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- Title
- Ocean Acidification Effects on Photosynthesis in Tropical Marine Macroalgae.
- Creator
- Zweng, Regina C., Koch, Marguerite, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Field data from CO2 vents, a current model of future ocean acidification conditions, show a positive correlation between elevated seawater pCO2 and fleshy macroalgal abundance, as well as a negative correlation between elevated seawater pCO2 and calcareous macroalgal abundance on coral reefs. One underlying physiological mechanism for increases of fleshy macroalgae species in response to greater pCO2 could be an increase in their photosynthesis. Furthermore, inorganic carbon use mechanisms,...
Show moreField data from CO2 vents, a current model of future ocean acidification conditions, show a positive correlation between elevated seawater pCO2 and fleshy macroalgal abundance, as well as a negative correlation between elevated seawater pCO2 and calcareous macroalgal abundance on coral reefs. One underlying physiological mechanism for increases of fleshy macroalgae species in response to greater pCO2 could be an increase in their photosynthesis. Furthermore, inorganic carbon use mechanisms, irradiance and depth may influence species-specific responses to ocean acidification. Therefore, this thesis aimed to discern carbon use strategies and photosynthetic responses to elevated pCO2 of dominant tropical fleshy and calcareous macroalgae. All species studied were able to utilize HCO3 - for photosynthesis. 33% of calcifying macroalgae and 80% of fleshy macroalgae had increased photosynthetic rates in response to lower pH. Thus, future conditions of OA may perpetuate or exacerbate the abundance of fleshy seaweeds at the expense of calcareous species.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00004879, http://purl.flvc.org/fau/fd/FA00004879
- Subject Headings
- Marine algae--Ecophysiology., Algal communities--Monitoriing., Coral reef ecology.
- Format
- Document (PDF)
- Title
- INTRASEXUAL SELECTION AND THE ELABORATION OF A MATING SIGNAL IN THE BACHMAN’S SPARROW (PEUCEA AESTIVALIS).
- Creator
- Ziadi, Paula, Anderson, Rindy, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Vocal communication is central to the coordination of social behavior in many vertebrate species, and it has been particularly well studied in songbirds, which use their songs in different contexts to convey information about the singer or its environment (Catchpole and Slater 2008; Alger et al. 2016). While it is widely accepted that the songs of oscine passerine birds (the songbirds) have two main social functions: intrasexual competition, and courtship (Catchpole and Slater 2008), the...
Show moreVocal communication is central to the coordination of social behavior in many vertebrate species, and it has been particularly well studied in songbirds, which use their songs in different contexts to convey information about the singer or its environment (Catchpole and Slater 2008; Alger et al. 2016). While it is widely accepted that the songs of oscine passerine birds (the songbirds) have two main social functions: intrasexual competition, and courtship (Catchpole and Slater 2008), the evolution of large and complex song repertoires remains an evolutionary puzzle (Byers and Kroodsma 2009). The question is: why do some songbird species produce an elaborate vocal repertoire, while other species carry out courtship and competition with a far smaller and simpler repertoire? In this thesis I examine the adaptive value (social function) of song in malemale competition with an eye toward understanding how intrasexual selection may have driven the elaboration of the male Bachman’s sparrow (Peucea aestivalis) vocal repertoire.
Show less - Date Issued
- 2019
- PURL
- http://purl.flvc.org/fau/fd/FA00013352
- Subject Headings
- Bachman's sparrow, Songbirds--Behavior, Songbirds--Vocalization, Birds--Sexual behavior
- Format
- Document (PDF)
- Title
- A DISINHIBITORY MICROCIRCUIT FOR GATED CEREBELLAR LEARNING.
- Creator
- Zhang, Ke, Christie, Jason, Dawson-Scully, Ken, Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
- Abstract/Description
-
Performance motor errors trigger animals’ adaptive learning behaviors to improve the accuracy and efficiency of the movement. The cerebellum is one of the key brain centers for encoding motor performance and motor learning. Climbing fibers relay information related to motor errors to the cerebellar cortex, evoking elevation of intracellular Ca2+ signals at Purkinje cell dendrites and inducing plasticity at coactive parallel fiber synapses, ultimately recalibrating sensorimotor associations to...
