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Articles 5671 - 5700 of 19755

Full-Text Articles in Ecology and Evolutionary Biology

Ecological Controls On The Campanian Distribution Of Hesperornis (Aves: Hesperornithiformes) In The Western Interior Seaway, Blake Chapman Jan 2021

Ecological Controls On The Campanian Distribution Of Hesperornis (Aves: Hesperornithiformes) In The Western Interior Seaway, Blake Chapman

Master's Theses or Doctor of Nursing Practice

The epicontinental Western Interior Seaway (WIS) of Late Cretaceous North America provided a unique marine habitat for cephalopods, fish, marine reptiles, and the foot-propelled diving seabird Hesperornis. While several predator-prey relationships among Hesperornis or other hesperornithiforms and other WIS animals have been hypothesized based on gut contents, bite marks, and coprolites/colonites, ecological relationships have not been quantitatively tested. Paleontological species distribution modeling (SDM) studies have focused on extinct non-marine taxa and marine invertebrates, with only two marine vertebrate studies of extant taxa. Here, two SDM methods were used to test the influence of vertebrate faunas, sedimentary rock type, paleogeography, …


Patterns Of Dispersion, Movement And Feeding Of The Sea Urchin Lytechinus Variegatus, And The Potential Implications For Grazing Impact On Live Seagrass, Adrianna Parson, Joseph M. Dirnberger, Troy Mutchler Jan 2021

Patterns Of Dispersion, Movement And Feeding Of The Sea Urchin Lytechinus Variegatus, And The Potential Implications For Grazing Impact On Live Seagrass, Adrianna Parson, Joseph M. Dirnberger, Troy Mutchler

Gulf and Caribbean Research

The sea urchin Lytechinus variegatus is a known grazer of both living and dead tissue of turtlegrass, Thalassia testudinum, occasionally denuding large areas of seagrass. Field studies have attempted to assess effects of herbivory on seagrass by enclosing urchins at various densities. However, it is unclear how unrestricted urchins affect seagrass at lower densities more typically observed in the field. This study describes movement, feeding, and distribution of L. variegatus within beds of T. testudinum in St. Joseph Bay, Florida (USA) to quantify this urchin’s impact as a seagrass grazer. Urchins were absent from portions of seagrass beds closest to …


How A Simple Question About Freshwater Inflow To Estuaries Shaped A Career, Paul A. Montagna Jan 2021

How A Simple Question About Freshwater Inflow To Estuaries Shaped A Career, Paul A. Montagna

Gulf and Caribbean Research

Chance and good luck led to a career studying how freshwater inflow drives estuary processes. In 1986, someone asked me: How much fresh water has to flow to a bay for it to be healthy? The question shaped my career. There is probably no better place on Earth to compare effects caused by inflow differences than the Texas coast, because the major estuarine systems lie in a climatic gradient where runoff decreases 56—fold from the Louisiana border in the northeast to the Mexico border in the southwest. This estuary—comparison experiment was used to study inflow effects. The science evolved from …


Elevating Dissolved Oxygen—Reflections On Developing And Using Long-Term Data, Nancy N. Rabalais Jan 2021

Elevating Dissolved Oxygen—Reflections On Developing And Using Long-Term Data, Nancy N. Rabalais

Gulf and Caribbean Research

This prospectus took me about as long to generate as my 36—year record of working on the issue of northern Gulf of Mexico (nGOM) oxygen deficiency, or so I felt. There was so much to cover, but I focused on the issue of hypoxia on the Louisiana continental shelf from the early 1980s to present and my participation in the research and outreach. Not that I was ignoring other aspects of my academic research career (e.g., stone crab populations and their differences in physiology and larval development along the nGOM coast; settlement of crab megalopae, especially blue crabs, on artificial …


Scaling The Effects Of Ocean Acidification On Coral Growth And Coral-Coral Competition On Coral Community Recovery, Nicolas R. Evensen, Yves-Marie Bozec, Peter J. Edmunds, Peter J. Mumby Jan 2021

Scaling The Effects Of Ocean Acidification On Coral Growth And Coral-Coral Competition On Coral Community Recovery, Nicolas R. Evensen, Yves-Marie Bozec, Peter J. Edmunds, Peter J. Mumby

