Life Sciences Commons^™

Changes In Ecosystem Processes And Functional Traits Over An Elevational Gradient, Tiana Issa

Honors Theses

Elevation gradients have been used to understand how climate change impacts various ecosystems processes by substituting distance across elevation with time, reflecting a previous, colder climate. To monitor the changes in soil organic carbon (SOC), plant community, and functional traits across time in the face of climate change, this study used space-for-time substitution to emulate a long-term study with elevational gradients and revisited the same gradient for nearly two decades to monitor elevational effects across time. With this research, I aim to answer the following questions: (1) How does elevation impact ecosystem processes and alpine plant traits? (2) How does …

Testing Evolutionary Conservation Of Sex Determination In Lepidoptera Using Crispr/Cas9 Gene Editing, Sophia Schroeder

Honors Theses

The mechanism of sex determination in Lepidoptera is largely unexplored, and limited to knowledge of only a few genes. Adult Lepidoptera have obvious sexually dimorphic qualities, such as their genitalia. However, significant sex determination genes are not imperative for the adult developmental stage. Knockouts of some sex determination genes (doublesex isoforms) are shown to be lethal in the embryonic and larval stages of development in several animals. However, it is unclear whether this is due to their respective impact on sex determination and sexual dimorphism, or the existence of another function, such as pleiotropy, within a particular gene. Moreover, …

Legacies Align With Colby’S Acquisition Of Allen And Benner Islands, Bob Keyes

Colby Magazine

The College creates a 500-acre island campus in Muscongus Bay

Banned But Still Toxic: Gail Carlson Serves Notice That Chemical In Ski Racers' Waxes Still Lurk At The Starting Line, Bill Donahue

Colby Magazine

We live in a chemical world, exposing ourselves all day long to scary toxins created in laboratories—to the traces of herbicide that lurk in our water, to the carcinogenic Teflon coating our cookware, and to the pesticides sprayed on our vegetables.

A New Window Into Children's Memory: Professor Of Psychology Martha Arterberry's New Study Comes With Implications For Eyewitness Testimonies, Kardelen Koldas

Colby Magazine

When children are eyewitnesses—to an incident, an accident, or a crime— does age matter? Are older kids more precise in recounting an event than the younger ones?

Rapid Response: Cat-Scan Machine And 3d Printers Vital In Covid-19, Laura Meader

Colby Magazine

Colby’s Assistant Professor of Biology Josh Martin is using his expertise and sophisticated scientific equipment to create face shields, respirator masks, and air filter cartridges for local first responders and hospitals in need of equipment that is crucial to treating patients with COVID-19.

Challenges Of Constructing Entrainment Map For Arbitrary Circadian Models, Yuxuan (Nelson) Wu

Honors Theses

The entrainment map, developed by Dr.Diekman and Dr.Bose, is claimed to be a 1-dimensional map that produces a better prediction for phase-locking than methods than the phase response curve for circadian models. In his paper, he constructs the entrainment map for the two-dimensional circadian model, the Novak-Tyson model, and the other two higher-dimensional circadian models. For this thesis, we concentrate on exploring if it is viable to construct the entrainment map for other circadian models that are not included in his paper: the Becker-Weimann model and the Relogio model. In addition, we discuss the challenges of constructing the entrainment map …

Community Interventions To The Food Insecurity Crisis Inuit Currently Face In Nunangat, Alyssia R. Getschow

Honors Theses

Inuit living in Nunangat, a northern territory in Canada, are facing unprecedented rates of food insecurity. The increasing impacts of anthropogenic climate change are rapidly changing the Arctic landscape in Nunangat, posing challenges to Inuit hunters who hunt and live completely self-sufficient off of the land. This lack of access to country foods and the impacts these conditions are having on Inuit communities are forcing Inuit to consider aid propositions from the Canadian government. Due to a long history of conflict with white settlers during the colonization of Canada, there is a feeling of distrust and cultural distaste between Canada …

Doors Pushed Open: For Devin Gibbs, College Seemed Like A Longshot--Until It Wasn't, Kardelen Koldas

Colby Magazine

Before enrolling, Devin Gibbs ’14 received an invitation from Colby. The letter offered to bring him to campus and provide accommodations so he could get a feel for the school. What it didn’t say was he had, in essence, been admitted. Gibbs, who lived in Waterville just minutes from campus, thought the letter was a scam. “I had never gotten anything for free before,” he said.

A Better Way, Gerry Boyle

Colby Magazine

Alane O’Connor ’96 studied environmental economics at Colby. Associate Professor of Statistics Liam O’Brien first studied physics and mathematics.Together the pair has combined their broad experience to produce groundbreaking research that is changing the way clinicians around the world treat pregnant and opioid-addicted women and their unborn children.

