Biology Commons^™

The Accelerating Influence Of Humans On Mammalian Macroecological Patterns Over The Late Quaternary, Felisa A. Smith, Rosemary E. Elliott Smith, S. Kathleen Lyons, Jonathan L. Payne, Amelia Villaseñor

School of Biological Sciences: Faculty Publications

The transition of hominins to a largely meat-based diet ~1.8 million years ago led to the exploitation of other mammals for food and resources. As hominins, particularly archaic and modern humans, became increasingly abundant and dispersed across the globe, a temporally and spatially transgressive extinction of large-bodied mammals followed; the degree of selectivity was unprecedented in the Cenozoic fossil record. Today, most remaining large-bodied mammal species are confined to Africa, where they coevolved with hominins. Here, using a comprehensive global dataset of mammal distribution, life history and ecology, we examine the consequences of “body size downgrading” of mammals over the …

H/L Ratio As A Measurement Of Immune Function In Terrapene Ornata Species, Vesa Govori

Honors Program: Senior Projects (Public)

White blood cells are a key part of the immune system, and changes in white cell count can reveal the overall state of health and the immune systems functional ability of a species. White blood such as heterophils and lymphocytes are essential for being able to fight off infections. Analyzing different cell ratios has been commonly done before as a way to observe immune function in bird species as well as other species. Understanding that there are different functions between the different white blood cells provides an extra interesting perspective to what could be happening in the immune system function …

Escaping Death: Naloxone's Chemical Nature And Potential To Combat The Opioid Epidemic, Abigale Miller

Honors Program: Senior Projects (Public)

Naloxone is a life-saving drug with the ability to reverse an opioid overdose. As the opioid epidemic’s death toll rises, we can turn to Naloxone as a tool to combat the crisis. The epidemic, born of corruption, has a wide reach among the people of the United States, with especially firm grasps on middle-aged people, sufferers of chronic pain, white Americans and those living in the eastern portion of the country. Naloxone’s elegant design saves lives by effectively competing for a position on an opioid biding receptor in the brain to almost instantly end an overdose and restore normal breathing. …

Student Perceptions Of Reasons For Lecture And Active Learning, Calan Koch

Honors Program: Senior Projects (Public)

With perceived student resistance to active learning in the classroom, instructors are hesitant to implement such methods into their classroom structure despite how effective they may be. This research seeks to understand student perceptions related to the transition to higher prevalence of active learning techniques. We aimed to find answers to how students perceive the ideal classroom to be structured, what reasons they perceive for lecture and active learning components, and possible explanations to concerns of groupwork during class time. We analyzed 64 interviews with undergraduate biology students at the University of Nebraska- Lincoln, developed coding rubrics from commonly found …

The Nature Of Science As A Foundation For Fostering A Better Understanding Of Evolution, Craig E. Nelson, Lawrence C. Scharmann, Jean Beard, Lawrence I. Flammer

Department of Teaching, Learning, and Teacher Education: Faculty Publications

Misunderstandings of the nature of science (NOS) contribute greatly to resistance to evolutionary theory especially among non-scientific audiences. Here we delineate three extended instructional examples that make extensive use of NOS to establish a foundation upon which to more successfully introduce evolution. Specifically, these instructional examples enable students to consider evolutionary biology using NOS as a lens for interpretation of evolutionary concepts. We have further found, through our respective research efforts and instructional experiences, that a deep understanding of NOS helps students understand and accept the scientific validity of evolution and, conversely, that evolution provides an especially effective context for …

Can Vegfc Form Turing Patterns In The Zebrafish Embyro?, Kenneth Y. Wertheim, Tina Roose

School of Biological Sciences: Faculty Publications

This paper is concerned with a late stage of lymphangiogenesis in the trunk of the zebrafish embryo. At 48 hours pos-fertilisation (HPF), a pool of parachordal lymphangioblasts (PLs) lies in the horizontal myoseptum. Between 48 and 168 HPF, the PLs spread from the horizontal myoseptum to form the throacic duct, dorsal longitudinal lymphatic vessel, and parachordal lymphatic vessel. This paper deals wit hthe potential of vascular endothelial growth factor C (VEGFC) to guide the differentiation of PLs into the mature lymphatic endothelial cells that form the vessels. We built a mathematical model to describe the biochemical interactions between VEGFC, collagen …

Radiomic Feature Stability Across 4d Respiratory Phases And Its Impact On Lung Tumor Prognosis Prediction, Qian Du, Michael Baine, Kyle Bavitz, Josiah Mcallister, Xiaoying Liang, Hongfeng Yu, Jeffrey Ryckman, Lina Yu, Hengle Jiang, Sumin Zhou, Sumin Zhou, Chi Zhang, Dandan Zheng

