Digital Commons Network^™

Extended Scaffolding: A More General Theory Of Scaffolded Cognition, Zachary R. Murphy

Open Access Theses

New and emerging technologies called neuroprostheses are challenging our ideas about where one's mind ends and the environment begins. Cochlear implants, which completely replace the functioning of the inner ear, are now a common treatment for deafness. Berger et al. developed a device that replaces long-term memory in rats (2012), while Hampson et al. created a brain-machine interface that converts a desire to move one's arm into the motor neuron impulses required to achieve that movement (2013)--both offering promising treatments for dementia, Alzheimer's disease, and paralysis. Deep brain stimulation is now a common way of regulating neural activity to manage …

Use Of Plastic Bottles As An Alternative Container Type For Propagation Of Forest Tree Seedlings In Restoration Programs, Safiullah Khurram

Open Access Theses

Deforestation and forest degradation is a global issue, especially in poor and developing regions of the world. In order to combat deforestation it is critical to enhance the productivity of forest restoration operations, which often involve planting of nursery-grown forest tree seedlings. Production of low quality stock types with deformed and spiraled root systems is a significant issue hindering successful restoration programs. Polybags (i.e., small plastic bags) are a common container type for seedling propagation in developing countries. However, polybags produce seedlings with spiraled and deformed root systems that reduce outplanting survival and performance. Use of discarded plastic water bottles …

Effects Of Temperature And Pollinator Availability On Plant Reproductive Success In The Indiana Spring Ephemeral Community, Asya Robertshaw

Open Access Dissertations

Temperature is a key driver of phenology in both plants and insects, and even small changes in temperature can impact the reproductive success of insect-pollinated plants by influencing access to pollinator services. While it is well-established that temperature variation directly impacts the flowering phenology of many plant species, the mechanisms by which it ultimately influences seed production via the pollinator community are not well understood. Climate change has the potential to disrupt the temporal synchrony between plants and their primary pollinators, especially if the two rely on different seasonal cues for the timing of their life history events. If the …

Undercover Predators: Vegetation Mediates Foraging, Trophic Cascades, And Biological Control By Omnivorous Weed Seed Predators, Carmen K Blubaugh

Open Access Dissertations

Weed pressure is the most costly challenge that vegetable growers face, requiring more labor investment than other production inputs. Vertebrate and invertebrate seed predators destroy a large percentage of weed propagules on the soil surface, and their ecosystem services may ease labor requirements for farmers in herbicide-free systems. Cover provided by living vegetation is an important predictor of seed predator activity, and my dissertation takes a comprehensive approach to understanding the behavior, predator, and environment-mediated mechanisms by which cover impacts weed seed predation in crop environments. ^ First, I performed a meta-analysis of 27 studies to quantitatively evaluate what is …

Biology And Ecology Of Bigheaded Carp In An Invaded Ecosystem, Alison Adele Coulter

Open Access Dissertations

Globally, the homogenization of species has become a threat to biodiversity. As species are transported around the world, a portion of these species, released intentionally or accidentally, may become invasive and can produce negative impacts. Great effort has been invested into early identification and prevention of invasions as these are considered less expensive than managing an invasion. Unfortunately, species may exhibit varying characteristics across ecosystems, and so their behavior and potential survival in a new environment may be difficult to predict. Therefore, I examined trends in the biology and behavior of invasive fishes, including the plasticity surrounding these and how …

Consequences Of Short-Term Water Temperature Variability To Fish: Current And Future Climate Change Impacts, David P. Coulter

