Biology Commons^™

Epigenetic Response To Challenging Environmental Conditions, Marta Robertson

USF Tampa Graduate Theses and Dissertations

The discovery of epigenetic mechanisms has ignited speculation into their role in ecological and evolutionary processes. In particular, the contribution of epigenetic variation to adaptation or phenotypic plasticity that is distinct from genetic variation would be an important addition to existing evolutionary mechanisms. Although the research of epigenetic mechanisms from an ecological and evolutionary (or eco-evolutionary) perspective has been growing, it is still unclear how epigenetic variation might function in natural populations and settings and to what extent it might serve to mediate population response to changing environmental conditions over time. Over the course of my dissertation, I explored the …

Divergence In Life History Traits Between Two Populations Of A Seed-Dimorphic Halophyte In Response To Soil Salinity, Fan Yang, Jerry M. Baskin, Carol C. Baskin, Xuejun Yang, Dechang Cao, Zhenying Huang

Biology Faculty Publications

Production of heteromorphic seeds is common in halophytes growing in arid environments with strong spatial and temporal heterogeneity. However, evidence for geographic variation (reflecting local adaptation) is almost nonexistent. Our primary aims were to compare the life history traits of two desert populations of this halophytic summer annual Suaeda corniculata subsp. mongolica and to investigate the phenotypic response of its plant and heteromorphic seeds to different levels of salt stress. Dimorphic seeds (F₁) of the halophyte S. corniculata collected from two distant populations (F₀) that differ in soil salinity were grown in a common environment under …

An Efficient Pipeline For Assaying Whole-Genome Plastid Variation For Population Genetics And Phylogeography, Brendan F. Kohrn

Dissertations and Theses

Tracking seed dispersal using traditional, direct measurement approaches is difficult and generally underestimates dispersal distances. Variation in chloroplast haplotypes (cpDNA) offers a way to trace past seed dispersal and to make inferences about factors contributing to present patterns of dispersal. Although cpDNA generally has low levels of intraspecific variation, this can be overcome by assaying the whole chloroplast genome. Whole-genome sequencing is more expensive, but resources can be conserved by pooling samples. Unfortunately, haplotype associations among SNPs are lost in pooled samples and treating SNP frequencies as independent estimates of variation provides biased estimates of genetic distance. I have developed …

The Population Genetics Of Morro Bay Eelgrass (Zostera Marina), Julia Gardner Harencar

Master's Theses

Seagrass populations are in decline worldwide. Zostera marina (eelgrass), one of California’s native seagrasses, is no exception to this trend. In the last 8 years, Morro Bay, California has lost 95% of its eelgrass. Eelgrass is an ecosystem engineer, providing important ecosystem services such as sediment stabilization, nutrient cycling, and nursery habitats for fish. The failure of recent restoration efforts necessitates a better understanding of the causes of eelgrass decline in this estuary. Previous research on eelgrass in California has demonstrated a link between population genetic diversity and eelgrass bed health, ecosystem functioning, and resilience to disturbance and extreme climatic …

The Weevil Next Door: Exploring The Impact Of Associational Effects On C. Pitcheri To Better Biological Control Practices, Tina Czaplinska

Lawrence University Honors Projects

Lake Michigan dwelling dune thistle, Circium pitcheri, is a federally threatened plant, whose reproduction is affected by a non-native weevil, Larinus planus. Originally introduced as a biological control agent to combat the spread of Canada thistle, Circium arvense, this weevil is instead using C. pitcheri as a host for its larvae. Associational susceptibility is an important factor to consider in hopes of preventing the damage to this endangered plant. The goal of this study was to observe L. planus behavior to determine why there is a correlation between increased density of beach grass and high levels of C. …

Let The Seeds Fall Where They May: Investigating The Effect Of Landscape Features On Fine-Scale Seed Dispersal, Monica R. Grasty

Dissertations and Theses

Seed dispersal is a crucial ecological and evolutionary process that allows plants to colonize sites and expand their ranges, while also reducing inbreeding depression and facilitating the spread of adaptive genetic variation. However, our fundamental understanding of seed dispersal is limited due to the difficulty of directly observing dispersal events. In recent years, genetic marker methods have furthered our understanding of colonization and range expansion due to seed dispersal. Most investigations focus on regional scales of dispersal, due to low levels of variation in the chloroplast genome (cpDNA), which can serve as an indirect measure of seed dispersal. Here, I …

