Evolution Commons^™

A Literature Review Of Horn And Horn-Like Structures In Vertebrates To Correlate Placement To Function, Behavior, And Niche., J T. Cottingham

Biology Papers and Presentations

In this paper, the true horns of bovids are compared to the many horn-like structures found throughout the animal kingdom. Literary sources were reviewed for a variety of horn-like structures. The review was limited to extinct and extant terrestrial vertebrates. 3D models of these organisms' skulls and “horns” were created or acquired and 3D printed at the same scale to illustrate their differences and similarities and to analysis of their comparative size easier between large and small genera.

Adaptive Tolerance To Sodium Chloride In Daphnia Magna, Brady P. Parlato, Rick Kopp

Kentucky Journal of Undergraduate Scholarship

Salinity levels of some freshwater systems have been altered by humans, posing a threat to aquatic life. We hypothesized that a Daphnia magna population pre-treated with a low concentration of NaCl would develop greater salinity tolerance than an untreated population. Two Daphnia magna cultures with 60 individuals each were established, one started with 1.00 ppt NaCl and increased by 0.20 ppt weekly, and the other with pure spring water. After 4 weeks, 40 neonates from each culture were individually placed in a solution of 2.30 ppt NaCl (separately determined to be the LC₅₀) for 48 hours. Survival was …

Development Of A Novel Cardiac Ischemia-Reperfusion Model In The Axolotl, Jeremy Tolentino Llaniguez

Wayne State University Dissertations

The Center for Disease Control’s National Center for Health Statistics data for mortality from diseases of the heart show the age-adjusted death rate has fallen from almost 600 deaths in the 1950s to just over 190 deaths per 100,000 U.S. residents today. With the recognized limitations of pharmacotherapy of myocardial infarction (MI), cell-based therapies have been undergoing rapid development and clinical testing. However, there is still no consensus about cell types, delivery routes, dosing and treatment schedules and pretreatment conditioning of cells prior to administration. Furthermore, a fundamental question remains unanswered about the reasons for the poor capacity for myocardial …

Ashfall Fossil Beds: From Waterhole To Rhino Barn, Sandy Mosel

University of Nebraska State Museum: Programs Information

Twelve million years ago a volcanic super-eruption in what is now southwestern Idaho created an enormous ashfall that blanketed the Great Plains with several inches of volcanic ash, devastating the local wildlife. Evidence of this geologic event lies within the hills of the Niobrara River Valley in northeast Nebraska, at a place aptly named the Ashfall Fossil Beds State Historical Park. Located near the tiny village of Royal, the Ashfall Park has been developed around a waterhole where animals succumbed after breathing in the volcanic dust. Buried deeply by windblown volcanic ash in the weeks following the eruption, the skeletons …

Temperate Eurasian Origins Of Hawaiian Chenopodium (Amaranthaceae) Plus Description Of A New Species Endemic To Moloka‘I, Jason T. Cantley, Angela J. Mcdonnell, J Branson, S R. Long, W Garnett, Christopher T. Martine

Faculty Journal Articles

Chenopodium taxa of Hawai‘i are tetraploids distinguished from other members of the circumglobally distributed genus by minute morphological characters. Because of these reasons, the geographic origin of Hawaiian Chenopodium has remained unclear. Across the Hawaiian Archipelago, Chenopodium taxa are morphologically variable and grow in highly disparate xeric habitats, especially in terms of precipitation, temperature, wind, salt spray, and solar irradiation. Habitats include dry subalpine shrublands, sandy beach strand of atolls in the Northwest Hawaiian Islands, dry forests, and precipitously tall sea cliffs of northwestern Moloka‘i. From the Moloka‘i sea cliffs, which are battered by high energy winds, salt spray, and …

The Origin And Evolution Of Flower Characters In Angiosperms With A Case Study On The Genetic Basis Of Zygomorphic Corolla Development In Bee And Hummingbird Pollinated Species Of Schizanthus (Solanaceae), Ghadeer Bukhari

Theses and Dissertations

This Ph.D. dissertation investigates two main projects separated into two chapters, one for each. The first chapter explores the evolution of flowering plants (angiosperms), a macro-scale study. The second project is on a micro-scale that focus on exploring the genes that regulate the similarities and the differences of flower morphology reflecting their different pollination syndromes in two species of Schizanthus (Solanaceae), i.e., S. pinnatus, a bee-pollinated flower, and S. grahamii, a hummingbird- pollinated flower.