Open Access Dissertations

Water temperature has a profound influence on aquatic ectotherms by affecting all aspects of biological organization; from chemical and molecular functioning to whole-organism and population-level impacts. Natural processes and anthropogenic activities can create conditions where temperatures vary greatly through space and time. While exposure to temperature changes lasting ≥ 24 hours have been examined in some species, it is unclear how more rapid (< 24 hours; sub-daily) thermal fluctuations affect aquatic ectotherms. I used a combination of field observations, laboratory experiments, and modeling simulations to understand: 1) how habitat quality of aquatic ectotherms is affected in thermally dynamic environments; 2) the role of sub-daily temperature fluctuations on growth, survival, and stress responses in juvenile and adult fish; 3) how fish early life stages are affected by sub-daily temperature fluctuations; and 4) what impact thermally dynamic environments have on a model species at a population-level. A model quantifying habitat quality around power plant thermal discharges indicated that elevated and variable discharge temperatures affected habitat quality over a relatively small spatial area for aquatic ectotherms. Models examining elevated temperatures representing climate warming showed that the effects of industrial discharges and climate warming could have an interactive effect on habitat quality by increasing the spatial area and duration over which industrial thermal effluents impact aquatic ectotherms. Laboratory experiments indicated that closely related fishes can respond differently to the same sub-daily temperature fluctuations. Yellow perch (Perca flavescens) had higher consumption and growth under sub-daily temperature fluctuations but developed skin lesions; an indication of thermal stress. In contrast, these same fluctuations reduced growth in physiologically similar walleye (Sander vitreus) …

Carrion-Associated Arthropods In Rural And Urban Environments, Serena Daye Gross

Open Access Dissertations

Preferences of arthropods are important in forensic entomology, as the species collected can help determine the postmortem interval or if remains have been moved. This study looked at arthropods that are attracted to pig carcasses in rural and urban habitats in Northwest Indiana. The species and number of carrion-associated arthropods that are found at a carcass vary with habitat type, month, and stage of decomposition. Lucilia sericata (Diptera: Calliphoridae) is a synanthropic species that was found in higher numbers in urban locations for both adults and larvae. Though L. sericata had higher numbers in urban habitats, caution must be exercised …

Concurrent Coevolution Of Intra-Organismal Cheaters And Resisters, S R. Levin, D A. Brock, David C. Queller, Joan E. Strassmann

Biology Faculty Research

The evolution of multicellularity is a major transition that is not yet fully understood. Specifically, we do not know whether there are any mechanisms by which multicellularity can be maintained without a single-cell bottleneck or other relatedness-enhancing mechanisms. Under low relatedness, cheaters can evolve that benefit from the altruistic behaviour of others without themselves sacrificing. If these are obligate cheaters, incapable of cooperating, their spread can lead to the demise of multicellularity. One possibility, however, is that cooperators can evolve resistance to cheaters. We tested this idea in a facultatively multicellular social amoeba, Dictyostelium discoideum. This amoeba usually exists as …

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

Undergraduate Research Symposium 2015

Brachiopods are small animals that live on the seafloor and are prominent in the Devonian fossil record from 420 to 360 million years ago. An interesting feature of some species is that large spines develop on their exterior surfaces and are thought to have evolved for defense against predators. Fortunately, this hypothesis can be tested by observing wound marks indicative of attempted predation as described by Zhang et al. (2011). In this study, I examined wound marks on fossils of the spiny brachiopod Atrypa rockfordensis and the spineless Atrypa devoniana. Results show that A. rockfordensis only experienced attacks at …

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

Biological Sciences Grants Collections

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

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

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

• Linked Syllabus
• Initial Proposal
• Final Report

A Comparison Of The Genetic Diversity Of The Class Ii Major Histocompatibility Complex In Ex Situ And In Situ Populations Of African Penguins (Spheniscus Demersus), Emily Willmer

Undergraduate Honors Thesis Projects

As an endangered species, the African penguin (Spheniscus demersus) is at risk of becoming extinct in the wild due to destruction of their coastal habitat and reduction in food availability. The development of a genetically diverse and healthy captive population is important in helping to conserve the species. The goal of this project was to determine the genetic diversity of the class II major histocompatibility complex (MHC) of a wild population of African penguins and compare it to the diversity of the captive population at Mystic Aquarium in Mystic, Connecticut that has previously been studied. We found that …

Distribution And Identification Of Fish Eggs In An Internal Wave Transport Mechanism, Claire Kuelbs

Undergraduate Honors Theses

Internal waves have been proven to transport invertebrate larvae onshore, but there has been little indication on whether internal waves transport fish eggs. Fish eggs are typically buoyant and are often found in neustonic samples, and internal waves often cause fronts that transport oils and other light particles. This research aims to determine whether there are patterns to the distribution of fish eggs. One possibility is that offshore fish eggs can be transported onshore, to nearshore nursery habitats. Before 2003, when genetic barcoding was proposed as an identification mechanism, fish eggs could only be identified visually, using color, size, and …