Show morePerformance motor errors trigger animals’ adaptive learning behaviors to improve the accuracy and efficiency of the movement. The cerebellum is one of the key brain centers for encoding motor performance and motor learning. Climbing fibers relay information related to motor errors to the cerebellar cortex, evoking elevation of intracellular Ca2+ signals at Purkinje cell dendrites and inducing plasticity at coactive parallel fiber synapses, ultimately recalibrating sensorimotor associations to alter behavior. Molecular layer interneurons (MLIs) inhibit Purkinje cells to modulate dendritic excitability and action potential output. How MLIs contribute to the regulation and encoding of climbing fiber-evoked adaptive movements remains poorly understood. In this dissertation, I used genetic tools to manipulate the activity of MLIs while monitoring Purkinje cell dendritic activity during a cerebellum-dependent motor learning task with different contexts to evaluate how MLIs are involved in this process. The results show that by suppressing dendritic Ca2+ signals in Purkinje cells, MLI activity coincident with climbing fiber-mediated excitation prevents the occurrence of learning when adaptation is not necessary. On the other hand, with error signals present, disinhibition onto Purkinje cells, mediated by MLI-MLI microcircuit, unlocked the ability of climbing fibers to induce plasticity and motor learning.
Show less - Date Issued
- 2020
- PURL
- http://purl.flvc.org/fau/fd/FA00013526
- Subject Headings
- Cerebellum, Interneurons, Purkinje cells, Dendrites, Sensorimotor integration, Neuroplasticity
- Format
- Document (PDF)
- Title
- Genetic and Neural Mechanisms Regulating the Interaction Between Sleep and Metabolism in Drosophila Melanogaster.
- Creator
- Yurgel, Maria E., Keene, Alex C., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Dysregulation of sleep and metabolism has enormous health consequences. Sleep loss is linked to increased appetite and insulin insensitivity, and epidemiological studies link chronic sleep deprivation to obesity-related disorders. Interactions between sleep and metabolism involve the integration of signalling from brain regions regulating sleep, feeding, and metabolism, as well as communication between the brain and peripheral organs. In this series of studies, using the fruit fly as a model...
Show moreDysregulation of sleep and metabolism has enormous health consequences. Sleep loss is linked to increased appetite and insulin insensitivity, and epidemiological studies link chronic sleep deprivation to obesity-related disorders. Interactions between sleep and metabolism involve the integration of signalling from brain regions regulating sleep, feeding, and metabolism, as well as communication between the brain and peripheral organs. In this series of studies, using the fruit fly as a model organism, we investigated how feeding information is processed to regulate sleep, and how peripheral tissues regulate sleep through the modulation of energy stores. In order to address these questions, we performed a large RNAi screen to identify novel genetic regulators of sleep and metabolism. We found that, the mRNA/DNA binding protein, Translin (trsn), is necessary for the acute modulation of sleep in accordance with feeding state. Flies mutant for trsn or selective knockdown of trsn in Leucokinin (Lk) neurons abolishes starvation-induced sleep suppression. In addition, genetic silencing of Lk neurons or a mutation in the Lk locus also disrupts the integration between sleep and metabolism, suggesting that Lk neurons are active during starvation. We confirmed this hypothesis by measuring baseline activity during fed and starved states. We found that LHLK neurons, which have axonal projections to sleep and metabolic centers of the brain, are more active during starvation. These findings suggest that LHLK neurons are modulated in accordance with feeding state to regulate sleep. Finally, to address how peripheral tissues regulate sleep, we performed an RNAi screen, selectively knocking down genes in the fat body. We found that knockdown of Phosphoribosylformylglycinamidine synthase (Ade2), a highly conserved gene involved the biosynthesis of purines, regulates sleep and energy stores. Flies heterozygous for two Ade2 mutations are short sleepers and this effect is partially rescued by restoring Ade2 to the fly fat body. These findings suggest Ade2 functions within the fat body to promote both sleep and energy storage, providing a functional link between these processes. Together, the experimental evidence presented here provides an initial model for how the peripheral tissues communicate to the brain to modulate sleep in accordance with metabolic state.
Show less - Date Issued
- 2018
- PURL
- http://purl.flvc.org/fau/fd/FA00013163
- Subject Headings
- Drosophila melanogaster, Sleep, Metabolism
- Format
- Document (PDF)
- Title
- Visual wavelength discrimination by the loggerhead turtle, Caretta caretta.
- Creator
- Young, Morgan, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Little is known about the visual capabilities of marine turtles. The ability to discriminate between colors has not been adequately demonstrated on the basis of behavioral criteria. I used a three-part methodology to determine if color discrimination occurred. FIrst, I exposed naèive, light-adapted hatchlings to either a blue, green or yellow light. I manipulated light intensity to obtain a behavioral phototaxis threshold to each color, which provided a range of intensities we knew turtles...