School of Biological Sciences: Faculty Publications

Radiomic analysis has recently demonstrated versatile uses in improving diagnostic and prognostic prediction accuracy for lung cancer. However, since lung tumors are subject to substantial motion due to respiration, the stability of radiomic features over the respiratory cycle of the patient needs to be investigated to better evaluate the robustness of the interpatient feature variability for clinical applications, and its impact in such applications needs to be assessed. A full panel of 841 radiomic features, including tumor intensity, shape, texture, and wavelet features, were extracted from individual phases of a four-dimensional (4D) computed tomography on 20 early-stage non-small-cell lung cancer …

Ecological Pleiotropy And Indirect Effects Alter The Potential For Evolutionary Rescue, John P. Delong, Jonathan Belmaker

School of Biological Sciences: Faculty Publications

Invading predators can negatively affect naïve prey populations due to a lack of evolved defenses. Many species therefore may be at risk of extinction due to overexploitation by exotic predators. Yet the strong selective effect of predation might drive evolution of imperiled prey toward more resistant forms, potentially allowing the prey to persist. We evaluated the potential for evolutionary rescue in an imperiled prey using Gillespie eco‐evolutionary models (GEMs). We focused on a system parameterized for protists where changes in prey body size may influence intrinsic rate of population growth, space clearance rate (initial slope of the functional response), and …

Influenza H1 Mosaic Hemagglutinin Vaccine Induces Broad Immunity And Protection In Mice, Brigette N. Corder, Brianna L. Bullard, Jennifer L. Debeauchamp, Natalia A. Ilyushina, Richard J. Webby, Eric A. Weaver

School of Biological Sciences: Faculty Publications

Annually, influenza A virus (IAV) infects ~5–10% of adults and 20–30% of children worldwide. The primary resource to protect against infection is by vaccination. However, vaccination only induces strain-specific and transient immunity. Vaccine strategies that induce cross-protective immunity against the broad diversity of IAV are needed. Here we developed and tested a novel mosaic H1 HA immunogen. The mosaic immunogen was optimized in silico to include the most potential B and T cell epitopes (PBTE) across a diverse population of human H1 IAV. Phylogenetic analysis showed that the mosaic HA localizes towards the non-pandemic 2009 strains which encompasses the broadest …

Life Ascending: Mechanism And Process In Physiological Adaptation To High-Altitude Hypoxia, Jay F. Storz, Graham R. Scott

School of Biological Sciences: Faculty Publications

To cope with the reduced availability of O2 at high altitude, air-breathing vertebrates have evolved myriad adjustments in the cardiorespiratory system to match tissue O2 delivery with metabolic O2 demand. We explain how changes at interacting steps of the O2 transport pathway contribute to plastic and evolved changes in whole-animal aerobic performance under hypoxia. In vertebrates native to high altitude, enhancements of aerobic performance under hypoxia are attributable to a combination of environ- mentally induced and evolved changes in multiple steps of the pathway. Additionally, evidence suggests that many high-altitude natives have evolved mechanisms for attenuating maladaptive acclimatization responses to …

Testing The Competition-Colonization Trade-Off And Its Correlations With Functional Trait Variations Among Subtropical Tree Species, Yue Bin, Guojun Lin, Sabrina E. Russo, Zhongliang Huang, Yong Shen, Honglin Cao, Juyu Lian, Wanhui Ye

School of Biological Sciences: Faculty Publications

The competition-colonization trade-off, by which species can partition spatial niches, is a potentially important mechanism allowing the maintenance of species diversity in plant communities. We examined whether there was evidence for this trade-off among tree species in a subtropical forest and how it correlated with eight functional traits. We developed and estimated a metric for colonization ability that incorporates both fecundity and seed dispersal based on seed trap data and the sizes and distributions of adult trees. Competitive ability was estimated as survival probability under high crowding conditions based on neighborhood models. Although we found no significant relationship between colonization …

Gravid Tetragnathid Spiders Show An Increased Functional Response, Mary E. Boswell, John P. Delong

School of Biological Sciences: Faculty Publications

Spiders in the genus Tetragnatha feed on emerging aquatic insects, including mosquitoes and midges, but there is little known about the foraging behavior of these spiders. We hypothesized that female spiders actively developing egg sacs would increase food consumption to provide more energy to produce and provision their eggs. We tested this hypothesis by measuring foraging rates of Tetragnatha spiders kept in jars and provisioned with different levels of midges. We then tested for a difference in the functional response of spiders that did or did not lay egg sacs in their jars. Egg-laying and non-egg-laying spiders showed significantly different …