Biological Sciences Faculty Publications

Ocean acidification (OA) is negatively affecting calcification in a wide variety of marine organisms. These effects are acute for many tropical scleractinian corals under short-term experimental conditions, but it is unclear how these effects interact with ecological processes, such as competition for space, to impact coral communities over multiple years. This study sought to test the use of individual-based models (IBMs) as a tool to scale up the effects of OA recorded in short-term studies to community-scale impacts, combining data from field surveys and mesocosm experiments to parameterize an IBM of coral community recovery on the fore reef of Moorea, …


Biolability Of Fresh And Photodegraded Pyrogenic Dissolved Organic Matter From Laboratory-Prepared Chars, K. W. Bostick, A. R. Zimmerman, A. I. Goranov, S. Mitra, P. G. Hatcher, A. S. Wozniak Jan 2021

Biolability Of Fresh And Photodegraded Pyrogenic Dissolved Organic Matter From Laboratory-Prepared Chars, K. W. Bostick, A. R. Zimmerman, A. I. Goranov, S. Mitra, P. G. Hatcher, A. S. Wozniak

Chemistry & Biochemistry Faculty Publications

Pyrogenic dissolved organic matter (pyDOM) is known to be an important biogeochemical constituent of aquatic ecosystems and the carbon cycle. While recent studies have examined how pyDOM production, composition, and photolability varies with parent pyrogenic solid material type, we lack an understanding of potential microbial mineralization and transformation of pyDOM in the biogeosphere. Thus, leachates of oak, charred at 400 °C and 650 °C, as well as their photodegraded counterparts were incubated with a soil‐extracted microbial consortium over 96 days. During the incubation, significantly more carbon was biomineralized from the lower versus higher temperature char leachate (45% vs. 37% lost, …


African Environmental Ethics: Keys To Sustainable Development Through Agroecological Villages, Charles Verharen, Flordeliz Bugarin, John Tharakan, Enrico Wensing, Bekele Gutema, Joseph Fortunak, George Middendorf Jan 2021

African Environmental Ethics: Keys To Sustainable Development Through Agroecological Villages, Charles Verharen, Flordeliz Bugarin, John Tharakan, Enrico Wensing, Bekele Gutema, Joseph Fortunak, George Middendorf

Center for Global Health Publications

This essay proposes African-based ethical solutions to profound human problems and a working African model to address those problems. The model promotes sustainability through advanced agroecological and information communication technologies. The essay's first section reviews the ethical ground of that model in the work of the Senegalese scholar, Cheikh Anta Diop. The essay's second section examines an applied African model for translating African ethical speculation into practice. Deeply immersed in European and African ethics, Godfrey Nzamujo developed the Songhaï Centers to solve the problem of rural poverty in seventeen African countries. Harnessing advanced technologies within a holistic agroecological ecosystem, Nzamujo's …


Lepidopteran Granivory Reduces Seed Counts In A Rare Species Of Riparian Scour Prairies, Cheyenne Moore, Angela J. Mcdonnell, Scott Schuette, Christopher T. Martine Jan 2021

Lepidopteran Granivory Reduces Seed Counts In A Rare Species Of Riparian Scour Prairies, Cheyenne Moore, Angela J. Mcdonnell, Scott Schuette, Christopher T. Martine

Faculty Journal Articles

In Pennsylvania Baptisia australis var. australis is found along only four waterways: the Allegheny River, Youghiogheny River, Clarion River, and Red Bank Creek. Because of its limited distribution and small number of extant populations, the species is considered state-threatened in Pennsylvania. In addition, the riparian prairie habitat that Pennsylvania Baptisia australis var. australis is restricted to is also in decline and considered vulnerable. Because of these conservation concerns, insights into the natural history of the taxon in the state is valuable and will inform conservation efforts. Field surveys and fruit collections along the Allegheny River and herbarium collections were used …


Scoping Review Of Distribution Models For Selected Amblyomma Ticks And Rickettsial Group Pathogens, Catherine A. Lippi, Holly D. Gaff, Alexis L. White, Sadie J. Ryan Jan 2021

Scoping Review Of Distribution Models For Selected Amblyomma Ticks And Rickettsial Group Pathogens, Catherine A. Lippi, Holly D. Gaff, Alexis L. White, Sadie J. Ryan

Biological Sciences Faculty Publications

The rising prevalence of tick-borne diseases in humans in recent decades has called attention to the need for more information on geographic risk for public health planning. Species distribution models (SDMs) are an increasingly utilized method of constructing potential geographic ranges. There are many knowledge gaps in our understanding of risk of exposure to tick-borne pathogens, particularly for those in the rickettsial group. Here, we conducted a systematic scoping review of the SDM literature for rickettsial pathogens and tick vectors in the genus Amblyomma. Of the 174 reviewed articles, only 24 studies used SDMs to estimate the potential extent …