The Ecological Significance Of Emerging Deltas In Regulated Rivers, Malia A. Volke, Michael L. Scott, W. Carter Johnson, Mark Dixon

Natural Resource Management Faculty Publications

Sedimentary deltas forming in the world’s regulated rivers are a glaring gap in our knowledge of dammed riverine ecosystems. Basic ecological information is needed to inform the current debate about whether deltas should be retained and managed to gain ecosystem services lost under reservoirs or whether they should be partially removed to improve flow conveyance and to resupply sediment-starved reaches below dams. An examination of nine deltas on the heavily regulated upper and middle Missouri River showed the following: The sizes, dynamics, and biotic communities vary widely across deltas; riparian forest has established on portions of most deltas; the current …

Harvest Demographics Of Temperate-Breeding Canada Geese In South Dakota, 1967–1995, Jeffrey S. Gleason, Jonathan A. Jenks, David E. Naugle, Paul W. Mammenga, Spencer J. Vaa, Jennifer M. Pritchett

Natural Resource Management Faculty Publications

In South Dakota, breeding giant Canada geese (Branta canadensis maxima) have increased substantially, and harvest management strategies have been implemented to maximize hunting opportunity (e.g., special early-September seasons) on local, as well as molt-migrant giant Canada geese (B. c. interior) while still protecting lesser abundant Arcticbreeding Canada geese and cackling geese (e.g., B. hutchinsii, B. minima). Information on important parameters, such as survival and recovery rates, are generally lacking for giant Canada geese in the northern Great Plains. Patterns in Canada goose band recoveries can provide insight into the distribution, chronology, and harvest pressures to which a given goose population …

Experimental Shifts In Intraclutch Egg Color Variation Do Not Affect Egg Rejection In A Host Of A Non-Egg-Mimetic Avian Brood Parasite, Rebecca Croston, Mark E. Hauber

Publications and Research

Avian brood parasites lay their eggs in the nests of other birds, and impose the costs associated with rearing parasitic young onto these hosts. Many hosts of brood parasites defend against parasitism by removing foreign eggs from the nest. In systems where parasitic eggs mimic host eggs in coloration and patterning, extensive intraclutch variation in egg appearances may impair the host’s ability to recognize and reject parasitic eggs, but experimental investigation of this effect has produced conflicting results. The cognitive mechanism by which hosts recognize parasitic eggs may vary across brood parasite hosts, and this may explain variation in experimental …

The Network Motif Architecture Of Dominance Hierarchies, Daizaburo Shizuka, David B. Mcdonald

School of Biological Sciences: Faculty Publications

The widespread existence of dominance hierarchies has been a central puzzle in social evolution, yet we lack a framework for synthesizing the vast empirical data on hierarchy structure in animal groups. We applied network motif analysis to compare the structures of dominance networks from data published over the past 80 years. Overall patterns of dominance relations, including some aspects of non-interactions, were strikingly similar across disparate group types. For example, nearly all groups exhibited high frequencies of transitive triads, whereas cycles were very rare. Moreover, pass-along triads were rare, and double-dominant triads were common in most groups. These patterns did …

Blue Carbon In Coastal Freshwater/Brackish Marshes On The Barrier Islands Of Virginia: Belowground Carbon Dynamics, Nathan M. Sedghi

Biological Sciences Theses & Dissertations

Some coastal ecosystems sequester substantially more carbon (blue carbon) than land locked systems due to high net primary production and deposition associated with oceanic influences. Most blue carbon research has focused on mangroves, seagrass beds, and salt marshes. Studies on blue carbon potential of coastal freshwater marshes are less common. Barrier islands frequently flood, with seawater reaching interior ecosystems. I examined brackish/freshwater marshes on Virginia barrier islands for possible roles as blue carbon systems. I studied four interior marshes on Hog Island, which varied in proximity to a direct overwash path and protection by a trail berm that divides northern …

Blue Carbon In Freshwater / Brackish Marshes On The Barrier Islands Of Virginia Aboveground Net Primary Productivity And Carbon Pools, Emily Caitlin Adams

