Life Sciences Commons^™

Biogeography Of Special Metabolites Produced By Ant-Associated Bacteria, Katherine Hansen

Scripps Senior Theses

There is an urgent and growing need for novel antibiotics with the growing prevalence of antibiotic-resistant pathogens. Ecologically-guided discovery is a strategy that focuses on how and where specially evolved metabolites such as antibiotics are used in nature. This strategy reveals unique active molecules with potential for human use. An unexplored niche with great potential for antibiotic discovery exists with Southwestern fungus-farming Trachymyrmex ants and their Actinobacteria symbionts. In exchange for nutrients from the ant, the ants’ bacterial symbiont produces antifungal molecules that protect the ants’ fungal cultivar from invasion by pathogenic microorganisms. They also produce antibacterial molecules to protect …

Variation In Soil-Mediated Drought Response Traits Between Sympatric Species Of Mimulus, Anna Reitman

Scripps Senior Theses

The ‘time limitation hypothesis’ is an evolutionary theory regarding evolution in angiosperms. The theory attributes ephemeral drought stress to transitions from a perennial to annual life history and an animal- to self-pollinating mating style. The most influential edaphic parameter on water availability is soil texture (i.e. grain size) due to its controls on porosity. Adhesion weakens with coarseness allowing for expedited rates of water loss via evaporation and percolation. The potential implications of coarse soil textures on major transitions in angiosperms due to drought mediation as the ‘time-limitation hypothesis’ proposes has yet to be thoroughly examined. Here, we grew two …

An Analysis Of Water Quality At Orange County, California Beaches, Naomi Meurice

Pomona Senior Theses

Beaches in Southern California are highly recreated by residents and visitors, making beaches socially and economically important. Public health departments in coastal communities are in charge of measuring water quality and ensuring it is safe for users. Research in the past has indicated that beach water quality gets worse after storms, with bacteria levels jumping on the day of a storm and staying high for up to five days. Studies have shown these spikes in bacteria to be associated with storm runoff, with beaches closer to runoff discharge locations experiencing more impact. However, prior research has not considered the period …

Examining Soil Microbial Diversity In Transition Zones Between Corn Fields And Restored Prairie In The Upper Midwest, Anna M. Burns

Scripps Senior Theses

Prairies were once the largest ecosystem in North America, but agriculture and settlement has destroyed up to 99% of their pre-colonization extent. Prairie restorations are a strategy to recover the biodiversity and carbon sequestration functions of these grasslands, but typically occur in isolated strips between agricultural fields. My thesis analyzes how effective prairie restorations in the Liberty Prairie (northeastern Illinois) are at recovering the diversity of the prairie soil microbiome, focusing on verrucomicrobia abundance, alpha diversity, and soil physical characteristics.

Effects Of Drought On Habitat Quality For Native Bees In Residential Gardens Of Claremont, Ca, Max Proctor

CMC Senior Theses

Over 1,500 of the 4000 bee species found in North America inhabit California. Native bees are declining however, largely due to climate change and agricultural intensification. Previous research shows that cities can sustain diverse bee communities, due to the diversity of ornamental flowers. Urban green space represents an opportunity for native bee conservation. Residential gardens provide lots of green space and are urban pollinator hotspots. Managing yards for increased floral resources and nesting habitat can benefit native bee communities. Turfgrass provides few floral or nesting resources and negatively correlates with bee diversity. The 2011-2017 California drought caused many homeowners to …

Footprints On The Prairie: Examining The Interlocking Land Histories Of The Liberty Prairie Reserve, Illinois, Anna M. Burns

Scripps Senior Theses

This thesis begins with the local history of the Liberty Prairie, the land where I conducted the ecological field-work that I later discuss in my second thesis on soil microbiome diversity (“Examining Soil Microbial Diversity in Transition Zones Between Corn Fields and Restored Prairie in the Upper Midwest"). I examine the Indigenous histories of the land, and the conflicts between the Bodwéwadmi and Euro-American settlers that resulted in the land being farmed for cattle, corn, and soy for over a hundred and fifty years. I then take a step back and analyze the broader historical contexts of Midwestern Corn Belt …