Spatiotemporal Interactions Between Deer And Cattle, Sydney Brewer Jan 2021

Spatiotemporal Interactions Between Deer And Cattle, Sydney Brewer

Honors Program: Senior Projects (Public)

Mule deer, white-tailed deer, and cattle are sympatric on the landscape throughout many portions of Nebraska and encounter each other in time and space. By considering variation in daily activity patterns and non-random patterns in the timing of passage through specific locations, we can better understand whether animals may be avoiding each other temporally when sharing space. I investigated temporal activity patterns and avoidance/attraction ratios to investigate if deer altered their activity patterns in the presence of cattle and if they exhibited avoidance at a study site near McCook, Nebraska, USA. We collected data from 19 game cameras that were …


Southeast Michigan Wastewater Treatment Plants As Potential Sources Of Microplastic Pollution In The Rouge River And Huron River, Jennifer Troost Jan 2021

Southeast Michigan Wastewater Treatment Plants As Potential Sources Of Microplastic Pollution In The Rouge River And Huron River, Jennifer Troost

Master's Theses and Doctoral Dissertations

Plastic pollution is a global issue affecting the health and stability of freshwater and marine environments. Microplastics can be introduced into waterways from a variety of sources, such as agricultural runoff, anthropogenic litter, and wastewater treatment plants (WWTPs). To determine whether WWTPs are a source of microplastics to the Lower Rouge and Huron Rivers, we measured microplastic load upstream and downstream of two Southeast Michigan wastewater treatment plants: the Ann Arbor Wastewater Treatment Plant and Ypsilanti Community Utilities Authority (YCUA). Results from this study indicated that YCUA, which discharges into a small stream with limited watershed inputs, is a significant …


Defining Plant Ecological Specialists And Generalists: Building A Framework For Identification And Classification, Alex N. Kirsch Jan 2021

Defining Plant Ecological Specialists And Generalists: Building A Framework For Identification And Classification, Alex N. Kirsch

All Graduate Theses, Dissertations, and Other Capstone Projects

This thesis is submitted in two chapters. The first chapter contains background research, literature review, relevant information, and justification for the primary study. The second chapter is written as a standalone paper for submission to Ecology and Evolution, that can be read and interpreted independently of the first chapter. Specialization is a widespread but highly ambiguous and context dependent ecological concept. Here, we construct a framework to assess specialization using an objective, metric-based approach, utilizing study system Quercus. To create Metric-Based Specialization rankings, metrics related to specialization were gathered for 141 Quercus species (Number of distinct inhabited ecoregions, extent of …


Vole Population Dynamics In Cover Crops Transitioning To Soybeans With Integrated Pest Management By Habitat Modification, Jena L. Nierman Jan 2021

Vole Population Dynamics In Cover Crops Transitioning To Soybeans With Integrated Pest Management By Habitat Modification, Jena L. Nierman

Theses and Dissertations--Forestry and Natural Resources

The use of cover crops has been a wildly used method in rotational row crop production. Cover crops have minimized soil runoff and aided in maintaining nutrients in agricultural fields. Increased use of cover crops has seen a corresponding increase in the amount of damage done to soybeans by voles. Currently, there are no mitigation methods that successfully decrease vole populations in agricultural fields. The use of habitat manipulation as an integrated pest management solution has not been studied as a practical solution for vole population management. During 2019 and 2020, I tested the impacts of various cover crop termination …


Invasive Bullfrogs Maintain High Levels Of Immune Gene Diversity Despite Elevated Bd Infection Relative To Native Populations, Jacob Lafond Jan 2021

Invasive Bullfrogs Maintain High Levels Of Immune Gene Diversity Despite Elevated Bd Infection Relative To Native Populations, Jacob Lafond

Electronic Theses and Dissertations, 2020-2023

Maintenance of genetic diversity at ecologically-relevant loci may be important for allowing invasive populations to become established despite decreases in genomic diversity due to founder effects. To evaluate this prediction, we compared genetic diversity at an expressed MHC class IIß gene fragment to a 909 bp region of the neutral cytochrome b (cytb) locus from 20 populations of the American bullfrog (Rana catesbeiana) across its North American invasive and native ranges and quantified the presence of Batrachochytrium dendrobatidis (Bd), a pathogen, for which R. catesbeiana is a vector species. We recovered 28 unique MHC alleles and found that invasive populations …