Differentiating The Neches River Rose Mallow (Hibiscus Dasycalyx) From Its Congeners By Means Of Phylogenetics And Population Genetics, Julia Norrell

Biology Theses

This study used molecular phylogenetic methods to attempt to resolve the taxonomic status of the federally threatened East Texas-endemic wildflower, the Neches River Rose Mallow (Hibiscus dasycalyx). Hibiscus dasycalyx co-occurs with two other closely related congeners that are currently not of conservation concern: the halberdleaf rose mallow (H. laevis); and the crimson-eyed rose mallow (H. moscheutos). This study assessed the phylogeny of these three Hibiscus species, and attempted to determine if there is possible hybridization occurring between them. To this end, Restriction Site Associated DNA Sequencing (RAD-Seq), a Next Generation Sequencing method, was used …

Transciptome Analysis Illuminates The Nature Of The Intracellular Interaction In A Vertebrate-Algal Symbiosis, John A. Burns, Huanjia Zhang, Elizabeth M. Hill, Eunsoo Kim, Ryan R. Kerney

Biology Faculty Publications

During embryonic development, cells of the green alga Oophila amblystomatis enter cells of the salamander Ambystoma maculatum forming an endosymbiosis. Here, using de novo dual-RNA seq, we compared the host salamander cells that harbored intracellular algae to those without algae and the algae inside the animal cells to those in the egg capsule. This two-by-two-way analysis revealed that intracellular algae exhibit hallmarks of cellular stress and undergo a striking metabolic shift from oxidative metabolism to fermentation. Culturing experiments with the alga showed that host glutamine may be utilized by the algal endosymbiont as a primary nitrogen source. Transcriptional changes in …

Determination Of Seed Viability Of Eight Wild Saudi Arabian Species By Germination And X-Ray Tests, Turki A. Al-Turki, Carol C. Baskin

Biology Faculty Publications

Our purpose was to evaluate the usefulness of the germination vs. the X-ray test in determining the initial viability of seeds of eight wild species (Salvia spinosa, Salvia aegyptiaca, Ochradenus baccatus, Ochradenus arabicus, Suaeda aegyptiaca, Suaeda vermiculata, Prosopisfarcta and Panicumturgidum) from Saudi Arabia. Several days were required to determine viability of all eight species via germination tests, while immediate results on filled/viable seeds were obtained with the X-ray test. Seeds of all the species, except Sa.aegyptiaca, showed high viability in both the germination (98–70% at 25/15 °C, 93–66% at 35/25 °C) …

Vegetative Rapid Assessment And Habitat Quality Analysis Of Steidtmann Woods, Sarah Mae Bail

Honors Projects

Due to invasive species and the assumption of an unhealthy ecosystem, Steidtmann Woods is an underutilized piece of land owned by Bowling Green State University. However, the property had never been analyzed. The proposed hypothesis was that Steidtmann was indeed in destress and its ecosystem could benefit from intervention—removal of invasive species and supplementation of natives. Through a rapid vegetative analysis, data was collected in several regions of the woods to identify what navies and non-natives were present as well as to identify their proportions. With that data, the species evenness, richness, and diversity was calculated; first, with raw field …

Range-Wide Prevalence And Impacts Of Pseudocercosporella Inconspicua On Lilium Grayi And An Assessment Of L. Superbum And L. Michauxii As Reservoirs, Cindy L. Barrett

Electronic Theses and Dissertations

Lilium grayi (Gray’s Lily), a southern Appalachian endemic species, is threatened by a Lilium-specific fungal pathogen, Pseudocercosporella inconspicua. The disease is characterized by tan lesions that can cause early senescence, while also lowering seed production and viability. This project tested for P. inconspicua conidia and accessed health at nine locations. The disease was present and ubiquitous across the range of L. grayi. Through identification of P. inconspicua conidia in the field, L. superbum (Turk’s Cap Lily) was identified as an additional host, while L. michauxii (Michaux’s Lily) was disease-free. However, infection was inducible in both species. With …

Variation In Density Dependent Seedling Survival Across Forests Of Different Successional Age And Hunting Protection Status, Nohemi Huanca-Nunez

School of Biological Sciences: Dissertations, Theses, and Student Research

Over 50% of the original extent of tropical forests has been cleared. Restoration of secondary forests is important for maintaining the ecosystem services that mature tropical forests provide. Density dependence (DD) is thought to be a major mechanism for shaping forest community structure and may cause reduced spatial aggregation among individuals of the same species, allowing for maintenance of diversity. While much research has focused on DD in mature tropical forests, few studies have examined how DD may influence community structure in secondary forests, many of which are also exposed to hunting. There are several important agents of negative and …