Modeling Genomes To Phenomes To Populations In A Changing Climate: The Need For Collaborative Networks, Nika Galic, Allyson G. Hindle, John P. Delong, Karen Watanabe, Valery Forbes, C. Loren Buck

School of Biological Sciences: Faculty Publications

Condensed Abstract

Climate is changing globally and its impacts can arise at different levels of biological organization; yet, cross-level consequences of climate change are still poorly understood. Designing effective environmental management and adaptation plans requires implementation of mechanistic models that span the biological hierarchy. Because biological systems are inherently complex and dynamic in nature, dealing with complexities efficiently necessitates simplification of systems or approximation of relevant processes, but there is little consensus on mathematical approaches to scale from genes to populations. Here we present an effort that aims to bring together groups that often do not interact, but that are …

Body Condition Helps To Explain Metabolic Rate Variation In Wolf Spiders, Stella F. Uiterwaal, John P. Delong

School of Biological Sciences: Faculty Publications

1. Metabolism is the fundamental process that powers life. Understanding what drives metabolism is therefore critical to our understanding of the ecology and behavior of organisms in nature.

2. Metabolic rate generally scales with body size according to a power law. However, considerable unexplained variation in metabolic rate remains after accounting for body mass with scaling functions.

3. We measured resting metabolic rates (oxygen consumption) of 227 field-caught wolf spiders. Then, we tested for effects of body mass, species, and body condition on metabolic rate.

4. Metabolic rate scales with body mass to the 0.85 power in these wolf spiders, …

Large Expert-Curated Database For Benchmarking Document Similarity Detection In Biomedical Literature Search, Peter Brown, Relish Consortium, Yaoqi Zhou, Chi Zhang, Tian Gao

School of Biological Sciences: Faculty Publications

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were …

Changes In North American Mammal Niche Preferences From The Late Pleistocene To The Present, Silvia Pineda-Munoz, Anikó Tóth, S. Kathleen Lyons, Yue Wang, Jenny Mcguire

School of Biological Sciences: Presentations

Human population has exponentially grown since the last glaciation, especially across temperate areas with easy access to water sources, excluding mammal species from their former habitats. Thus, we anticipate a change in environmental niche preferences for temperature and precipitation as increased human population forces mammal species into more extreme climates within their environmental tolerances. For our study, we collected species occurrences from 20,000 ybp to the present for 59 North American mammal species. We inferred temperature and precipitation for each location using paleoclimate simulations (CCSM3). Overall, we found that mammals now live in areas that are warmer and dryer on …

Arena Size Modulates Functional Responses Via Behavioral Mechanisms, Stella F. Uiterwaal, Anthony I. Dell, John P. Delong

School of Biological Sciences: Faculty Publications

Laboratory-based functional response experiments, in which foraging rates are measured across a range of resource densities, are central for determining trophic interaction strength. Historically these experiments often are performed in arbitrarily sized arenas, with larger sized organisms generally used in larger arenas. However, arena size influences foraging rates and therefore also estimates of the functional response parameters, particularly space clearance rate (attack rate). We hypothesized that nonrandom movement within arenas by predators and prey may explain this effect. To test this hypothesis, we video-recorded Schizocosa ocreata wolf spiders (predators) and flightless Drosophila melanogaster prey in circular arenas of 3 different …

Ecophysiological Determinants Of Sexual Size Dimorphism: Integrating Growth Trajectories, Environmental Conditions, And Metabolic Rates, Marie-Claire Chelini, John P. Delong, Eileen A. Hebets

Eileen Hebets Publications

Sexual size dimorphism (SSD) often results in dramatic differences in body size between females and males. Despite its ecological importance, little is known about the relationship between developmental, physiological, and energetic mechanisms underlying SSD. We take an integrative approach to understand the relationship between developmental trajectories, metabolism, and environmental conditions resulting in extreme female-biased SSD in the crab spider Mecaphesa celer (Thomisidae). We tested for sexual differences in growth trajectories, as well as in the energetics of growth, hypothesizing that female M. celer have lower metabolic rates than males or higher energy assimilation. We also hypothesized that the environment in …

Physiological And Genomic Evidence That Selection On The Transcription Factor Epas1 Has Altered Cardiovascular Function In Highaltitude Deer Mice, Rena M. Schweizer, Jonathan P. Velotta, Catherine M. Ivy, Matthew R. Jones, Sarah M. Muir, Gideon S. Bradburd, Jay F. Storz, Graham R. Scott, Zachary A. Cheviron