One Step At A Time: Robotics Lab Team Combines Talents In Quest For The Perfect Synthetic Tendon, Laura Meader

Colby Magazine

When Caitrin Eaton arrived at Colby a year ago, she named her new robotics lab C3PO. The name grabs students’ attention, but they’re drawn to the lab for another reason: Eaton’s cutting-edge research unites engineering and animal physiology to help robots walk more smoothly than Hollywood’s stiff-legged C-3PO robot.

Impact Of The North American Monsoon On Molt Migrant Passerines, Liuqingqing Yang

Honors Theses

Breeding, molt, and migration place considerable yearly demands on migrating passerines in North America. Due to conflicts in energy allocation, many species have evolved migration strategies that prevent temporal overlap in these processes. However, there is recent evidence that some passerines which breed in western North America migrate to intermediate stopover sites to carry out molt, conflating molt and migration. Factors influencing the evolution of such a strategy are believed to include both aridity on breeding grounds and dependable flushes of late-summer productivity in the southwestern United States and northwestern Mexico. This productivity occurs due to the brisk rainfall of …

Use Of Small Molecule Fanconi Anemia Pathway Inhibitors As Sensitizing Agents To Laromustine., Sam W. Marchant

Honors Theses

Laromustine is an experimental chemotherapeutic sulfonyl hydrazine prodrug shown in clinical trials to be effective against acute myeloid leukemia. The mechanism of action of laromustine involves interstrand crosslinking, via chloroethylation, and enzyme inhibition, caused by carbamoylation. The work described herein aims to investigate whether inhibition of the replication-dependent interstrand crosslink repair Fanconi Anemia pathway further sensitizes cells to laromustine. By measuring metabolic activity immediately after drug exposure, we find laromustine to be equally as cytotoxic towards Fanconi Anemia deficient and wild type cells. However, through clonogenic assays we show Fanconi Anemia mutations sensitize cells to laromustine’s anti-proliferative effect. Furthermore, we …

Artificial Reefs: A History, A Science, A Technology, Mairead D. Farrell

Honors Theses

Over the past 60 years, artificial reefs have expanded beyond the definition of a technology, and in turn have developed into a unique branch of marine science. To better emphasize this growth and separation, a brief history of artificial reef development and usage in chapter two shows some of the key shifts over time in this technology’s purpose and the materials used to achieve that goal. Likewise, to indicate the scientific development of artificial reefs as a branch of marine science, their usage for discovery and research is recorded in chapter three, along with the exponential increase in published scientific …

Microbiome Community And Parasitic Infections In Wild Bees, Mark G. Young

Honors Theses

The microbiome is increasingly recognized for its complex relationship with host fitness. Akin to primates and other social animals, bumblebees harbor a specific microbiome derived from social contact. The bumblebee microbiome is characteristically species poor, with just a few “core” phylotypes accounting for the majority of total abundance. Genomic analyses reveal phylogenetic congruence and adaptation of the core endosymbionts to the bumblebee gut, indicating a shared evolutionary history. Prior investigations reveal that the relative abundance of core microbes is negatively associated with infection by a trypanosome, Crithidia bombi, and that the microbiome has a mechanistic role in immunity. As …

Morphological Variance In Mouthparts And Foraging Behavior In Bumblebees, Ye Jin Lee

Honors Theses

Bumblebees (Hymenoptera: Apidae: Bombus) show an incredible degree of size variation within and between species. Individuals from the same hive may vary up to 10-fold in mass. This variation allows individuals to specialize in foraging on different flowers suited to their morphology. However, as different species have different foraging behaviors, their variation in mouthparts and scaling of mouthparts to body size may have been under different kinds of stabilizing selection as they adapted to collect nectar from flowering plants over evolutionary time. Here, we examined the scaling relationships between body size and mouthpart structures, and the variation in mouthpart shape …

Contrasting Patterns Of Nutrient Limitation In The Littoral And Pelagic Zones Of Mesotrophic Maine Lakes, Grace C. Neumiller

Honors Theses

Intense nutrient loading of nitrogen (N) and phosphorus (P) causes sudden regime shifts in freshwater ecosystems from clearwater to turbid conditions with frequent cyanobacterial blooms. Characterization of nutrient limitation patterns of primary productivity in these ecosystems is necessary for effective management of algal blooms. However, much of this research has focused on pelagic habitats. The influence of lake habitat (i.e. benthic littoral versus pelagic zones) on nutrient limitation of primary production in mesotrophic lakes is largely unknown, particularly in contrast to research on pelagic nutrient limitation in eutrophic systems. Using paired nutrient diffusing substrata and mesocosm experiments, we measured chlorophyll- …