Factors Influencing Induction Of Desiccation Tolerance In Bryophytes: Redefining Fundamental Aspects Of The Organism’S Relationship With The Environment In Xeric Habitats, Joshua Lee Greenwood

UNLV Theses, Dissertations, Professional Papers, and Capstones

If one wishes to understand the ecological role, range, habitat preferences, selective pressures, reproduction, response to climate change, and the potential for survival under climactic change, range expansion and range contraction for species and populations of bryophytes, an understanding of their survival of the desiccated state, is essential. In order to further our understanding of desiccation tolerance in mosses, three projects were undertaken. The first of these investigated the nature of desiccation tolerance in mosses, specifically if desiccation tolerance can be induced; thereby providing a desiccation tolerant phenotype in a moss species generally considered desiccation sensitive (Physcomitrella patens, the model …

Dark-Adapted Fluorescence And Stomatal Conductance After Dcmu (3-(3,4-Dichlorophenyl)-1, 1-Dimethylurea)) Exposure On Malva Parviflora Plants, Piueti Maka, Mia Bryant, Isabelle Sarwono

Featured Research

The purpose of this experiment was to determine the disturbance effect of indirect exposure to DCMU (3-[3,4-dichlorophenyl]-1,1-dimethylurea), a popular herbicide, on dark adapted fluorescence and stomatal conductance in Malva parviflora plants. We utilized a test site exposed to sunlight and free from other external interference. Two main apparatuses were used to collect data; stomatal conductance was measured by a leaf porometer, and dark-adapted fluorescence (Fv/Fm) was measured using a Pulse Modulated Fluorometer. Our data yielded significant comparison results for dark-adapted fluorescence (P0.05). Additionally, observations six days after disturbance showed a drastic presence of hollyhock rust (Puccinia malvacearum) and …

Photoprotection Adaptiveness In Native (Lupinus 
Succulentus) And Invasive (Malva Parviflora) Heliotropic Plants, Joseph Davidson, Cameron Juarez, Collin Scott

Featured Research

Addressed here is the question of whether invasive heliotropic plants can adapt better than native heliotropic plants, to conditions in which their solar tracking capabilities are hindered. In order to test this, a heliotropic species native to Southern California (Lupinus succulentus) was compared to a weedy heliotropic species invasive to Southern California (Malva parviflora). We hypothesized that the photoprotection mechanisms of M. parviflora would adapt better to being restrained as it is an invasive species and it was more abundant in the area. Values of Fv’/Fm’ and qN were measured in order to compare the efficacy …

Reflectance, Transmittance, And Absorbance Values In Salvia Apiana
 Result In Better Performance Than Salvia Mellifera In Drought- Like Conditions, Haley Bekins, Caroline Boone, Kristen Hardin

Featured Research

Salvia apiana, due to the physically lighter color and thickness of the leaves, will have higher reflectance values, lower transmittance values, and lower absorbance values than Salvia mellifera. These measurements exemplify characteristics of a better adapted species for droughts, and then the absorption values can be used to calculate more information on the species like ERT. We measured transmittance and reflectance of six leaves from randomly selected plants of both species through the use of an integrating sphere. After obtaining the R and T value of each plant, we calculated the leaf absorbance,α. This was done by using the …

A Comparative Study Of Adults Vs. Resprouts’ Stomatal Conductance And Xylem Water Potential In Malosma Laurina, Lauren Dam, Brinna Lee, Sarah Dahlberg, Stephen Davis

Featured Research

The purpose of this study is to compare the stomatal conductance and xylem water potential between adults and resprouts of Malosma laurina growing at the Drescher Campus at Pepperdine University. Our data suggest that stomatal conductance and xylem water potential of adult and resprout M. laurina are not significantly different (p = 0.09312, p = 0.7064 respectively), implying that M. laurina at that study site has had sufficient time to recover from the drought due to the increased levels of rainfall.