Understanding The Environmental Implications Of The Microbiome Of Canals In Bangkok, Thailand, Emma Tao

Scripps Senior Theses

The canals of Bangkok, Thailand hold significant economic and social value, yet the increasing urbanization of the city has resulted in increased water pollution. Agricultural runoff and urban waste contribute to the degradation of the water quality, which has impaired its safe usage by the people of the city. This study focused on analyzing the microbiome of the water in the canals in correlation with the surrounding environment, both in and out of the water. Ten sites along the Bangkok canals were analyzed. DNA was isolated for the sequencing of the 16s rRNA gene to determine the microbial diversity of …

Qualitative Analysis Of A Resource Management Model And Its Application To The Past And Future Of Endangered Whale Populations, Glenn Ledder

CODEE Journal

Observed whale dynamics show drastic historical population declines, some of which have not been reversed in spite of restrictions on harvesting. This phenomenon is not explained by traditional predator prey models, but we can do better by using models that incorporate more sophisticated assumptions about consumer-resource interaction. To that end, we derive the Holling type 3 consumption rate model and use it in a one-variable differential equation obtained by treating the predator population in a predator-prey model as a parameter rather than a dynamic variable. The resulting model produces dynamics in which low and high consumption levels lead to single …

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 …

Will There Be Changes In Sexually Differentiated Behaviors In Mice Manipulated For The Sry Gene As They Mature Into Adultood?, Subin Joo

CMC Senior Theses

Sexually differentiated behavior has been shown to be affected by both genes and hormones. The discovery of the SRY gene, which codes for the development of testes, lead to the development of the Four Core Genotypes model of mice, and the separation of sex chromosomes and its resulting gonadal hormones. Using the FCG model, this study aims to look at the development of sexually differentiated behavior in mice, and track how it changes throughout their life. FCG mice will be divided into individual and social housing, and repeated experiments carried out to test their reaction to both intact female and …

An Evaluation Of Antiparasitics Used To Treat The Sea Louse, Caligus Rogercresseyi, In Chilean Salmonid Farming, Dayla Woller

Scripps Senior Theses

Sea lice pose a global threat to open-net salmonid farming. As Chile is the second largest Atlantic salmon producer, they have a vested interest in mitigating infestations and increasing production. However, this will not be possible without 1) increased research on the underlying mechanisms behind sea lice infestations that will inform 2) governmental regulation of salmon farming. This increase in research and governmental regulation will only be possible through transparency on pesticide practices and sea louse monitoring data from companies operating in Chile. Taking these steps would bring Chile closer to being the largest producer of Atlantic salmon and an …

The Intersection Between Black Hair And The Environment: Hair As A Site For Environmental Justice And Sustainability, Dafina Matiku

Scripps Senior Theses

Currently, we are facing several global crises that include but are not limited to climate change, food insecurity, pollution of the body and environment, as well as racial, gender, and class inequities. This thesis seeks to understand how the natural hair movement, which strives to omit toxic chemicals while embracing textured hair, can be a tool of reconnecting to nature. As humans we are intrinsically part of ecosystems and nature, we must find our niche in it instead of occupying and destroying our environment entirely. The methodology includes compiling a small array of experiences that show the nuance of hair …

The Impact Of Tidal Elevation And Climate Change On The Growth And Performance Of Balanus Glandula, Sam Martin

Pitzer Senior Theses

Tidal elevation affects the survival, growth, and performance of intertidal organisms because it regulates their exposure to heat, waves, food availability, and a variety of other abiotic factors. While previous research has explored the relationship between temperature and the performance of the barnacle Balanus glandula, there are unanswered questions about how tidal elevation affects B. glandula performance and growth. I compared the growth of B. glandula at three tidal elevations in Friday Harbor, Washington, and estimated the metabolic cost of emersion at each tidal elevation using a cost equation gained from thermal performance curves and average daily maximum temperatures. …

