Digital Commons Network^™

Heading For A Breakdown: Assessing Evolution Through The Hybridization Of Two Sexual Systems, Diamanda A. Zizis

Honors Theses

Hybridization is an important evolutionary pathway that has contributed to the world’s vast biodiversity. In plants, especially angiosperms, hybridization is known to be an important mechanism for speciation, phenotypic divergence, and changes in reproductive systems. Solanum species present an ideal system to investigate how hybridization between two different sexual systems impacts the reproductive and phenotypic biology of the hybrid progeny. Hybrid seeds were acquired from crosses between Australian Solanum species Solanum dioicum (dioecious) and S. ultraspinosum (andromonoecious) in order to track what happens when you cross two plants with different sexual systems. Vegetative and floral morphological measurements were conducted, and …

Cleaning The Variable Mess: A Population Genomics Approach To Understanding The Evolutionary History Of A Complicated Plant Group, Claire Marino

Honors Theses

The Solanum dioicum clade is a group of Australian bush tomatoes consisting primarily of species native to Western Australia and the Northern Territory whose species delimitations tend to be quite unclear. Since David Symon’s monograph A Revision of the Genus Solanum in Australia was published in 1981, little additional progress has been made in clarifying these relationships. In this project, a population genomics approach was used to analyze the relationships and delimitations between three species within the S. dioicum clade: Solanum dioicum, S. carduiforme, and S. ossicruentum. The use of population genomics methods is advantageous to understanding …

Conditioned Territory Defense In Madagascar Hissing Cockroaches (Gromphadorhina Portentosa), Macy R. Albaitis

Honors Theses

In male blue gourami fish (Trichogaster trichopterus), signaled presentation of a male rival produces an aggressive conditioned response that results in an increased likelihood of the male winning the contest (Hollis, 1984). I replicated this classic study in a species that also shows territorial aggression: the Madagascar hissing cockroach (MHC; Gromphadorhina portentosa). During training, four adult male MHCs were designated as “CS+” animals and received a light (NS) followed by visual access to a rival male (US). Simultaneously, another group of four adult male MHCs designated as “UNC” animals received the light (NS) and visual access to a …

Genetic Diversity & Connectivity Of Chasmanthium Latifolium (Poaceae) In Pennsylvania & The Effect On Conservation Status Of A Rare Species, Jonathan D. Hayes

Honors Theses

Chasmanthium latifolium (Michx.) Yates (Poaceae) is a loosely colonial, rhizomatous, perennial grass species that lives in riparian habitats, making it fittingly referred to as river oats. Native to the southern Midwest and the eastern half of the United States, C. latifolium reaches the northeastern edge of its range in Pennsylvania. Within Pennsylvania, eleven extant C. latifolium populations are found along four waterways: the Monongahela River, the Susquehanna River, and two tributaries to the Susquehanna River. This limited state distribution exhibits an east-west disjunct distribution, where western populations are largely separated from eastern populations with one centrally located population. Between the …

A Foray Into The Interval Timing Capabilities Of Tufted Capuchin Monkeys (Cebus [Sapajus] Apella), Gryff Griffin

Honors Theses

Time is a critical part of life and timing on the range from milliseconds to minutes has proven to be critical for several behaviors such as foraging and movement. While the exact neurological structures of interval timing are currently undefined, several studies have been completed comparing the interval timing capabilities of humans and nonhuman primates. However, these studies have unanimously utilized members of Macaca, which limits the abilities for researchers to make apt comparisons between humans and all nonhuman primates. This study sought to investigate whether tufted capuchins (Cebus [Sapajus] apella) have the capability to measure time …

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 …

Examining The Effects Of Fadrozole, An Aromatase Inhibitor, On Testosterone And Estrogen Production Of Domestic Chicken Embryos (Gallus Gallus), Abby E. Joseph

Honors Theses

The hypothalamic-pituitary-gonadal (HPG) axis is responsible for the production of the hormones testosterone and estradiol, and testosterone is thought to contribute to regulation of the axis through a negative feedback mechanism. Regulation by negative feedback involves the product of a pathway turning off that pathway when enough product is made. However, because the enzyme P450 aromatase converts testosterone to estradiol, estradiol may also contribute to regulation of the HPG axis and other phenomena that have been attributed to testosterone, like the inhibition of immune function. Previous studies have injected birds with an aromatase inhibitor (presumably reducing estradiol production) and shown …

Role Of Nest Site Microclimate And Food Availability In Chick Development And Reproductive Success In Black-Legged Kittiwakes (Rissa Tridactyla), Lindsay Mae Lacey

Honors Theses

Seabirds are marine top predators, and as such are often studied as bioindicators of climate shifts (Oswald and Arnold 2012). Though many studies have analyzed the effect of macroclimatic variation on marine prey species availability and thus seabirds, few have analyzed effects of microclimate - fine spatial patterns of climate (Mantua and Hare 2002; Hatch 2013; Kim and Monaghan 2005a). I tested the hypothesis that localized temperature and humidity at nest sites interact with food availability to alter black-legged kittiwake (Rissa tridactyla) nest site quality, chick body condition during growth and development, and reproductive parameters including Julian lay …

Investigating The Relationship Between Sulcogyral Patterns And Structural And Functional Connectivity Metrics In The Orbitofrontal Cortex, Bethany M. Blass

Honors Theses

Located within the frontal lobe, the human orbitofrontal cortex (OFC) is widely known for its roles in sensory integration, emotion processing, decision-making, and goal-directed behaviors. Atypical structural organization of the OFC may explain atypical social or motivational behaviors displayed by individuals with brain disorders, such as bipolar disorder patients (BP).

The human brain can be imaged using magnetic resonance imaging (MRI) to reveal interesting aspects of the underlying brain architecture. This brain is composed of different tissue types, including gray and white matter, as well as various morphological features, including sulci & gyri. Within the OFC, the sulci can be …

The Effects Of Prenatal Exposure To Altered Melatonin Levels On Hippocampal Gene Expression In The Male Rat, Anna Uehara

Honors Theses

The stability of the circadian rhythm for mammals depends on the levels of serotonin and melatonin, neurohormones that signal for lightness and darkness, respectively. Disruption in the stability of neurohormones has been shown to be a critical factor in psychopathological disorders in humans. For example, altering levels of melatonin in utero through administration of melatonin or the melatonin receptor antagonist, luzindole, has been shown to cause changes in developmental growth and adult behavior in the male rat. Analysis of relative adult hippocampal gene expression with RT-PCR revealed differences in ARNTL expression that suggested abnormality in clock gene expression of the …

Alteration In 5ht1a Receptor Activity From A Prenatal Exposure To Dexamethasone In A Stressed And Non-Stressed Adult Male Rat, Darshan S. Shah

Honors Theses

Synthetic glucocorticoids (GC) are used as a clinical therapeutic to stimulate lung development in fetuses that present the risk of preterm delivery. Previous studies have shown that a prenatal exposure to Dexamethasone (DEX) causes a disturbance in normal GC mediation of neuritic outgrowth, cell signaling, and serotonergic systems. Our hypothesis is that a prenatal exposure to DEX during the third trimester of pregnancy alters 5HT1A receptor function. Pregnant dams were injected daily with 150μg/ml/kg of DEX from gestation day 14 through 19. Control dams were treated with and equal volume of saline. Swim stress followed by elevated plus maze testing …