In the first chapter, I used floral diagrams to study the origin and the evolution of floral traits in angiosperms, a new set of morphological data …

Evolutionary Ecology Of The Native Johnny Darter (Etheostoma Nigrum) And The Invasive Round Goby (Neogobius Melanostomus): A Genomic Perspective, Abby Joyce Wicks

Wayne State University Dissertations

Round goby (Neogobius melanostomus) is an invasive fish present in all five Great Lakes and is becoming increasingly common in their tributaries. Johnny darter (Etheostoma nigrum) is a native species that often coexists with round goby. Here, I use traditional population genetic methods and genomic tools to explore the evolutionary ecology of these species. First, historic factors are addressed as a source of variation in study populations by characterizing patterns of mitochondrial DNA variation throughout Lower Michigan. Round goby populations were largely homogenous and exhibited no evidence of overarching historical genetic structure, consistent with the recent invasion and rapid expansion …

Molecular Mechanisms Shaping Host Range Of A Vector-Borne Pathogen, Thomas Macgregor Hart

Legacy Theses & Dissertations (2009 - 2024)

Vector-borne diseases, such as Lyme disease caused by Borrelia burgdorferi sensu lato (Bbsl), have narrow host ranges and are apt models to study host-microparasite coevolution. Some species and strains of Lyme borreliae (LB) are specialists, infecting only mammalian or only avian hosts (ex. Borrelia afzelii and B. garinii, respectively), while others are generalists and infect both hosts (ex. B. burgdorferi). Such host tropisms are hypothesized to be partially shaped by the ability of these pathogens evade host immune defenses, such as complement. Complement is a first line host defense against invading pathogens that kills LB in vitro and inhibits spirochete …

Asian Elephant Rescue, Rehabilitation And Rewilding, Liv Baker, Rebecca Winkler

Animal Sentience

Thailand has fewer than 10,000 elephants left. More of them are living in captivity to serve the tourist industry under grim conditions than are living free in what is left of their wild habitat. Conservation efforts need to be focused on all surviving members of the species, captive and free, but they need to take into account the inextricable entanglement of human and nonhuman animal lives in Thailand today. There is an opportunity for rescuing, rehabilitating and reintroducing captive elephants to the wild with the help of the traditional expertise of a mahout culture that has been elephant-keeping for centuries. …

Rewilding And Domestication: Clarifying Terminology, Catia Correia-Caeiro

Animal Sentience

Baker & Winkler (B&W) describe the state of Asian elephant conservation, raising unique issues, and proposing a direction based on rewilding. The long history and socio-biology of elephants and humans has some parallels with the domestication of dogs (and other species). However, markers of domestication seem absent from elephants. The proper use of terms such as “wild” and “domestic” is crucial in defining the best conservation strategies, and, more important, in attending to the welfare needs of individuals, which can differ between wild and domestic animals. B&W’s target article represents an important starting point for discussion around elephant conservation, but …

Innovation In Meat Production: A Problem And An Opportunity, Christopher J. Bryant

Animal Sentience

Innovation in meat production has enabled modern humans to inflict far greater harm on animals, the environment, and public health than was possible just a few decades ago. Wiebers & Feigin aptly express the urgency with which these issues must be addressed. Those advocating for animals on moral grounds face resistance from omnivores citing taste, price and convenience. Further innovation in meat production (plant-based and cultured meat) will enable us to preserve the experience of eating meat whilst phasing out the many problems caused by industrial animal farming.