Aquatic Macrophyte Communities In Five Sibley County (Minnesota) Lakes And The Factors That Affect Their Distribution, Samuel A. Schmid Jan 2021

Aquatic Macrophyte Communities In Five Sibley County (Minnesota) Lakes And The Factors That Affect Their Distribution, Samuel A. Schmid

All Graduate Theses, Dissertations, and Other Capstone Projects

The purposes of this study are to 1) quantify the shifts in the macrophyte community structure of five lakes in Sibley County, and 2) to assess the relationships between the macrophyte communities and abiotic factors in these five lakes. In both the early and late growing season of 2019, point-intercept surveys were conducted on High Island Lake, Titlow Lake, Schilling Lake, Silver Lake, and Clear Lake. At each point, water depth was recorded, and all macrophytes sampled were identified and recorded as “present.” There was not a late season survey conducted for High Island Lake in 2019 due to a …


How Bavinck Responds To The Challenges Of The Theory Of Evolution: The Primacy Of Biblical Revelation, Isaias D'Oleo Ochoa Jan 2021

How Bavinck Responds To The Challenges Of The Theory Of Evolution: The Primacy Of Biblical Revelation, Isaias D'Oleo Ochoa

CTS Student Publications and Creative Works

In his discussion of evolution, Bavinck offers a modified theory of development, rooted not under a mechanistic and naturalistic worldview, as Darwin does, but under a “theistic-friendly” framework. This article argues that Bavinck’s discussion of evolution as a whole endorses a modified Aristotelian/ Thomistic framework in order to understand the theory of development, and thus overcomes the challenges raised by Darwin’s naturalistic worldview to biblical revelation.


Evaluation Of Methods For The Restoration Of Native Grasslands On Abandoned Center Pivots In The Sandsage Prairies Of Southwestern Kansas, Alonso Barragan-Martinez Jan 2021

Evaluation Of Methods For The Restoration Of Native Grasslands On Abandoned Center Pivots In The Sandsage Prairies Of Southwestern Kansas, Alonso Barragan-Martinez

Master's Theses or Doctor of Nursing Practice

Throughout southwestern Kansas thousands of acres of native grassland have been converted to cropland for agricultural use, reducing native prairie by over 60% in the sandsage prairie. Due to low precipitation and arid conditions, much of these croplands are irrigated by center pivot irrigation systems fed by the Ogallala Aquifer. These fields are abandoned when the aquifers dry up, resulting in erosion of the unused farmland. Conservation programs such as the Conservation Reserve Enhancement Program (CREP) were established to address this problem but have been unsuccessful in restoring native grasslands in abandoned croplands in southwestern Kansas. We hypothesized that insect …


Climate Niche Evolution In C4+Cam Portulaca And Closely Related C3+Cam Lineages, Nora M. Heaphy Jan 2021

Climate Niche Evolution In C4+Cam Portulaca And Closely Related C3+Cam Lineages, Nora M. Heaphy

Library Map Prize

With at least a hundred independent origins among land plants, the CAM and C4 photosynthetic pathways represent one of the most notable examples of global convergent evolution of a complex trait. While biochemically similar, CAM and C4 are generally understood to be two distinct ecological adaptations evolving along separate trajectories. However, the purslanes (Portulaca), a globally widespread clade of around 100 species of annual and perennial succulents, are able to operate both CAM and C4 cycles in the same leaf. Portulaca likely originated from a facultative CAM ancestor and then evolved a C4 system at least three times …


Religious Naturalisms, Carol W. White Jan 2021

Religious Naturalisms, Carol W. White

Other Faculty Research and Publications

This article focuses on recent developments in religious naturalism in the twenty-first century, building on Jerome Stone’s 2008 study of its resurgence in the mid-twentieth century. I introduce religious naturalism as a synthesis of naturalistic ideas that often depart from traditional forms of religious thinking, defining it as a capacious, ecological religious worldview grounded in the observational conviction that nature is ultimate. I also describe different models of religious naturalism, focusing on the key ideas found in the influential publications of contemporary religious naturalists (e.g., Ursula Goodenough, Donald Crosby, Loyal Rue, among others). While acknowledging specific points of emphasis, I …


Swimming Against The Flow: Environmental Dna Can Detect Bull Sharks (Carcharhinus Leucas) Across A Dynamic Deltaic Interface, James Marcus Drymon, Katherine E. Schweiss, Emily A. Seubert, Ryan N. Lehman, Toby S. Daly-Engel, Mariah Pfleger, Nicole M. Phillips Jan 2021