Show moreLittle is known about the visual capabilities of marine turtles. The ability to discriminate between colors has not been adequately demonstrated on the basis of behavioral criteria. I used a three-part methodology to determine if color discrimination occurred. FIrst, I exposed naèive, light-adapted hatchlings to either a blue, green or yellow light. I manipulated light intensity to obtain a behavioral phototaxis threshold to each color, which provided a range of intensities we knew turtles could detect. Second, I used food to train older turtles to swim toward one light color, and then to discriminate between the rewarded light and another light color ; lights were presented at intensities equally above the phototaxis threshold. Lastly, I varied light intensity so that brightness could not be used as a discrimination cue. Six turtles completed this task and showed a clear ability to select a rewarded over a non-rewarded color, regardless of stimulus intensity. Turtles most rapidly learned to associate shorter wavelengths (blue) with food. My results clearly show loggerheads have color vision. Further investigation is required to determine how marine turtles exploit this capability.
Show less - Date Issued
- 2012
- PURL
- http://purl.flvc.org/FAU/3352879
- Subject Headings
- Color vision, Visual discrimination, VIsual perception, Selectivity (Psychology), Photoreceptors, Loggerhead turtle, Orientation, Sea turtles, Orientation, Animal navigation
- Format
- Document (PDF)
- Title
- Effects of parasitism on the reproduction of common snook.
- Creator
- Young, Joy M., Hughes, Colin, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
The effect of parasitism on the individual, and on a population, is one of the least understood and poorly studied areas of fish ecology. Parasites compete for maternal energetic reserves required for the production of viable eggs and offspring; thus parasites can directly influence population dynamics by lowering the number of offspring that survive to produce. The goal of this work was to explore the effect of parasitism on the reproductive potential of fish. Traditional measures of somatic...
Show moreThe effect of parasitism on the individual, and on a population, is one of the least understood and poorly studied areas of fish ecology. Parasites compete for maternal energetic reserves required for the production of viable eggs and offspring; thus parasites can directly influence population dynamics by lowering the number of offspring that survive to produce. The goal of this work was to explore the effect of parasitism on the reproductive potential of fish. Traditional measures of somatic energy reserves and body condition were examined along with newer measures of fatty acids present in eggs to approximate reproductive potential. Eighty female common snook, Centropomus undecimalis, were collected during spawning season (mid April to mid October) from four spawning aggregations along the southeastern coast of Florida and examined for a suite of biological, reproductive, and parasite infection measures. General linear models were used to model somatic indices, body condition, fatty acid composition and the ratios of fatty acids in eggs as a function of parasite infection parameters, host age, capture location, capture month and year. All fish were included in the somatic indices and body condition analysis while a subset of 40 fish were used in the analysis on fatty acid composition and the ratios of fatty acids in eggs.
Show less - Date Issued
- 2015
- PURL
- http://purl.flvc.org/fau/fd/FA00004424, http://purl.flvc.org/fau/fd/FA00004424
- Subject Headings
- Aquaculture -- Environmental aspects, Centropomus undecimalis -- Physiology, Fish culture -- Health aspects, Fishes -- Ecophysiology, Parasitism, Snook -- Development, Snook -- Physiology
- Format
- Document (PDF)
- Title
- Inhibition of the Growth and Spread of Human Prostate Cancer.
- Creator
- Yi, Zoey, Hartmann, James, Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
- Abstract/Description
-
Prostate cancer, the most frequent non-skin cancer, is the second leading cause of cancer-related deaths in males within the United States. Men diagnosed with metastatic prostate cancer have a 5-year survival rate of approximately 30%. Goals of this study were to produce a combination of compounds that are effective against the disease with minimal side effects on normal cells, especially those of the immune system. This study showed KBU2046 in combination with calcitriol, limit proliferation...
Show moreProstate cancer, the most frequent non-skin cancer, is the second leading cause of cancer-related deaths in males within the United States. Men diagnosed with metastatic prostate cancer have a 5-year survival rate of approximately 30%. Goals of this study were to produce a combination of compounds that are effective against the disease with minimal side effects on normal cells, especially those of the immune system. This study showed KBU2046 in combination with calcitriol, limit proliferation, inhibit migration, and are cytotoxic in a testosterone dependent human prostate cancer cell line. Organic compounds, ellagic acid and curcumin were tested alone and in combination with either calcitriol or KBU2046. No combinations were as effective as KBU2046 and calcitriol in inhibiting migration and proliferation of LNCaP cells. The findings of this study support further investigation into therapeutic use of a combination of KBU2046 and calcitriol in prevention and remission of human prostate cancer.
Show less - Date Issued
- 2023
- PURL
- http://purl.flvc.org/fau/fd/FA00014242
- Subject Headings
- Prostate--Cancer, Prostate--Cancer--Treatment--Research, Prostate--Cancer--Prevention, Calcitriol
- Format
- Document (PDF)
- Title
- Thermodynamics-structure correlations of interactions between metalloproteinases and tissue inhibitors of metalloproteinase variants.