Biological Sciences Theses & Dissertations

"Blue carbon" is a relatively new concept describing carbon distributed tidally and sequestered via net production within coastal ecosystems, including seagrass beds, mangrove forests, and salt-water marshes. These systems sequester carbon at least 10 times faster than terrestrial systems. Fresh to brackish wetlands that receive irregular tidal influence due to overwash and storm events have not been typically studied as blue carbon systems. My objective was to quantify carbon pools within four interdunal fresh to brackish marshes on Hog Island, Virginia to determine their blue carbon potential. Marshes 1 and 2 were farthest from the ocean, below and above a …

The Behavioral Causes Of Reproductive Skew In Cooperatively Polygynandrous Acorn Woodpeckers (Melanerpes Formicivorus), Anna C. Brownson

Biological Sciences Theses & Dissertations

Reproductive skew, the degree to which reproduction is shared among same-sex individuals in a social group, is a pattern affected by ecological conditions, sociality, cooperation, and the inter- and intrasexual behavior of individuals in complex animal societies. Transactional and compromise skew models assume that high skew is the product of dominance hierarchies among cobreeders, yet this has rarely been tested. Both model types fail to incorporate the decisions of more than two individuals, generally overlooking the effect of female behavior on male reproductive success in multi-male groups, and are ineffective at predicting skew in larger groups characterized by more than …

Climate Effects On Mammalian Body Size And Grassland Composition Inferred From Late Quaternary Grazers In The Great Plains Of North America, Tom Baldvins

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Several mammalian taxa exhibited a diminution during the Pleistocene-Holocene transition. Two hypotheses have been proposed to explain this phenomenon: (1) human hunting and (2) climate change along with its effects on grasslands. I use stable isotopes from a variety of Quaternary grazing mammals to measure grassland changes following the Last Glacial Maximum (LGM) in Nebraska and to develop a climate proxy to compare with mammalian body size. Results indicate that latest Pleistocene equids and mammoths have δ¹³C values indicative of a C₃ or mixed C₃/C₄ diet. However, Holocene bison have greatly elevated δ^{13 …}

Ecological Studies Of Wolves On Isle Royale, 2014-2015, John A. Vucetich, Rolf O. Peterson

Ecological Studies of Wolves on Isle Royale

Annual Report 2014-2015

Seagrass Deterrence To Mesograzer Herbivory: Evidence From Mesocosm Experiments And Feeding Preference Trials, Latina Steele, John F. Valentine

Biology Faculty Publications

Two laboratory experiments documented the effects of mesograzers (i.e. the gastropod Crepidula ustulatulina and the isopod Paracerceis caudata) on phenolic acid and condensed tannin production in 2 regionally abundant seagrasses—Thalassia testudinum (turtlegrass) and Halodule wrightii (shoalgrass). Subsequent paired choice experiments tested the hypothesis that phenolic acids and condensed tannins produced by these seagrasses deter mesograzer feeding. At the scale of the shoot, grazing by gastropods and isopods led to ~40 to 50% decreases in concentrations of some phenolic acids and ~20% decreases in condensed tannins in turtlegrass leaves. At a more refined spatial scale, concentrations of 2 of these compounds …

Ocean Food Systems, Barry A. Costa-Pierce

Marine Sciences Faculty Presentations

Presentation given during session on Food Justice, where Barton Seaver, Director of the Healthy and Sustainable Food Program in the T.H. Chan School of Public Health at Harvard, described a great nutrition and health crisis in America perpetuated by groups demarketing seafood and promoting meat in the American diet. Seaver noted that Americans consume about 167 lbs. of meat a year and only 14 lbs. of seafood, leading to connected public health and environmental crises, heart disease, and obesity.

According to presenter Barry Costa-Pierce:

Seafood systems in the USA are our most insane foods; America imports nearly every seafood we …

Elevational Gradients In Β-Diversity Reflect Variation In The Strength Of Local Community Assembly Mechanisms Across Spatial Scales, J Sebastián Tello, Jonathan A. Myers, Manuel J. Macia, Alfredo F. Fuentes, Leslie Cayola, Gabriel Arellano, M Isabel Loza, Vania Torrez, Maritza Cornejo, Tatiana B. Miranda, Peter M. Jørgensen

