-Analysis, Megan A. Rúa, Anita Antoninka, Pedro M. Antunes, V. Bala Chaudhary, Catherine Gehring, Louis J. Lamit, Bridget J. Piculell, James D. Bever, Cathy Zabinski, James F. Meadow, Marc J. Lajeunesse, Brook G. Milligan, Justine Karst, Jason D. Hoeksema

Biological Sciences Faculty Publications

Background: Local adaptation, the differential success of genotypes in their native versus foreign environment, arises from various evolutionary processes, but the importance of concurrent abiotic and biotic factors as drivers of local adaptation has only recently been investigated. Local adaptation to biotic interactions may be particularly important for plants, as they associate with microbial symbionts that can significantly affect their fitness and may enable rapid evolution. The arbuscular mycorrhizal (AM) symbiosis is ideal for investigations of local adaptation because it is globally widespread among most plant taxa and can significantly affect plant growth and fitness. Using meta-analysis on 1170 studies …

Friends In Low Places: Responses Of A Benthic Stream Fish To Intra-Guild Alarm Cues, Kelsey Ann Anderson

Graduate Theses/Dissertations

Many aquatic species produce chemical alarm cues that serve as a warning to nearby conspecifics. In mixed-species aggregations, individuals may also benefit by “eavesdropping” on the chemical alarm cues of other species that are in the same prey-guild. Rainbow Darters (Etheostoma caeruleum) are benthic fish that co-occur with native Ozark Minnows (Notropis nubilus), recently-introduced Western Mosquitofish (Gambusia affinis), and native Oklahoma Salamanders (Eurycea tyrnerensis), all of whom are vulnerable to the same predators. We tested the responses of darters to the damage-released alarm cues of conspecifics (positive control), minnows, and mosquitofish; alarm cues from Bumblebee Gobies (Brachygobius doriae) served as …

Tick Genome Assembled: New Opportunities For Research On Tick-Host-Pathogen Interactions, Jose De La Fuente, Robert M. Waterhouse, Daniel E. Sonenshine, R. Michael Roe, Jose M. Ribeiro, David B. Sattelle, Catherine A. Hill

Biological Sciences Faculty Publications

As tick-borne diseases are on the rise, an international effort resulted in the sequence and assembly of the first genome of a tick vector. This result promotes research on comparative, functional and evolutionary genomics and the study of tick-host-pathogen interactions to improve human, animal and ecosystem health on a global scale.

A Novel Method Of Microsatellite Genotyping-By-Sequencing Using Individual Combinatorial Barcoding, Salla Vartia, Jose L. Villanueva-Cañas, John Finarelli, Edward D. Farrell, Patrick C. Collins, Graham M. Hughes, Jeanette E.L. Carlson, David T. Gauthier, Philip Mcginnity, Thomas F. Cross, Richard D. Fitzgerald, Luca Mirimin, Fiona Crispie, Paul D. Cotter, Jens Carlsson

Biological Sciences Faculty Publications

This study examines the potential of next-generation sequencing based 'genotyping-by-sequencing' (GBS) of microsatellite loci for rapid and cost-effective genotyping in large-scale population genetic studies. The recovery of individual genotypes from large sequence pools was achieved by PCR-incorporated combinatorial barcoding using universal primers. Three experimental conditions were employed to explore the possibility of using this approach with existing and novel multiplex marker panels and weighted amplicon mixture. The GBS approach was validated against microsatellite data generated by capillary electrophoresis. GBS allows access to the underlying nucleotide sequences that can reveal homoplasy, even in large datasets and facilitates cross laboratory transfer. GBS …

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 …