- Creator
- Wu, Ying., Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
The 23 matrix metalloproteinases (MMPs) in humans catalyze the turnover of all protein components of the extracellular matrix (ECM) and have important roles in tissue remodeling, wound healing, embryo implantation, cell migration and shedding of cell surface proteins. Excess MMP activities are associated with many diseases including arthritis, heart disease and cancer. The activities of MMPs are regulated by a family of four protein inhibitors, the tissue inhibitors of metalloproteinases ...
Show moreThe 23 matrix metalloproteinases (MMPs) in humans catalyze the turnover of all protein components of the extracellular matrix (ECM) and have important roles in tissue remodeling, wound healing, embryo implantation, cell migration and shedding of cell surface proteins. Excess MMP activities are associated with many diseases including arthritis, heart disease and cancer. The activities of MMPs are regulated by a family of four protein inhibitors, the tissue inhibitors of metalloproteinases (TIMPs), that are endogenous inhibitors of matrix metalloproteinases (MMPs), ADAMs (A Disintegrin And Metalloproteinase) and ADAMTS (disintegrin-metalloproteinase with thrombospmdin motifs) .... The balance between TIMPs and active metzinicins is very important and imbalances are linked to human diseases such as arthritis, cancer, and atherosclerosis. The engineering of TIMPs to produce specific inhibitors of individual MPs could provide new therapeutic principles for disease treatment, but this requires a detailed understanding of the biophysical and structural basis of the interactions of TIMPs and MMPs and ADAMs.
Show less - Date Issued
- 2012
- PURL
- http://purl.flvc.org/FAU/3356904
- Subject Headings
- Proteolytic enzymes, Metalloproteinase, Inhibitors, Apoptosis, Extracellular matrix proteins
- Format
- Document (PDF)
- Title
- A role for polynucleotide phosphorylase in protecting cells and controlling RNA quality under oxidative stress.
- Creator
- Wu, Jinhua., Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
RNA damage occurring under oxidative stress has been shown to cause RNA dysfunction and must be detrimental to cells and organisms. We propose that damaged RNA can be removed by specific RNA surveillance activities. In this work, we investigated the role of polynucleotide phosphorylase (PNPase), a 3'->5' exoribonuclease, in protecting the cells against oxidative stress and eliminating oxidatively-damaged RNA. Previously, it was reported that E. coli PNPase has a higher affinity to poly(8-oxoG...
Show moreRNA damage occurring under oxidative stress has been shown to cause RNA dysfunction and must be detrimental to cells and organisms. We propose that damaged RNA can be removed by specific RNA surveillance activities. In this work, we investigated the role of polynucleotide phosphorylase (PNPase), a 3'->5' exoribonuclease, in protecting the cells against oxidative stress and eliminating oxidatively-damaged RNA. Previously, it was reported that E. coli PNPase has a higher affinity to poly(8-oxoG:A). We further confirmed that E. coli PNPase can specifically bind to an oxidized RNA with a high affinity. An E. coli strain deficient in PNPase (pnp) is hypersensitive to hydrogen peroxide (H2O2). Importantly, the level of H2O2-induced RNA damage, measured by the content of 8-hydroxyguanosine, increases significantly in the pnp mutant cells. Consistent with the notion that PNPase plays a direct role in these processes, introduction of the pnp gene encoding E. coli PNPase can restore the viability and RNA oxidation level of the pnp mutant cells in response to H2O2 treatment. Interestingly, degradosome-association is not required for PNPase to protect cell against oxidative stress. PNPase is evolutionary conserved in most of organisms of all domains of life. The human polynucleotide phosphorylase (hPNPase) localizes mainly in mitochondria and plays pleiotropic roles in cell differentiation and has been previously shown to bind 8- oxoG-RNA with a high affinity. Here we show that similar to E. coli PNPase, hPNPase plays an indispensable role in protecting HeLa cells against oxidative stress. The viability in HeLa cell and 8-oxoG levels in RNA are inversely correlated in response to H2O2- treatment. After removal of oxidative challenge, the elevated level of 8-oxoG in RNA decreases, suggesting the existence of surveillance mechanism(s) for cleaning up oxidized RNA., We have shown that hPNPase may be responsible for the surveillance of oxidized RNA in mammalian cells.Overexpresion of hPNPase reduces RNA oxidation and increases HeLa cell viability against H2O2 insult. Conversely, hPNPase knockdown decreases the viability and increases 8-oxoG level in HeLa cells exposed to H2O2. Taken together, our results suggest that RNA oxidation is a challenging problem for living organisms, and PNPase may play an important role in protecting both prokaryotic and eukaryotic cells by limiting damage to RNA under oxidative stress.