A Comparison Of Photoprotection In C3 Plants Between A Native And An Invasive Species, T. Cao, M. Field, K. Godon

Featured Research

Now more so than ever with the increasing demands placed upon plant species as a direct result of climate change, competition between native and invasive species determines which species are able to survive and reproduce. Biologically the two species, native and invasive, carry out the same functions yet it is in how they carry out said functions that they differ. Prior to the commencement of the study the belief was held that the invasive species (here Avena) would contain increased photoprotection than the native species (here Elymus) for it to possess a competitive advantage. Testing of the stated hypothesis including …

Comparative Fitness Of Transplanted Nassella Pulchra: A Study Of Native And Invasive Grasses, Grace Palmer, Yash Pandey, Isabelle Panos

Featured Research

Previous study of the fitness of California, perennial N. pulchra was conducted at the transplant garden on the Drescher campus of Pepperdine University in the spring of 2016. A follow up study was conducted to understand how the recent increase in rainfall has affected the comparative health of N. pulchra in the transplant garden and in the wild, as well as the health of the invasive, annual grass A. fatua. The height, water potential, photoprotection, and stomatal conductance were measured in transplant N. pulchra, wild N. pulchra, and the competing A. fatua. It was hypothesized that A. fatua …

Solar Tracking Fitness In Native Lupulinus Succulentus Vs. Non-Native Malva Sylvestris, Kathryn Maidlow, Logan Scott

Featured Research

For this experiment, we hypothesized, that while both native and non-native species use solar tracking, the native species Lupulinus succulentus (bluebonnet) will solar track to increase light levels with low leaf temperatures; however, the non-native species Malva sylvestris (cheeseweed) will solar track to increase light levels with an elevated leaf temperature over the native species. Solar tracking was also hypothesized as a significant benefit to each plant species, thus we assumed that if a leaf was prevented from solar tracking that we would see a difference between the solar trackers and non-solar trackers of each species. We decided to use …

Comparison Of Physiological Measurements And Water Potential Of Malosma Laurina During And After The Drought In Southern California, Nicolette Jessen, Kirstin Van Fleet, Rachel White

Featured Research

After 5 years of drought, southern California has recently experienced increases in precipitation. Malosma laurina is a chaparral shrub that displays vulnerability to fungal infection during severe drought conditions, particularly in its adult branches, resulting in severe dieback throughout the Santa Monica Mountains. M. laurina is known to produce resprout leaves during times of environmental stress that are less affected by the fungus based on its ability to maintain water status and thus are more capable of displaying resilience in more favorable environmental conditions. We hypothesize that the increase in rain will not be enough to alter the vitality of …

Dna Barcoding Reveals A New Morphotype Of The Sugar Kelp, Saccharina Latissima, Dallin Brimley, Zakery Ford, Travis Gould, Brandon Guerra, Emily Haggett, Ian Jones, Elyse Johnson, Ken Peterson, Matthew Prout

Thinking Matters Symposium Archive

Phytoplankton blooms follow predictable annual cycles in the Gulf of Maine, characterized by a large spring bloom and a smaller bloom in the fall. Marine phytoplankton form the foundation of primary production in Gulf of Maine waters, and thus community changes in composition, and abundance could have cascading effects on our coastal ecosystems.

We set out to monitor the community composition, diversity, and abundance of the spring micro-phytoplankton bloom, at a Friends of Casco Bay water quality monitoring site, in South Portland, Maine. The Gulf of Maine is experiencing accelerated warming rates, and this type of monitoring can aid in …

Black Bugbane & The Blues: Interactions Between Our Wildflower Of The Year And The Insect World, W. John Hayden

Biology Faculty Publications

No, this article has nothing to do with American Roots music. Black Bugbane is one of several common names for the 2017 VNPS Wildflower of the Year, Actaea racemosa. And Blues refers to a subfamily of lycaenid butterflies, commonly referred to as Blues or Azures. The interactions between Black Bugbane, a.k.a., Black Cohosh, Appalachian Azure butterflies (Celastrina neglectamajor), and ants was recently summarized by VNPS charter member and past president Nicky Staunton (2015). In brief, Black Bugbane is the sole food source for caterpillars of Appalachian Azure butterflies, a situation that, superficially, might seem like any other caterpillar and host …

Abiotic Conditions Of Rare Pitcher's Thistle Attract Selection By An Invasive Weevil, Monica Paniagua Montoya

Lawrence University Honors Projects

Plant associations occur when host selection of a focal plant is reduced or increased by the presence of another plant species. Larinus planus is an invasive weevil whose larvae feed in the flower heads of native and federally threatened Pitcher’s thistle (Cirsium pitcheri). Studies have linked the presence of neighboring plants to increased host selection of Pitcher’s thistle by the weevil, but the factors contributing to host selection remain unknown. In our study, we determined if there were differences among abiotic factors, host selection and weevil behavior at Pitcher’s thistles surrounded by beach grass, sand and at high …