The Quantitative Assessment Of Pond Scum: An Examination Of The Biogeochemistry Of Phosphorus Cycling In The Belgrade Lakes, Abbey M. Sykes

Honors Theses

The internal recycling phosphorus in freshwater lake bottom sediments represents a significant source of hypolimnetic phosphorus (P) release for many of Maine’s lakes. In summer months, Maine lakes often thermally stratify and the lake hypolimnion develops anoxia, leading to a reduction in redox potential at the sediment-water interface. These reducing conditions facilitate the reductive dissolution of ferric iron, and, since phosphorus is often present in freshwater lake sediments as solid FeOOH-PO₄ complexes, results in release of soluble phosphorus into the water column. Our current study presents field and laboratory data from sediment fractionation extractions designed to quantify concentrations of …

Assessing A Two-Hit Model Of Schizophrenia: Prenatal Choline Deficiency And Induced Hypofunction Of Nmda Receptors In Male And Female Long Evans Rats, Samuel Gray, Samuel W. Gray

Honors Theses

Choline is an essential dietary nutrient essential to the development and function of the central nervous system. Prenatal choline deficiency alters hippocampal development as well as acetylcholine metabolism, leading to cognitive impairments and attentional and sensory processing deficits into adulthood. MK-801 is an NMDA receptor antagonist frequently used in rodent models of neuropsychiatric conditions, particularly schizophrenia. Acutely and sub- chronically, it causes hyperlocomotion and social withdrawal. One primary goal of the present study were to investigate prenatal choline deficiency induces a biological vulnerability to the motor deficits, anhedonia, and social impairment precipitated by low-dose sub-chronic MK-801 administration in adulthood. Another …

Executive Function Deficit As A Precursor To Memory Impairments In Hapoe4 Transgenic Rats, Kaitlin Mcmanus

Honors Theses

The hApoE4 allele is one of the strongest genetic risk factors for Alzheimer’s disease (AD). It underlies amyloid-bdeposits and neurofibrillary tangles, the two hallmarks associated with AD pathology, and is subsequently associated with AD symptomology. Despite its importance, no rat animal studies to date use hApoE4 knock-ins. In addition to this deficit in the field of AD literature, the vast majority of AD studies focus on memory, even though executive function deficits may precede memory impairments in AD, and may be a predictor of AD development. Thus, the present study addressed these gaps in AD research by investigating the behavioral …

Identifying Metabolites As Markers Of Fatigue In Athletes, Christopher D. George

Honors Theses

Fatigue in athletes caused by inadequate rest and other stressors can be severely detrimental to their health, and yet there is no reliable way to measure and track fatigue. Many classical measures of fatigue like body mass and resting heart rate are not reliable ways to track the physical fatigue of an athlete because they can change with many factors. In addition, it is not known how academic stress on top of physical stress affects fatigue. Metabolomics is a relatively new area of study and tracking metabolites offers the possibility to produce biomarkers to assess fatigue. This study collected saliva …

The Impact Of Climate Change On The Migration Phenology Of New England’S Anadromous River Herring And American Shad, Charles K. Cobb

Honors Theses

Anadromous fish play important roles in food webs and nutrient cycling in both aquatic and marine ecosystems. As a result of climate change however, anadromous fish’s migration timing has begun to change, with potentially deleterious consequences to both anadromous fish, and the species that depend on them. Western coastal US studies have linked earlier anadromous fish returns to warming marine temperatures and changes in river flow regimes, but the exact temperatures thresholds that anadromous fish respond to, and the relative importance of temperatures and river flows, remain somewhat unknown. Additionally, there has been relatively little research on anadromous fish phenology …

Development And Validation Of Gene Delivery Methods For ​Crassostrea Virginica, Adrienne N. Tracy

Honors Theses

The Eastern oyster (Crassostrea virginica) is an important part of the East Coastal USA economy because aquaculture creates jobs. Sadly, the oysters are under constant threat due to increasing pollution, red tides, and diseases. Bivalves, and oysters in particular, are also becoming potential model organisms in medical research. With the sequencing of the oyster genome, scientists are focusing on deciphering the function of the predicted genes. However, the limited number of molecular and cellular tools available makes functional annotation of the genome challenging. A consistent, replicable gene delivery system needs to be developed to assess gene function and understand the …

Insects And The Evolution Of Developmental Pathways: Functional Analysis Of Genetic Sex Determination Mechanisms In Oncopeltus Fasciatus, Josefine Just

Honors Theses

Natural selection alters genetic pathways over evolutionary time. However, different pathways have been shown to maintain mutations at varying rates, leading to different levels of conservation across developmental pathways. Sex determination pathways, in particular, show vast diversity across animals despite the fundamental conservation of biological sex itself. Here, I investigated the sex determination pathway of the hemimetabolous insect, Oncopeltus fasciatus. The large milkweed bug, O. fasciatus, is part of the order Hemiptera, which provides a relevant outgroup study to other insects in which sex determination has been studied to date. I studied three sex determination genes, intersex, fruitless …