Harm, Earth Jurisprudence And Human/Nonhuman Relationships, Tanya Wyatt

Animal Sentience

To prevent the next pandemic and to protect the environment and non-human animals, there needs to be a clear definition of harm and a legal system grounded in Earth Jurisprudence. Drawing on evolutionary principles to redefine harm and to radically alter the legal system to be Earth-centred will help ensure that harmful actions like certain wildlife trade, wildlife trafficking, and intensive farming do not threaten the survival of any life.

Covid-19, Evolution, Brains And Psychology, Frederick Toates

Animal Sentience

Attention needs to be directed to the processes that control behavior in humans and the adaptive problems that they solved in our early evolutionary environment. The evolutionary mismatch between the current environment and the human brain can yield important insights into the problems that beset us in the context of environmental degradation and nonhuman animal welfare.

Re-Engage With The World For Global Health And Animal Welfare, Bradley J. Bergstrom

Animal Sentience

Wiebers & Feigin (2020) make a strong argument for measures that would limit future zoonoses, such as the COVID-19 pandemic, by closing live-animal markets, changing our habits of food consumption and production, and reducing habitat destruction. These would help human health, animal welfare, and conservation of at-risk wildlife all at the same time. China’s command-and-control government can accomplish some of these things by edict, but slower-to-act western democracies play a surprisingly large role in these global problems by the power of their consumerism, including the illicit wildlife trade. We citizens need to insist that our government use all of its …

Thinking Longer, Looking Deeper, Ronnie Z. Hawkins

Animal Sentience

We need to situate the present crisis within the larger context of what we humans have done to the nonhuman forms of life with which we evolved, taking a longer view of our own evolutionary origins and a deeper look at what might be a more appropriate role for our species to play within the Biosphere.

Bridging The Empathy Gap For Invertebrates, John M. Marzluff

Animal Sentience

The actions of sentient vertebrates command our attention and inform our morality. Mikhalevich & Powell (2020) (M&P) argue that similar activities in a wide range of invertebrates with central nervous systems should do likewise. However, humans most readily empathize with creatures we recognize as similar in behavior, physiology, or appearance to ourselves. Helping humanity overcome this bias is a significant challenge for those who study invertebrates. Until this empathy gap is bridged, I believe few people and the policies they craft will afford invertebrates the moral standing that M&P argue they deserve. Therefore, I suggest those interested in raising appreciation …

Affective Sentience And Moral Protection, Russell Powell, Irina Mikhalevich

Animal Sentience

We have structured our response according to five questions arising from the commentaries: (i) What is sentience? (ii) Is sentience a necessary or sufficient condition for moral standing? (iii) What methods should guide comparative cognitive research in general, and specifically in studying invertebrates? (iv) How should we balance scientific uncertainty and moral risk? (v) What practical strategies can help reduce biases and morally dismissive attitudes toward invertebrates?

Sentience In Evolutionary Context, Jon Mallatt, Todd E. Feinberg

Animal Sentience

We appreciate the goals of Mikhalevich & Powell (M&P) and largely agree with their conclusions but we differ on some of their definitions and terms. Affects (emotional feelings) should be part of sentience. Although the evidence presented for insect sentience is strong, we list some of the counterevidence that should be considered. Our own research supports M&P’s choice of arthropods, cephalopods, and vertebrates as the only sentient organisms with moral status.

Relationship Between Cognition And Moral Status Needs Overhaul, Carrie Figdor

Animal Sentience

I commend Mikhalevich & Powell for extending the discussion of cognition and its relation to moral status with their well researched and argued target article on invertebrate cognition. I have two small criticisms: that the scala naturae still retains its appeal to some in biology as well as psychology, and that drawing the line at invertebrates requires a bit more defense given the larger comparative cognitive-scientific context.