Mapping Floral Resources For Bees Using Drone Imagery, Arya Massarat

HMC Senior Theses

Poor nutrition among modern day honey bee colonies is contributing to their decline. Yet understanding how the diversity and abundance of flowering species around a colony affects its health remains difficult because of the manual labor required to analyze these large foraging landscapes. We describe a procedure for automatically mapping the species of flowering plants around a colony from overlapping drone images. We developed a pipeline for stitching the images together, identifying plants within them, and classifying each plant by its species. The resulting map of the flowering species surrounding a colony could be used in future experiments that aim …

Antifungal Defense Molecules From Bacterial Symbionts Of North American Trachymyrmex Ants, Georgia Scherer

CMC Senior Theses

Defensive symbioses, in which microbes provide molecular defenses for an animal host, hold great potential as untapped sources of therapeutically useful antibiotics. Fungus-growing ants use antifungal defenses from bacterial symbionts to suppress pathogenic fungi in their nests. Preliminary chemical investigations of symbiotic bacteria from this large family of ants have uncovered novel antifungal molecules with therapeutic potential, such as dentigerumycin and selvamicin.

In this study, the bacterial symbionts of North American Trachymyrmex fungus-growing ants are investigated for antifungal molecules. Plate-based bioassays using ecologically-relevant fungal pathogens confirmed that these bacteria have antifungal activity. In order to purify and identify the antifungal …

The Chumash Heritage National Marine Sanctuary: An Exploration Of Changing The Discourse On Conservation, Arielle Ben-Hur

Pitzer Senior Theses

In 2015, the Northern Chumash Tribal Council submitted a National Marine Sanctuary Nomination to establish the Chumash Heritage National Marine Sanctuary– a means by which to ensure the protection of one of the most culturally and biologically diverse coastlines in the world. On October 5, 2015, John Armor of the National Oceanic and Atmospheric Administration (NOAA) responded to the nomination, adding it to the inventory of areas NOAA may consider in the future for national marine sanctuary designation.

In my thesis, I explore how the nomination of the Chumash Heritage National Marine Sanctuary acts as a platform from which Traditional …

The Finch Effect: Evolutionary Metaphors And Illiberal Democracy In Central And Eastern Europe, Abigail Woodfield

Claremont-UC Undergraduate Research Conference on the European Union

In recent years, several states in Central and Eastern Europe have seen democratic digression. Such illiberal resurgences came as a surprise to the many political scientists who assumed that the future of these states was democratic. Indeed, after the fall of the Soviet Union, the world largely regarded liberal democracy as the predominant system of government. The future seemed bright, and it was tempting to understand that future in evolutionary terms—just as humans evolved under natural selection to become the dominant species, democracy had survived a similar competition and defeated all other systems of government to become the dominant regime. …

Spot-On! Exploring Comprehension Of Ecological Concepts With Abstract Art Analogies, Jane Huggins

The STEAM Journal

Students enrolled in an online general studies course [GNM 2190: Extinct and Threatened Life] at Stockton University were presented with two different pieces of abstract art. They were asked to draw analogies from each piece of art to the ecological concepts studied in the course. Students provided written responses which were submitted as assignments in the learning management software, Blackboard [Bb]. This exercise was described as ‘open-ended’ by the instructor; no grading rubrics were used. Responses to each piece of art were collected from 47 students and were subsequently uploaded into Quirkosä software for qualitative analysis. Codes representing major concepts …

Shizen Nōhō: Restoring The Relationship Between Food, Nature, And People In Japan, Katharine Graham