Swimming Against The Flow: Environmental Dna Can Detect Bull Sharks (Carcharhinus Leucas) Across A Dynamic Deltaic Interface, James Marcus Drymon, Katherine E. Schweiss, Emily A. Seubert, Ryan N. Lehman, Toby S. Daly-Engel, Mariah Pfleger, Nicole M. Phillips

Faculty Publications

© 2020 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd Human activities in coastal areas are accelerating ecosystem changes at an unprecedented pace, resulting in habitat loss, hydrological modifications, and predatory species declines. Understanding how these changes potentially cascade across marine and freshwater ecosystems requires knowing how mobile euryhaline species link these seemingly disparate systems. As upper trophic level predators, bull sharks (Carcharhinus leucas) play a crucial role in marine and freshwater ecosystem health. Telemetry studies in Mobile Bay, Alabama, suggest that bull sharks extensively use the northern portions of the bay, an estuarine–freshwater interface known …


Functional Genetic Approaches To Provide Evidence For The Role Of Toolkit Genes In The Evolution Of Complex Color Patterns In Drosophila Guttifera, Mujeeb Olushola Shittu Jan 2021

Functional Genetic Approaches To Provide Evidence For The Role Of Toolkit Genes In The Evolution Of Complex Color Patterns In Drosophila Guttifera, Mujeeb Olushola Shittu

Dissertations, Master's Theses and Master's Reports

Toolkit genes are set of genes that orchestrate the development of basic body plan of animals, and they are highly conserved in all animals. The co-option of the toolkit genes into the pigmentation pathway has led to the evolution of novel species. This study focuses on understanding how the complex color patterns in animals develop by using the Drosophila species in the quinaria group as models. We developed an mRNA in situ hybridization (ISH) protocol, which allowed us to study gene expression patterns in the abdomen of developing pupae of non-model Drosophila species (Chapter 2). Through ISH, we found that …


Controls On Autotrophic Respiration, Heterotrophic Respiration, And Decomposition In Northern Forested Rivers, Renn Schipper Jan 2021

Controls On Autotrophic Respiration, Heterotrophic Respiration, And Decomposition In Northern Forested Rivers, Renn Schipper

Dissertations, Master's Theses and Master's Reports

Autotrophic respiration (AR), heterotrophic respiration (HR), and decomposition are important contributors to the carbon cycle in streams. It is important to understand how different environmental factors, such as canopy cover and dissolved organic carbon (DOC), influence these processes. DOC concentrations in northern forested streams are increasing, which may affect light and carbon availability. To examine the effects of DOC and canopy cover on these processes we measured gross primary production, ecosystem respiration and decomposition at 8 sites in 4 streams in the Upper Peninsula of Michigan and used quantile regression to estimate AR and HR. Among sites, AR and decomposition …


Metagenomic Identification And Classification Of The Mercury-Methylating Gene Hgca In Response To Water Table And Plant Functional Group Manipulations In Peat Soil, Madeline Peterson Jan 2021

Metagenomic Identification And Classification Of The Mercury-Methylating Gene Hgca In Response To Water Table And Plant Functional Group Manipulations In Peat Soil, Madeline Peterson

Dissertations, Master's Theses and Master's Reports

Methyl-mercury (MeHg) is a potent neurotoxin that threatens the health of humans and wildlife alike. Climate warming threatens to shift regional precipitation and climate regimes in peatland environments, which could destabilize northern peatlands and accelerate both Hg release from soil and MeHg production. Peatlands are among the leading hotspots for MeHg, yet little is known about the community composition or functional relationship of mercury-methylating microbes in response to varying environmental conditions. The recognized mercury-methylating genes responsible for this activity are the obligatory gene pair hgcA and hgcB. Metagenomic data from the full-factorial peatland mesocosm experiment PEATcosm was obtained to …


Regional Impacts Of Invasive Species And Climate Change On Black Ash Wetlands, Joseph Shannon Jan 2021

Regional Impacts Of Invasive Species And Climate Change On Black Ash Wetlands, Joseph Shannon

Dissertations, Master's Theses and Master's Reports

For more than a decade intensive research on the ecohydrology of black ash wetland ecosystems has been performed to understand these systems before they are drastically altered by the invasive species, emerald ash borer (EAB). In that time there has been little research aimed at the scale and persistence of the alterations. Three distinct but related research articles will be presented to demonstrate a method for moderate resolution mapping of black ash across its entire range, understand the relative impacts of EAB and climate change on probable future wetland conditions, and develop an experimental and modeling approach to quantify and …