Insect Sentience And The Rise Of A New Inclusive Ethics, David Baracchi, Luigi Baciadonna

Animal Sentience

Welfare protections for vertebrates are grounded in the belief that vertebrates are sentient and capable of feeling whereas invertebrates are not. We agree with Mikhalevich & Powell that the exclusion of small-brained invertebrates from bioethics is not warranted by the current state of the scientific evidence. The choice to promote protection for certain invertebrates should be based on the Animal Sentience Precautionary Principle (ASPP). This principle should not prevent us from conducting experimental research with non-human animals to advance knowledge. However, we believe that it is important to outline practical guidelines to manage the wellbeing of invertebrates, while accumulating further …

An Assessment Of Convergence In The Feeding Morphology Of Xiphactinus Audax And Megalops Atlanticus Using Landmark-Based Geometric Morphometrics, Edward Chase Shelburne

Master's Theses or Doctor of Nursing Practice

Convergence is an evolutionary phenomenon wherein distantly related organisms independently develop features or functional adaptations to overcome similar environmental constraints. Historically, convergence among organisms has been speculated or asserted with little rigorous or quantitative investigation. More recent advancements in systematics has allowed for the detection and study of convergence in a phylogenetic context, but this does little to elucidate convergent anatomical features in extinct taxa with poorly understood evolutionary histories. The purpose of this study is to investigate one potentially convergent system—the feeding structure of Xiphactinus audax (Teleostei: Ichthyodectiformes) and Megalops atlanticus (Teleostei: Elopiformes)—using a comparative anatomical approach to assess …

Landscape Ecology And Population Genomics Of Two Sympatric Pitviper Species Across A Fragmented Appalachian Landscape, Thomas Maigret

Theses and Dissertations--Biology

Understanding the link between landscape patterns and ecological and evolutionary processes is an important prerequisite for informed wildlife conservation and management, especially in rapidly changing landscapes. Until recently, the inaccessibility of spatial and genomic data sets of sufficient resolution limited our ability to incorporate the impacts of landscape patterns into predictions of ecological and environmental outcomes. In this dissertation, I utilized several high-resolution spatial and genomic data sets to address ecological questions in a rapidly fragmenting landscape in southeastern Kentucky. Overall, my results indicate that large-scale surface coal mining is causing widespread homogenization of landforms, resulting in a uniquely permanent …

Predicting Patterns Of Gene Family Evolution In Taxa With Similar Ecological Niches, Kim Vertacnik

Theses and Dissertations--Biology

To fully understand the genetic basis of adaptation, we need to know its predictability—the extent to which specific selective pressures and contexts can yield corresponding genetic changes. In particular, the repeated colonization of similar, specialized environments by different taxa is ideal for assessing the frequency of reoccurring changes in the same genes or functions. But compared to a growing body of literature on the convergent evolution of individual genes, far less is known about the repeatability of gene family evolution, where families (defined here as groups of genes that share sequence and functional similarity from common ancestry) can expand (gain …

Limb Development In Salamanders: An Evolutionary Perspective To The Tetrapod Limb, Sruthi Purushothaman

Theses and Dissertations--Biology

Vertebrate limb is an ideal model to study growth, patterning and morphogenesis and the interplay between these processes. The developing limb bud is a three-dimensional structure and its outgrowth depends on the interaction between 2 important signaling centers: the Apical Ectodermal Ridge (AER) at the junction of the dorsal and ventral halves of the limb bud and the Zone of Polarizing activity (ZPA) in the posterior mesenchyme. These centers produce their respective key molecules and the close interplay between them specifies structures along the anterior-posterior (thumb to pinky), proximal-distal (shoulder to fingertips) and dorsal-ventral (knuckle to palm) axes.