School of Biological Sciences: Faculty Publications

Evolutionary adaptation to extreme environments often requires coordinated changes in multiple intersecting physiological pathways, but how such multi-trait adaptation occurs remains unresolved. Transcription factors, which regulate the expression of many genes and can simultaneously alter multiple phenotypes, may be common targets of selection if the benefits of induced changes outweigh the costs of negative pleiotropic effects. We combined complimentary population genetic analyses and physiological experiments in North American deer mice (Peromyscus maniculatus) to examine links between genetic variation in transcription factors that coordinate physiological responses to hypoxia (hypoxia-inducible factors, HIFs) and multiple physiological traits that potentially contribute to …

Investigating How Faculty Social Networks And Peer Influence Relate To Knowledge And Use Of Evidence-Based Teaching Practices, A. K. Lane, J. Skvoretz, J. P. Ziker, Brian A. Couch, B. Earl, J. E. Lewis, J. D. Mcalpin, L. B. Prevost, S. E. Shadle, Marilyn Stains

School of Biological Sciences: Faculty Publications

Background: Calls for science education reform have been made for decades in the USA. The recent call to produce one million new science, technology, engineering, and math (STEM) graduates over 10 years highlights the need to employ evidence-based instructional practices (EBIPs) in undergraduate STEM classes to create engaging and effective learning environments. EBIPs are teaching strategies that have been empirically demonstrated to positively impact student learning, attitudes, and achievement in STEM disciplines. However, the mechanisms and processes by which faculty learn about and choose to implement EBIPs remain unclear. To explore this problem area, we used social network analysis to …

Tools For Change: Measuring Student Conceptual Understanding Across Undergraduate Biology Programs Using Bio-Maps Assessments, Michelle K. Smith, Sara E. Brownell, Alison J. Crowe, N. G. Holmes, Jennifer K. Knight, Katharine Semsar, Mindi M. Summers, Cole Walsh, Christian D. Wright, Brian A. Couch

School of Biological Sciences: Faculty Publications

Assessing learning across a biology major can help departments monitor achievement of broader program-level goals and identify opportunities for curricular improvement. However, biology departments have lacked suitable tools to measure learning at the program scale. To address this need, we developed four freely available assessments—called Biology-Measuring Achievement and Progression in Science or Bio-MAPS—for general biology, molecular biology, ecology/evolution, and physiology programs. When administered at multiple time points in a curriculum, these instruments can provide departments with information on how student conceptual understanding changes across a major and help guide curricular modifications to enhance learning.

Repeats Of Unusual Size In Plant Mitochondrial Genomes: Identification, Incidence And Evolution, Emily L. Wynn, Alan C. Christensen

School of Biological Sciences: Faculty Publications

Plant mitochondrial genomes have excessive size relative to coding capacity, a low mutation rate in genes and a high rearrangement rate. They also have abundant non-tandem repeats often including pairs of large repeats which cause isomerization of the genome by recombination, and numerous repeats of up to several hundred base pairs that recombine only when the genome is stressed by DNA damaging agents or mutations in DNA repair pathway genes. Early work on mitochondrial genomes led to the suggestion that repeats in the size range from several hundred to a few thousand base pair are underrepresented. The repeats themselves are …

Gene Flow Mediates The Role Of Sex Chromosome Meiotic Drive During Complex Speciation, Colin D. Meiklejohn, Emily L. Landeen, Kathleen E. Gordon, Thomas Rzatkiewicz, Sarah B. Kingan, Anthony J. Geneva, Jeffrey P. Vedanayagam, Christina A. Muirhead, Daniel Garrigan, Daven C. Presgraves, David L. Stern

School of Biological Sciences: Faculty Publications

During speciation, sex chromosomes often accumulate interspecific genetic incompatibilities faster than the rest of the genome. The drive theory posits that sex chromosomes are susceptible to recurrent bouts of meiotic drive and suppression, causing the evolutionary build- up of divergent cryptic sex-linked drive systems and, incidentally, genetic incompatibilities. To assess the role of drive during speciation, we combine high-resolution genetic mapping of X-linked hybrid male sterility with population genomics analyses of divergence and recent gene flow between the fruitfly species, Drosophila mauritiana and D. simulans. Our findings reveal a high density of genetic incompatibilities and a corresponding dearth of gene …

Molecular Machinery Of Auxin Synthesis,Secretion, And Perception In The Unicellular Chlorophyte Alga Chlorella Sorokiniana Utex 1230, Maya Khasin, Rebecca E. Cahoon, Kenneth Nickerson, Wayne R. Riekhof