Denitrification And Nitrogen Fixation Commonly Co-Occur But Rates Vary Throughout The Year And In Different Environments, Kevin Nevorski Jan 2021

Denitrification And Nitrogen Fixation Commonly Co-Occur But Rates Vary Throughout The Year And In Different Environments, Kevin Nevorski

Dissertations, Master's Theses and Master's Reports

Denitrification and nitrogen fixation are nitrogen cycling processes that can occur simultaneously in streams but are rarely studied together. The overarching goal of this dissertation was to quantify temporal and spatial variation of these processes in streams across the USA, characterize the environmental drivers of that variation, and determine the role that denitrification plays in the carbon cycle. To characterize temporal variation in these processes, a 2-year study in the Pilgrim River in Michigan’s Upper Peninsula found no difference in rates among seasons but high day-to-day variation in rates of both processes (maximum daily change 4,390 μg N/m2/hr …


Cost Of Co-Infection In Peromyscus Leucopus Mice, Ananya Sagar Jan 2021

Cost Of Co-Infection In Peromyscus Leucopus Mice, Ananya Sagar

Scripps Senior Theses

Abstract

Co-infections occur frequently across humans & wildlife, and can have effects on host health. Despite the prevalence of microparasite-helminth co-infections, majority of the research focuses either on singular infections or on concurrent infections in a laboratory setting. This fails to take into account the interspecific interactions between the multiple parasites and the host in natural settings. The interactions could be direct by resource competition, or indirect via the host immune system. In our research, we studied the relationship between nematodes and coccidia in their host, Peromyscus leucopus mice, at the Mountain Lake Biological Station, Virginia. We further evaluated the …


Timing Of Predation Risk During Early Development Influences Oyster Shell Morphology, Armorel Eason, Andrew B. Powell, Sarah H. Roney, Carter Lin, Christa M. Russell, Benjamin A. Belgrad, Delbert Lee Smee Jan 2021

Timing Of Predation Risk During Early Development Influences Oyster Shell Morphology, Armorel Eason, Andrew B. Powell, Sarah H. Roney, Carter Lin, Christa M. Russell, Benjamin A. Belgrad, Delbert Lee Smee

Gulf and Caribbean Research

No abstract provided.


Importance Of Instream Habitat To Recruitment And Community Structure Of Aquatic Invertebrates, Catherine R. Billé Jan 2021

Importance Of Instream Habitat To Recruitment And Community Structure Of Aquatic Invertebrates, Catherine R. Billé

Master’s Theses

This thesis investigates how mechanisms of colonization by aquatic insects, both by ovipositing adults and or larval drift, operate at either micro-, meso-, or macro-scales to influence larval community assemblage in streams. Our study took place in a forested floodplain stream characterized by uniform soft clay and loose detritus substrate. Within this study reach we built three sets of riffles, with each set comprised of three identical riffles built either 15, 10, or 5 m apart. We examined microscale influences on community assemblage by studying recruitment of egg masses to our constructed riffles. We found that riffle habitat additions were …


Alfred Russel Wallace Notes 15. Wallace's Many "Hats": What Should We Call Him?, Charles H. Smith Jan 2021

Alfred Russel Wallace Notes 15. Wallace's Many "Hats": What Should We Call Him?, Charles H. Smith

Faculty/Staff Personal Papers

Alfred Russel Wallace (1823−1913) has been referred to by name through the aid of a variety of labels – some thirty or more, in fact – that link him to his emphases of attention. How many of these labels are/were justifiable? The assessment here is that he is probably best remembered as a ‘naturalist,’ ‘geographer,’ ‘evolutionist,’ and ‘social critic.’


An Enumeration Of Nested Networks, Nathan Cornelius Jan 2021

An Enumeration Of Nested Networks, Nathan Cornelius

Williams Honors College, Honors Research Projects

Nested networks have several applications in phylogenetics and electrical circuit theory. In many cases, there may exist more than one distinct network which correctly models a given data set. This proposes a combinatorial problem to determine all possible network solutions. In this paper, we partially solve this problem by developing exponential generating functions which enumerate all 1-nested and 2-nested unicyclic networks. We also describe our procedure to directly count all 1-nested and 2-nested networks and provide all 1-nested networks with 7, 8, and 9 terminal nodes.