Show less - Date Issued
- 2008
- PURL
- http://purl.flvc.org/FAU/186302
- Subject Headings
- RNA, Metabolism, Biopolymers, Physiological transport, Bacterial genetics, Proteins, Synthesis, Cellular signal transduction
- Format
- Document (PDF)
- Title
- Origins, movements, and foraging behavior of Hawksbill Sea Turtles (Eretmochelys imbricata) in Palm Beach County waters, Florida, USA.
- Creator
- Wood, Lawrence D., Milton, Sarah L., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
This dissertation examined the natal origins, home-range, and in-situ foraging behavior of an aggregation of sub-adult hawksbill turtles (Eretmochelys imbricata) found off the coast of Palm Beach County, Florida. Surveys were conducted on approximately 30 linear km of reef between 15 and 30 m in depth. Tissue samples were retrieved from 112 turtles for mtDNA haplotype determination. GPS-linked satellite transmitters were deployed on six resident sub-adults, resulting in both minimum convex...
Show moreThis dissertation examined the natal origins, home-range, and in-situ foraging behavior of an aggregation of sub-adult hawksbill turtles (Eretmochelys imbricata) found off the coast of Palm Beach County, Florida. Surveys were conducted on approximately 30 linear km of reef between 15 and 30 m in depth. Tissue samples were retrieved from 112 turtles for mtDNA haplotype determination. GPS-linked satellite transmitters were deployed on six resident sub-adults, resulting in both minimum convex polygon (MCP) and 95%, 50%, and 25% kernel density estimates (KDE) of home-range size. A foraging ethogram was developed, and sequential analysis performed on thirty videos (141 total minutes) of in-situ foraging behavior. Seventeen total haplotypes were identified in this aggregation, the majority (75%) of which represented rookeries on Mexico’s Yucatan Peninsula. Other sources, from most to least important, include Barbados, Costa Rica, Puerto Rico, Antigua, and the U.S. Virgin Islands.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004339
- Subject Headings
- Animal behavior, Animal orientation, Hawksbill turtle -- Ecology, Predation (Biology), Sea turtles -- Habitat, Wildlife conservation, Wildlife management
- Format
- Document (PDF)
- Title
- Analysis of morphology, growth rate, and fragmentation of the endangered lichen species Cladonia Perforata.
- Creator
- Witmer, David Warren, Moore, Jon, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Cladonia perforata is an endangered lichen endemic to the Atlantic Coastal Ridge, Lake Wales Ridge, Southwest Florida, and the North Gulf Coast of Florida. In all but a single locality, C. perforata relies entirely on asexual reproduction through fragmentation for reproduction, dispersal, and recruitment. This study suggests a positive correlation between fragment size and survivability of fragments after one year. The average thallus grew at a rate of 10.42% per year and younger branches of...
Show moreCladonia perforata is an endangered lichen endemic to the Atlantic Coastal Ridge, Lake Wales Ridge, Southwest Florida, and the North Gulf Coast of Florida. In all but a single locality, C. perforata relies entirely on asexual reproduction through fragmentation for reproduction, dispersal, and recruitment. This study suggests a positive correlation between fragment size and survivability of fragments after one year. The average thallus grew at a rate of 10.42% per year and younger branches of a thallus grew at a quicker rate than older branches. Additionally, a review of thalli morphology suggests C. perforata has a diverse form, and becomes more bifurcated as it increases in size.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004172, http://purl.flvc.org/fau/fd/FA00004172
- Subject Headings
- Cladonia, Fragmented landscapes, Lichens -- North America, Symbiosis
- Format
- Document (PDF)
- Title
- Alternative Biological Roles of Methionine Sulfoxide Reductases in Drosophila melanogaster.
- Creator
- Wilson, Kelsey, Binninger, David, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
The oxidation of methionine (Met) into methionine sulfoxide (met-(o)) leads to deleterious modifications to a variety of cellular constituents. These deleterious alterations can be reversed by enzymes known as methionine sulfoxide reductases (Msr). The Msr (MsrA and MsrB) family of enzymes have been studied extensively for their biological roles in reducing oxidized Met residues back into functional Met. A wide range of studies have focused on Msr both in vivo and in vitro using a variety of...
Show moreThe oxidation of methionine (Met) into methionine sulfoxide (met-(o)) leads to deleterious modifications to a variety of cellular constituents. These deleterious alterations can be reversed by enzymes known as methionine sulfoxide reductases (Msr). The Msr (MsrA and MsrB) family of enzymes have been studied extensively for their biological roles in reducing oxidized Met residues back into functional Met. A wide range of studies have focused on Msr both in vivo and in vitro using a variety of model organisms. More specifically, studies have noted numerous processes affected by the overexpression, under expression, and silencing of MsrA and MsrB. Collectively, the results of these studies have shown that Msr is involved in lifespan and the management of oxidative stress. More recent evidence is emerging that supports existing biological functions of Msr and theorizes the involvement of Msr in numerous biological pathways.