Scripps Senior Theses

In Japan’s postwar era, agriculture has become highly industrialized, involving heavy machinery, chemical fertilizers, and pesticides, all in the name of “progress.” Through employing such practices, humans have attempted to improve upon nature’s way of doing things, and in turn have degraded the soil’s fertility, natural ecosystems, and human health. In response to this, Shizen Nōhō has emerged in Japan as an alternative way of cultivating food. Shizen Nōhō practitioners challenge the notion that we need chemical fertilizers, pesticides, and machinery to farm successfully. Rather, they advocate for a way of growing food that functions seamlessly with natural ecosystems. This …

Island Invasion: The Silent Crisis In Hawaii, Sophia Janssen

Pomona Senior Theses

Keeping out invasive species may, upon first review, seem like a trivial environmental cry from ecologists and deep environmentalists; a belated wish to return to an undeveloped world where nature was pristine. However invasive species create problems that impact all of us and can have far more severe consequences than changing a stunning landscape. These problems are heightened in islands like Hawaii, where the fragile ecosystems have developed over centuries of evolution and adaptation. The introduction of a disease-carrying mosquito can put the people of Hawaii at risk to many vector-born illnesses and create an epidemic, taking human life. The …

Role Of Managed Marine Areas On The Diversity And Individual Responses Of Rocky Intertidal Shore Grazers In Central Chile, Kathy Liu

Scripps Senior Theses

Many different types of marine benthic herbivores or “grazers” inhabit coastal intertidal zones and play a crucial role in inter- and shallow subtidal ecosystems. Chile has one of the most diverse intertidal zones, but many intertidal grazers are exploited for human consumption. Marine protected areas (MPAs) and marine management and exploitation areas (MEAs) are promising tools for Chile to combat over exploitation of these grazer and other marine resources. This study surveyed the impact of sites with contrasting management on the diversity and abundance of all intertidal grazers and their impact on the size frequency and shell length-body weight allometry …

Potential For Climate Induced Methane Hydrate Dissociation, Graham Macwilliams

Pomona Senior Theses

Methane hydrates are frozen deposits of methane and water found in high pressure or low temperature sediments. When these deposits destabilize, large quantities of methane can be emitted into the atmosphere. This is significant to climate change because methane has 25 times more greenhouse gas potential than Carbon Dioxide. Worldwide, it is estimated there are between 2500 and 10000 gigatons of methane stored in hydrate deposits. This represents more carbon than all fossil fuels on Earth. It is estimated that between 200 and 2000 gigatons of methane are stored in hydrates in Arctic waters acutely vulnerable to greenhouse warming. Over …

Restoration Of Mauri (Life-Force) To Okahu Bay: Investigation Of The Cultural, Social, And Environmental Restoration, Emily Freilich

Pomona Senior Theses

This thesis investigated the restoration of mauri (life-force) to Ōkahu Bay, Auckland New Zealand. Ōkahu Bay is part of the land and waters of Ngāti Whātua Ōrākei, a Māori hapū (sub-tribe). Ngāti Whātua Ōrākei has been driving the restoration, restoring Ōkahu Bay based on their worldview, visions, and concerns. This vision and control of the restoration process allows them to bring in the hapū in sustainable engagement and have the long-term vision and commitment necessary for self-determination. However, while there has been progress with projects and improved decision-making authority, hapū members are still not seeing their whānau (family) swimming in …

Restoration Of Mauri (Life-Force) To Ōkahu Bay: Investigation Of A Community Driven Restoration Process, Emily Freilich

Pomona Senior Theses

This thesis investigated the restoration of mauri (life-force) to Ōkahu Bay, Auckland New Zealand. Ōkahu Bay is part of the land and waters of Ngāti Whātua Ōrākei, a Māori hapū (sub-tribe). Ngāti Whātua Ōrākei has been driving the restoration, restoring Ōkahu Bay based on their worldview, visions, and concerns. This vision and control of the restoration process allows them to bring in the hapū in sustainable engagement and have the long-term vision and commitment necessary for self-determination. However, while there has been progress with projects and improved decision-making authority, hapū members are still not seeing their whānau (family) swimming in …