Biology Faculty Research

Despite long-standing interest in elevational-diversity gradients, little is known about the processes that cause changes in the compositional variation of communities (β-diversity) across elevations. Recent studies have suggested that β-diversity gradients are driven by variation in species pools, rather than by variation in the strength of local community assembly mechanisms such as dispersal limitation, environmental filtering, or local biotic interactions. However, tests of this hypothesis have been limited to very small spatial scales that limit inferences about how the relative importance of assembly mechanisms may change across spatial scales. Here, we test the hypothesis that scale-dependent community assembly mechanisms shape …

An Individual-Based Model Of Chaparral Vegetation Response To Frequent Wildfire, Timothy Lucas, Dayna Mann, Reanna Dona

Seaver College Research And Scholarly Achievement Symposium

In recent years, the Santa Monica Mountains (SMM) have been plagued by frequent wildfires which threaten the native chaparral species. Nonsprouting chaparral species are completely killed by a fire, but their seeds germinate in response to fire cues. Facultative sprouters both resprout after a wildfire and release seeds that germinate post-fire. This project is based on data collected since 1986 at a biological preserve adjacent to the Malibu campus of Pepperdine University with an average fire return interval of 7.5 years. We present a spatial model that simulates the growth, seed dispersal and resprouting behavior of individual shrubs that compete …

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

Biology Faculty Research

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

The Status Of Fishes In The Missouri River, Nebraska: Blue Sucker Cycleptus Elongatus, Kirk D. Steffensen, Sam Stukel, Dane A. Shuman

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

Blue Sucker Cycleptus elongatus are a large-bodied, benthic fish that are considered an indicator species for riverine health. A combination of historic commercial fishing and anthropogenic modifications to riverine habitat led to blue suckers being listed as a candidate species for the federal threatened or endangered species list in 1993. However, they were never designated a federally protected species. Locally, Blue Suckers are currently listed as a Nebraska Natural Legacy Project’s Tier 1 species but population changes and trends have not been quantified. Therefore, the objective of this paper was to evaluate the current population status of Blue Sucker in …

The Influence Of Spines And Size Refuge On Predation Of Devonian Brachiopods From The Lime Creek Formation Near Rockford, Iowa, Broc S. Kokesh

Scholarly Horizons: University of Minnesota, Morris Undergraduate Journal

Brachiopods are small invertebrates that live on the seafloor and are prominent in the fossil record from 540 to 250 million years ago. An interesting feature of some species is that large spines develop on their exterior surfaces. These spines are thought to have evolved for defense against predators, but fossils are limited in how much information they contain about how organisms interact with each other. In this study, I examined wound markings on fossils of both a spiny (Atrypa rockfordensis) and spineless (Atrypa devoniana) species of brachiopod. Results show that spiny brachiopods were less frequently …

Historical Common Names Of Great Plains Plants, With Scientific Names Index. Volume Ii: Scientific Names Index, Elaine Nowick

Zea E-Books Collection

Containing thousands of entries of both vernacular and scientific names of Great Plains plants, the literature that informs this exhaustive listing spans nearly 300 years. Author Elaine Nowick has drawn from sources as diverse as Linnaeus, Lewis and Clark, and local university extension publications to compile the gamut of practical, and often fanciful, common plant names used over the years. Each common name is accompanied by a definitive scientific name with references and authority information. Interspersed with scientifically-correct botanical line drawings, the entries are written in standard ICBN format, making this a useful volume for scholars as well as lay …

Growth Of A Deep-Water, Predatory Fish Is Influenced By The Productivity Of A Boundary Current System, Hoang Minh Nguyen, Adam N. Rountrey, Jessica J. Meeuwig, Peter G. Coulson, Ming Feng, Stephen J. Newman, Anya M. Waite, Corey B. Wakefield, Mark G. Meekan

Fisheries Research Articles

The effects of climate change on predatory fishes in deep shelf areas are difficult to predict because complex processes may govern food availability and temperature at depth. We characterised the net impact of recent environmental changes on hapuku (Polyprion oxygeneios), an apex predator found in continental slope habitats (>200 m depth) by using dendrochronology techniques to develop a multi-decadal record of growth from otoliths. Fish were sampled off temperate south-western Australia, a region strongly influenced by the Leeuwin Current, a poleward-flowing, eastern boundary current. The common variance among individual growth records was relatively low (3.4%), but the …