Show less - Date Issued
- 2018
- PURL
- http://purl.flvc.org/fau/fd/FA00005980
- Subject Headings
- Drosophila melanogaster, Methionine Sulfoxide Reductases, Oxidative stress
- Format
- Document (PDF)
- Title
- Cellular Computation in Primary Visual Cortex.
- Creator
- Wilson, Daniel E., Fitzpatrick, David, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Individual neurons in the primary visual cortex respond selectively to different features of visual stimuli, such as spatial orientation or direction of motion. A longstanding goal in systems neuroscience has been to understand the transformations single cells perform as they integrate synaptic inputs to generate spiking output. Recent technological developments have facilitated these lines of investigation by enabling direct measurement of the functional properties of single synaptic inputs...
Show moreIndividual neurons in the primary visual cortex respond selectively to different features of visual stimuli, such as spatial orientation or direction of motion. A longstanding goal in systems neuroscience has been to understand the transformations single cells perform as they integrate synaptic inputs to generate spiking output. Recent technological developments have facilitated these lines of investigation by enabling direct measurement of the functional properties of single synaptic inputs to neurons in the neocortex. It remains an outstanding question as to whether the tuning of single neocortical neurons can be predicted by their excitatory synaptic inputs. Here, I show that excitatory synaptic inputs exhibit significant functional diversity with respect to orientation and direction selectivity. I show that cells can use at least two strategies to overcome this functional diversity to achieve selective responses in the face of broadly tuned excitatory input: enhancing responses to the preferred stimuli and suppressing responses to the non-preferred stimuli. In the case of orientation selectivity, synaptic inputs cluster according to orientation preference and evoke local dendritic nonlinearities, thereby enhancing somatic responses to the preferred direction. For direction selectivity, cells receive excitatory synaptic inputs tuned to the preferred and null directions, but selectively suppress inputs tuned for the null direction to enhance direction selectivity. This suppression comes from direction-tuned GABAergic interneurons that make longrange, intercolumnar projections to enhance direction selectivity.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00004994
- Subject Headings
- Dissertations, Academic -- Florida Atlantic University
- Format
- Document (PDF)
- Title
- Quantifying the energetic cost of disorientation in loggerhead (Caretta caretta) and green (Chelonia mydas) sea turtle hatchlings.
- Creator
- Williams, Sean., Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
The photopollution of beaches caused by artificial light sources can interfere with sea turtle hatchlings' ability to orient properly towards the sea. Exhaustion due to extended disorientation crawling may then increase hatchling mortality. This study evaluated the energetic consequences of long-distance crawls in green and loggerhead sea turtle hatchlings. Turtles crawled for 200 m or 500 m on a treadmill, followed by a 30 minute evaluation of swim performance. Metabolic activity was...
Show moreThe photopollution of beaches caused by artificial light sources can interfere with sea turtle hatchlings' ability to orient properly towards the sea. Exhaustion due to extended disorientation crawling may then increase hatchling mortality. This study evaluated the energetic consequences of long-distance crawls in green and loggerhead sea turtle hatchlings. Turtles crawled for 200 m or 500 m on a treadmill, followed by a 30 minute evaluation of swim performance. Metabolic activity was quantified via measures of blood glucose, blood lactate, and oxygen consumption. No significant changes in metabolism resulted from long-distance crawling activity in loggerheads ; however, loggerheads rested for extended periods of time during the crawl trials, often unresponsive to stimuli. This behavior implies that loggerhead hatchlings would be vulnerable to predation or temperature stress due to exhaustion from extended periods of crawling. Further data is required to draw any significant conclusions about long-term disorientatin crawling in green hatchlings.
Show less - Date Issued
- 2012
- PURL
- http://purl.flvc.org/FAU/3356891
- Subject Headings
- Sea turtles, Nests, Protection, Sea turtles, Life cycles, Animal behavior, Predation (Biology)
- Format
- Document (PDF)
- Title
- An Introduced Primate Species, Chlorocebus Sabaeus, in Dania Beach, Florida: Investigating Origins, Demographics, and Anthropogenic Implications of an Established Population.
- Creator
- Williams, Deborah M., Detwiler, Kate, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Nonnative species are reshaping global ecosystems. The success of a nonnative species hinges on both biological and cultural variables. Primates represent a minority of nonnative species but warrant research to understand ecological implications and management solutions. The Florida Fish and Wildlife Conservation Commission recognizes three species of nonnative primates in Florida that include populations of rhesus macaques (Macaca mulatta) in Marion County, squirrel monkeys (Saimiri spp.) in...