Science And Sentiment: Affecting Change In Environmental Awareness, Attitudes, And Actions Through The Daily Nature Project, Elizabeth D. Haynes Poronsky

The STEAM Journal

Knowledge about what motivates pro-environmental behavior is important to organizations that seek to encourage environmental stewardship. Research suggests that targeting emotions and beliefs about nature can be more effective in changing environmental actions than increasing knowledge. Daily Nature, a site on the social media platform Facebook, features a daily nature photograph, a quote from a notable historical person and a related lyrical written passage. The popularity of this site lends credence to the appeal of interdisciplinary formats, and underscores the benefits of encouraging emotional and aesthetic ties to nature.

Slowing The Evolution And Outbreak Of Antibiotic Resistance, Connie Okasaki

HMC Senior Theses

Antibiotic resistance is a problem of significant and growing international concern, in part due to the rapid evolution of new resistances. One potentially important factor in the emergence of resistance is concentrated antibiotic use in environments such as hospitals. Such high use creates a strong selective pressure for pathogens to evolve resistance. We analyze some strategies hospitals can use to slow the evolution of resistance, and estimate the length of the delay between evolution and outbreak of resistance.

Matrix Model Analysis Of A Coastal Northern California Subpopulation Of The Western Snowy Plover (Charadrius Alexandrinus Nivosus), Jaclyn Grace Stewart

CMC Senior Theses

Shorebirds are increasingly threatened by introduced predators, invasive grasses, and human disturbance. Matrix models can be used to predict population growth and assess management options. The Pacific coast population of the western snowy plover, Charadrius alexandrinus nivosus, is listed as threatened under the Endangered Species Act, largely due to high rates of nest predation. A matrix model for the entire Pacific coast metapopulation of western snowy plovers was published in 1999 by Nur et al., but population growth has not been comprehensively reassessed since, even after development of a recovery plan (USFWS 2007) and extensive management intervention. I built …

Ecoscience + Art Initiative: Designing A New Paradigm For College Education, Scholarship, And Service, Changwoo Ahn

The STEAM Journal

The paper presents a new initiative, EcoScience + Art, which blooms at George Mason University. The creator explains the background, history, and recent activities of the initiative, and also introduces an on-going special project called “The Rain Project”, a student participatory project to design, construct, and monitor a green infrastructure (i.e., floating wetland) for sustainable stormwater management on campus. The special project is geared to design and present a new paradigm to integrate college education, scholarship, and service. The relevance of the initiative and the special project to STEAM education is discussed.

A Fistful Of Polemoniaceae: New Names And Combinations, J. Mark Porter, Robert W. Patterson

Aliso: A Journal of Systematic and Floristic Botany

New taxa, names, and combinations are provided for five genera in Polemoniaceae: Dayia, Giliastrum, Leptosiphon, Linanthus, and Loeselia. Combinations include the transfer to Dayia of two species formerly included in Ipomopsis and one in Bryantiella (Dayia glutinosa, D. havardii, and D. sonorae), as well as the return of Giliastrum stewartii to species rank. A new name is offered for Linanthus aureus when transferred into Leptosiphon: Leptosiphon chrysanthus and its subspecies, L. chrysanthus subsp. decorus. New combinations for infraspecific taxa are made available for Linanthus californicus (subspp. glandulosus and tomentosus …

Robert Folger Thorne—A Botanical Legacy

Aliso: A Journal of Systematic and Floristic Botany

Robert F. Thorne, distinguished botanist and former curator of the herbarium at Rancho Santa Ana Botanic Garden, left a rich botanical legacy. Contributions featured include a list of his articles appearing in Aliso: A Journal of Systematic and Evolutionary Botany, as well a list of plant taxa named for him.