School of Biological Sciences: Faculty Publications

Indole-3-acetic acid is a ubiquitous small molecule found in all domains of life. It is the predominant and most active auxin in seed plants, where it coordinates a variety of complex growth and development processes. The potential origin of auxin signaling in algae remains a matter of some controversy. In order to clarify the evolutionary context of algal auxin signaling, we undertook a genomic survey to assess whether auxin acts as a signaling molecule in the emerging model chlorophyte Chlorella sorokiniana UTEX 1230. C. sorokiniana produces the auxin indole-3-acetic acid (IAA), which was present in both the cell pellet and …

Modeling Effects Of Ecological Factors On Evolution Of Polygenic Pesticide Resistance, C. V. Haridas, Brigitte Tenhumberg

School of Biological Sciences: Faculty Publications

Widespread use of pesticides has resulted in the evolution of resistance in many insect pests worldwide, limiting their use in pest control. Effective pest and resistance management practices require understanding of the genetics of resistance and the life history of the pest. Most models for pesticide resistance assume that resistance is monogenic, conferred by a single gene. However, resistance could evolve as a polygenic quantitative trait resulting from the action of several genes, especially when pesticide dose is low. Further, fitness of the pest could be density dependent and might depend upon abiotic factors such as temperature. It is not …

Examining Patterns In Nest Predation Using Artificial Nests, Victoria L. Simonsen

School of Natural Resources: Dissertations, Theses, and Student Research

The use of artificial nests to study the predation of avian nests has faced disregard by ecologists due to inconsistencies found between the survival rates of real and artificial nests across studies and reviews. The negative perception of artificial nests providing an inconsistent assessment of survival has thus fostered the perception that artificial nests are a secondary option to be used to overcome logistical hurdles associated with achieving sufficient sample sizes in systems where study species are rare or elusive, or as merely a preliminary method to study predation across gradients. We argue that the greatest mistake ecologists have made …

Nebraska’S Wildlife Club; Nebraska Honors Program Clc Expanded Learning Opportunity Clubs, Alexandrea E. Otto

Honors Program: Expanded Learning Clubs

The goal of the club is to educate and explore with students the wildlife and nature that surrounds them every day. The main focus was to educate students on wildlife native to Nebraska; ranging all the way from West Nebraska to the wildlife found in cities such as Lincoln.

Males And Females Evolve Riskier Traits In Populations With Eavesdropping Parasitoids, Oliver M. Beckers, William E. Wagner

School of Biological Sciences: Faculty Publications

Predation and/or parasitism often limits the evolution of conspicuous male traits and female preferences because conspicuous traits can attract predators or parasites and it is costly for females to associate with males that attract predators or parasites. As a result, males and females in high-risk populations are expected to evolve safer mating behaviors compared to individuals from low-risk populations. We tested this antagonistic selection hypothesis in the field cricket Gryllus lineaticeps. Males produce chirped songs, and both female crickets and the eavesdropping parasitoid fly Ormia ochracea prefer faster chirp rates. The flies attack the field crickets late in the …

Fueling Defense: Effects Of Resources On The Ecology And Evolution Of Tolerance To Parasite Infection, Sarah A. Budischak, Clayton E. Cressler

School of Biological Sciences: Faculty Publications

Resource availability is a key environmental constraint affecting the ecology and evolution of species. Resources have strong effects on disease resistance, but they can also affect the othermain parasite defense strategy, tolerance. A small but growing number of animal studies are beginning to investigate the effects of resources on tolerance phenotypes. Here, we review how resources affect tolerance strategies across animal taxa ranging from fruit flies to frogs to mice. Surprisingly, resources (quality and quantity) can increase or reduce tolerance, dependent upon the particular host-parasite system. To explore this seeming contradiction, we recast predictions of models of sterility tolerance and …

Transcriptomic, Functional, And Network Analyses Reveal Novel Genes Involved In The Interaction Between Caenorhabditis Elegans And Stenotrophomonas Maltophilia, Corin V. White, Michael A. Herman

School of Biological Sciences: Faculty Publications

The bacterivorous nematode Caenorhabditis elegans is an excellent model for the study of innate immune responses to a variety of bacterial pathogens, including the emerging nosocomial bacterial pathogen Stenotrophomonas maltophilia. The study of this interaction has ecological and medical relevance as S. maltophilia is found in association with C. elegans and other nematodes in the wild and is an emerging opportunistic bacterial pathogen. We identified 393 genes that were differentially expressed when exposed to virulent and avirulent strains of S.maltophilia and an avirulent strain of E. coli. We then used a probabilistic functional gene network model (WormNet) to determine …