Show moreNonnative species are reshaping global ecosystems. The success of a nonnative species hinges on both biological and cultural variables. Primates represent a minority of nonnative species but warrant research to understand ecological implications and management solutions. The Florida Fish and Wildlife Conservation Commission recognizes three species of nonnative primates in Florida that include populations of rhesus macaques (Macaca mulatta) in Marion County, squirrel monkeys (Saimiri spp.) in Broward County, and green monkeys (Chlorocebus sabaeus) in Broward County. This study focused on the Dania Beach C. sabaeus population. The goals of this study were to: 1) determine the geographical origins and species of the monkeys, 2) record demographics and determine population growth rate, 3) assess the public’s perception of monkeys, and 4) understand the influence of human provisioning on the population’s behavior and biology. Public surveys and direct field observations of social groups provided baseline data to show that unlike other introduced primates (e.g., macaques in Marion County and green monkeys in the Caribbean), the Dania Beach monkey population has strong public support and is at risk of extinction within the next 100 years.
Show less - Date Issued
- 2019
- PURL
- http://purl.flvc.org/fau/fd/FA00013279
- Subject Headings
- Nonnative species, Green monkey, Dania Beach (Fla.), Introduced species
- Format
- Document (PDF)
- Title
- Predicting leatherback sea turtle sex ratios using spatial interpolation of nesting beach temperatures.
- Creator
- Weston, Emily G., Wyneken, Jeanette, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Sex determination in leatherback sea turtles is directed primarily by the temperatures a clutch experiences during the middle third of development. Warmer temperatures tend to produce females will cooler temperatures yield males. Nest temperatures can vary spatially and temporally. During the 2010 and 2011 nesting seasons, this study estimated the hatchling sex ratio of leatherback sea turtles on Sandy Point National Wildlife Refuge (SPNWR), St. Croix, U.S. Virgin Islands. I measured sand...
Show moreSex determination in leatherback sea turtles is directed primarily by the temperatures a clutch experiences during the middle third of development. Warmer temperatures tend to produce females will cooler temperatures yield males. Nest temperatures can vary spatially and temporally. During the 2010 and 2011 nesting seasons, this study estimated the hatchling sex ratio of leatherback sea turtles on Sandy Point National Wildlife Refuge (SPNWR), St. Croix, U.S. Virgin Islands. I measured sand temperatures from May- August and across the spatial range of leatherback nesting habitat. I spatially interpolated those temperatures to create maps that predicted temperatures for all nests incubating on SPWNR. Nest temperatures were also directly measured and compared with predicted nest temperatures to validate the prediction model. Sexes of dead-in-nest hatchlings and full term embryos were used to confirm the sex-temperature response. The model showed that microclimatic variation likely impacts the production of both sexes on SPNWR.
Show less - Date Issued
- 2013
- PURL
- http://purl.flvc.org/fau/fd/FA0004071
- Subject Headings
- Leatherback turtle -- Habitat -- St. Croix -- Sandy Point National Wildlife Refuge (United States Virgin Islands), Loggerhead turtle -- Effect of temperature on, Sandy Point National Wildlife Refuge (United States Virgin Islands), Sea turtles -- Nests -- St. Croix -- Sandy Point National Wildlife Refuge (United States Virgin Islands), Sex determination, Genetic, Sex ratios, Vegetation dynamics
- Format
- Document (PDF)
- Title
- Habitat location and selection by the Sargassum crab Portunus sayi: the role of sensory cues.
- Creator
- West, Lorin E., Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
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The Sargassum community consists of a unique and idverse assemblage of fauna critical to pelagic food chains. Associated organisms presumably have adaptations to assist in finding Sargassum. This study investigated cues used for habitat location and selection by the Sargassum crab, Portunus sayi. Chemical detection trials were conducted with a two-chamber choice apparatus with Sargassum spp. and Thalassia testudinum as source odors. Visual detection trials (devoid of chemical cues) and...
Show moreThe Sargassum community consists of a unique and idverse assemblage of fauna critical to pelagic food chains. Associated organisms presumably have adaptations to assist in finding Sargassum. This study investigated cues used for habitat location and selection by the Sargassum crab, Portunus sayi. Chemical detection trials were conducted with a two-chamber choice apparatus with Sargassum spp. and Thalassia testudinum as source odors. Visual detection trials (devoid of chemical cues) and habitat selection trials were conducted in which crabs were given a choice of habitats. Results showed that P. sayi respoded to chemical odors from Sargassum spp. Crabs visually located habitats but did not visually distinguish between different habitats. In habitat selection trials, crabs selected Sargassum spp. over artificial Sargassum and T. testudinum. These results suggest that crabs isolated from Sargassum likely use chemoreception from longer distances ; within visual proximity of a potential patch, crabs use both chemical and visual information.