Developmental biologists …

Identification Of Odorant Receptor Genes In The Antennal Transcriptome Of The Common Eastern Fireflies, Photinus Pyralis, Hanh Tran

Honors Theses

The insect odorant receptor, OR, gene family has been hypothesized to play a critical role in reproduction. Odorant receptor proteins, located on the olfactory sensory neuronal dendrites, detect odorant chemicals such as pheromones and then mediate key behaviors such as mate choice. Although olfaction is known to play a predominant role in sexual communication, there are still large numbers of olfactory genes that have not been studied in many insect species including fireflies. In this study, I investigated the sequencing data of one of the common eastern fireflies, Photinus pyralis (Coleoptera: Lampyridae). This firefly species is well known for their …

Appealing To Human Intuitions To Reduce Animal Abuse, Yzar S. Wehbe, Todd K. Shackelford

Animal Sentience

Social scientists may be able to find ways to positively affect people’s evolved moral compasses, thereby doing the planet and its inhabitants a great kindness. They could help to shape a constituency that is increasingly opposed to animal abuse in its largest-scale manifestations, factory farming and wet markets. This would, in turn, motivate people to elect ethical leaders who view inaction with regard to animal abuse as a serious moral and medical mistake, if only indirectly due to factory farming’s exacerbation of the threats zoonoses pose to humans.

The Host Gatekeeper: Using The Flagellar Pathway To Understand Symbiont Host Adaptation, Adam R. Pollio

Graduate Theses, Dissertations, and Problem Reports (ETD)

The acquisition of microbial partners is a strategy used by a diverse group of arthropods to overcome ecological barriers that might normally make certain niches uninhabitable. The unique phylogenetic opportunities attainable from the natural experiment of the Sodalis-allied clade allow for better understanding of how molecular structures evolve through time. Here, we focus on the evolution of the flagellar synthesis pathway, due to its complexity and ability to diverge in response to ecological pressures. We used this molecular pathway and natural experiment to show that normal evolutionary outcomes associated with symbiosis (i.e., genome reduction) do not explain the predicted conservation …

Trees, Fungi, Insects: How Host Plant Genetics Builds A Community, Sandra Jeanne Simon

Graduate Theses, Dissertations, and Problem Reports (ETD)

Organisms, such as fungi and insects, can cause millions of acres of agricultural and forest damage, while others provide billions of dollars in ecological services such as education, aesthetic enjoyment, pollination, and gardening. Plant breeding and biotechnology can potentially help establish a balance between the proliferation of detrimental pests and attraction of beneficial insects. Variation in plant physiological and morphological characteristics are extremely important in the ability of host tissues to support many different types of organisms. When that variation is genetically heritable in a plant population, shifts in the underlying genes can have predictable consequences in structuring entire ecosystems. …

Developmental Mechanisms For The Diversification Of Polyphenic Morphs In The Head Horn Of Onthophagine Beetles (Coleoptera: Scarabaeidae Onthophagus Taurus): Plasticity Through Nutrition, Logan Paul Zeigler

Graduate Theses, Dissertations, and Problem Reports (ETD)

Developmental plasticity is the phenotypic variation between organisms that is caused by environmental interactions affecting the developmental systems of organisms. The research focused primarily on nutrition-responsive developmental plasticity. In this research we used the nutritionally determined head horn development of Onthophagus taurus to better understand the developmental mechanisms and genetic underpinnings of nutrition-responsive trait development. We focused specifically on altering the availability of specific nutrition-related primary metabolites, cholesterol and palmitic acid, identified in the activity of The Hedgehog pathway, a critical pathway in head horn development. By altering diet composition using cholesterol, reducing transcript expression of an acyltransferase gene, rasp …

The Effects Of Internal Physiology On Polyphenic Horn Development In The Dung Beetle Onthophagus Taurus, Naomi Garrett Williamson

Graduate Theses, Dissertations, and Problem Reports (ETD)

An organism’s phenotype can be affected in development by alterations to gene expression based on environmental inputs. Nutrition is one such environmental input and the central regulator of development of large horn or small horn phenotypes in the dung beetle species, Onthophagus taurus. However, little is known about the nature of chemical compounds that are critical to this plastic horn development. To better understand these compounds, we are utilizing an untargeted metabolomic approach as well as a targeted gene approach. Through the metabolomic approach, it was uncovered that environmental conditions tend to have a greater impact on metabolomic composition …