Tracking The Endangered Northern Black Racer, Coluber Constrictor Constrictor, In Maine To Determine Areas Of Conservation Importance, Josiah Johnson

Honors Theses

The Black Racer (Coluber constrictor) is a large-bodied snake species found across North America. One subspecies, the Northern Black Racer (C. constrictor constrictor) is listed as endangered in Maine because of its restricted range in York County. Racers have generally been found to prefer open habitats and ecotones, but the specific habitat preferences of racers in Maine is unknown, hindering efforts to preserve habitat for racer conservation. To address this knowledge gap, the Maine Department of Inland Fisheries and Wildlife (MDIFW) has an ongoing project tracking black racer movements in Sanford and Kennebunk, Maine, and I had the opportunity to …

African Savannah Elephant Group Size And Behavior In The Makgadikgadi Pans National Park, Botswana, Katherine S. King

Honors Theses

African savannah elephants (Loxodonta africana), the largest elephant species, influence the structure of the environment they inhabit. Elephants exhibit complex patterns of social behavior between individuals within a population. Many behavioral studies focus on interactions among individuals within a population rather than broader trends related to group size. My study seeks to understand how male African savannah elephant group size is influenced by seasonality, age, physical condition and distance to permanent water resources. I examined the interaction of these variables in two ways: (1) a literature review of elephant behavior and conservation, and (2) an analysis of male …

Finding Aid To The Collection Of Celia Thaxter Materials, Celia Thaxter, Colby College Special Collections

Finding Aids

Celia Laighton Thaxter, 1835-1894, was an American poet and prose writer. Born Celia Laighton in Portsmouth, N.H., she spent her childhood on White Island Lighthouse, part of Isles of Shoals, and Appledore Island. At 16 she married Levi Thaxter and had three sons, Karl, John, and Roland. The family spent winters on the mainland in Massachusetts, where Celia felt imprisoned by domestic duties in a city house. Her first poem, "Land-locked," was published in 1860 and was an immediate success. Soon she became widely published, with poems appearing in Harper's, Scribner's, and the Atlantic. With the means to spend more …

Finding Aid To The Collection Of Victoria Sackville-West Materials., Victoria Sackville-West, Colby College Special Collections

Finding Aids

The collection contains 27 letters and 4 greeting cards of personal correspondence written between 1947-1961, from V. Sackville-West at her home at Sissinghurst Castle in Kent, U.K., to Grace Mountcastle Martin in Stillwater, Oklahoma. Many of the letters convey the author's thanks for shipments of sugar and soap during times of rationing in the U.K.

V. [Victoria or "Vita"] Sackville-West, English poet, novelist, socialite and suffragette, was born in 1892 at her family's estate at Knole in Kent. Privately educated, she began writing poetry at age 11, and had produced 8 novels and 5 plays by the time of her …

Finding Aid To The Collection Of Louise Helen Coburn Materials, Louise Helen Coburn, Colby College Special Collections

Finding Aids

Louise Helen Coburn was born in Skowhegan, Maine on September 1, 1856, daughter of Stephen Coburn and Helen Sophia Miller. Coburn was Colby's second female graduate (after Mary Low Carver) in 1877, and graduated with Phi Beta Kappa honors. She also later received an honorary Litt. D. degree from Colby in 1914. Coburn's family was deeply tied to Colby College. Her father Stephen graduated in 1839, and the Coburn family was critical to Colby's early development as benefactors. Coburn was a co-founder, along with Mary Low Carver and others, of the Sigma Kappa Sorority. Coburn also later attended the Harvard …

Disc1 Knockout Rats Reveal Sexually Dimorphic Patterns Of Impairment Across Development, Stephanie S. Desrochers

Honors Theses

Schizophrenia is a chronic disorder characterized by three symptom categories: positive (hallucinations, delusions), negative (anhedonia, anxiety), and cognitive (sensory processing and memory deficits). We worked with a biallelic deletion of the Disrupted-in-schizophrenia-1 (DISC1) gene in Sprague-Dawley rats to facilitate our understanding of the biological bases of schizophrenia. Mutations of DISC1 are associated with a higher prevalence of schizophrenia. Adult DISC1 knockout, compared to wildtype, rats display features of schizophrenia-like outcomes in rodent models. The present study investigated the progression of the cognitive symptom deficits in prepulse inhibition (PPI), assessing animals at postnatal days 17 (pre-weaning), 26 (post-weaning), 39 (adolescent), and …