Does Riparian Forest Invasion By The Exotic Shrub Amur Honeysuckle Influence Nutrient Dynamics In Headwater Streams?, Charlotte Anne Shade

Honors Theses

Lonicera maackii (Amur honeysuckle) invasion is extensive in forests across much of Ohio and the Midwest. Amur honeysuckle has been shown to influence headwater streams and its organisms, which depend on a certain water chemistry to survive. Little has been done to understand how honeysuckle affects water chemistry and nutrient cycling. As honeysuckle canopies prevent native organic matter from entering the streams below, while also adding its own organic matter that is high in nitrogen and phosphorus, and low in lignin, the amount and types of nutrients present in both forests and streams may be significantly altered. Over a one-year …

The Arabidopsis Kinesin-4, Fra1, Requires A High Level Of Processive Motility To Function Correctly, Anindya Ganguly, Logan Demott, Ram Dixit

Biology Faculty Research

Processivity is important for kinesins that mediate intracellular transport. Structure–function analyses of N-terminal kinesins (i.e. kinesins comprising their motor domains at the N-terminus) have identified several non-motor regions that affect processivity in vitro. However, whether these structural elements affect kinesin processivity and function in vivo is not known. Here, we used an Arabidopsis thaliana kinesin-4, called Fragile Fiber 1 (FRA1, also known as KIN4A), which is thought to mediate vesicle transport, to test whether mutations that alter processivity in vitro lead to similar changes in behavior in vivo and whether processivity is important for the function of FRA1. We …

Hydraulic Mechanisms Of Fungal-Induced Dieback In A Keystone Chaparral Species During Unprecedented Drought In California, Natalie M. Aguirre, Marissa E. Ochoa, Helen I. Holmlund, Frank E. Ewers, Stephen D. Davis

Seaver College Research And Scholarly Achievement Symposium

Between 2012-2016, southern California experienced unprecedented drought that caused dieback in Malosma laurina, a keystone species of chaparral shrub communities. Dieback was especially severe in coastal exposures of the Santa Monica Mountains, leading to whole plant mortality exceeding 50% at some sites. We hypothesized that the endophytic fungus causing the dieback, Botryosphaeria dothidea, was successful in invading the xylem tissue of M. laurina because of protracted water stress, carbon starvation, or a combination of the two. We tested these possibilities in a controlled pot experiment by comparing three treatments, each inoculated with the fungus: (1) irrigated controls (2) …

Small Scale Heterogeneity In Vegetation Structure In A Patch-Burn-Grazing Landscape, Eric G. Behrens

UNO Student Research and Creative Activity Fair

Disturbances are drivers of spatial change in the plant communities of the tallgrass prairie ecosystem. Fire and large herbivore grazing are prevalent disturbances that maintain the vegetation structure and create spatial heterogeneity in vegetation at various scales. The fire-grazing disturbance interaction occurs when areas that have been recently burned are followed by intense grazing due to the high quality of forage regrowth. This interaction has been managed in tallgrass prairies in a homogenous method using uniform burning and grazing and a heterogeneous method using patch-burn-grazing (PBG). Vegetation heterogeneity at a large scale has been studied in PBG and uniformly managed …

Competition From Bromus Tectorum Removes Differences Between Perennial Grasses In N Capture And Conservation Strategies, Rebecca E. Drenovsky, Jeffrey T. Walker, J. J. James

Biology

Background and aims

Competition from the annual grass Bromus tectorum threatens aridland perennial bunchgrass communities. Unlike annuals, perennials must allocate part of their first year nitrogen (N) budget to storage rather than growth, potentially placing them at a competitive disadvantage.

Methods

We evaluated N acquisition and conservation for two perennial bunchgrasses, Agropyron desertorum and Pseudoroegneria spicata, at the seedling stage to investigate potential trade-offs between storage and growth when grown with and without B. tectorum under two levels of soil N.

Results

Agropyron desertorum had higher growth rates, N uptake, and N productivity than P. spicata when grown without …

Invasive Species Control And Perennial Plant Establishment In Antelope Pasture, Pocatello, Blm, Kari E. Veblen

Funded Research Records

No abstract provided.