Show less - Date Issued
- 2012
- PURL
- http://purl.flvc.org/FAU/3356901
- Subject Headings
- Habitat (Ecology), Sargassum, Ecology, Marine chemical ecology, Chemoreceptors, Animal behavior, Animal communication, Portunus sayi, Ecology
- Format
- Document (PDF)
- Title
- A retrospective analysis of sea turtle nest depredation patterns at Canaveral National Seashore, Florida.
- Creator
- Welicky, Rachel., Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
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Nest predation can significantly reduce hatchling recruitment in sea turtle populations. This study uses 20 years of data from Canaveral National Seashore, Florida, which has pristine and altered beaches. Chi-square tests were used to determine if secondary predation events were related to the nest's primary depredation event. To determine if human beach use and nest predation are spatially or temporally linked, we ranked human beach use and examined predation frequency across all screened...
Show moreNest predation can significantly reduce hatchling recruitment in sea turtle populations. This study uses 20 years of data from Canaveral National Seashore, Florida, which has pristine and altered beaches. Chi-square tests were used to determine if secondary predation events were related to the nest's primary depredation event. To determine if human beach use and nest predation are spatially or temporally linked, we ranked human beach use and examined predation frequency across all screened and marked nests (n=40,441). Lastly, I quantified nest predation risk spatially and temporally. I found that primary predation increases the chance of a nest suffering subsequent predation. Primary and multiple predation events occurred with greater frequency in limited use areas and with lowest frequency in moderate use areas. Predation risk decreased by an average of 29.5% from 2000-2008. Nests deposited midseason were 9.8% more likely to be predated than nests deposited early or late.
Show less - Date Issued
- 2010
- PURL
- http://purl.flvc.org/FAU/2683130
- Subject Headings
- Predation (Biology), Wildlife managment, Sea turtles, Sea turtles, Nests
- Format
- Document (PDF)
- Title
- Maternal and alloparental discipline in Atlantic spotted dolphins (Stenella frontalis) in the Bahamas.
- Creator
- Weinpress, Meghan., Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
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Discipline was implemented by mothers and alloparent spotted dolphins (Stenella frontalis) mothers and alloparents on Little Bahama Bank, Bahamas. Disciplinarians were significantly more likely to be adults than juveniles. Although most disciplinarians were female, males were also observed to perform discipline. The recipients of discipline were male and female, and significantly more likely to be calves than juveniles. Pursuit, contact, and display behaviors were used in discipline, however...
Show moreDiscipline was implemented by mothers and alloparent spotted dolphins (Stenella frontalis) mothers and alloparents on Little Bahama Bank, Bahamas. Disciplinarians were significantly more likely to be adults than juveniles. Although most disciplinarians were female, males were also observed to perform discipline. The recipients of discipline were male and female, and significantly more likely to be calves than juveniles. Pursuit, contact, and display behaviors were used in discipline, however pursuit behaviors were most often observed. Variables such as age class, sex, and parity were not found to influence how discipline was implemented. The durations of all disciplinary pursuits were under thirty seconds, and successful pursuits had slightly shorter duration than unsuccessful pursuits. Disciplinarian success was not significantly influenced by age class, sex, parity, or behavior used.
Show less - Date Issued
- 2013
- PURL
- http://purl.flvc.org/fcla/dt/3361254
- Subject Headings
- Animal behavior, Behavior evolution, Atlantic mammals, Behavior, Parent-child relationships, Social behavior in animals, Discipline of children, Atlantic spotted dolphin
- Format
- Document (PDF)
- Title
- Phosphate-associated phenotype plasticity as a driver of cattail invasion in the sawgass-dominated Everglades.
- Creator
- Webb, James., Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
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In plants, phenotypic plasticity, the ability to morphologically adapt to new or broad environmental conditions, is a consequence of long-term evolutionary genetic processes. Thus, plants adapted to low phosphate (P) environments exhibit only limited plasticity to take advantage of nutrient enrichment, a global phenomenon in terrestrial and aquatic environments. In the face of anthropogenic P-enrichment, low nutrient adapted resident plant species are frequently displaced by species with high...
Show moreIn plants, phenotypic plasticity, the ability to morphologically adapt to new or broad environmental conditions, is a consequence of long-term evolutionary genetic processes. Thus, plants adapted to low phosphate (P) environments exhibit only limited plasticity to take advantage of nutrient enrichment, a global phenomenon in terrestrial and aquatic environments. In the face of anthropogenic P-enrichment, low nutrient adapted resident plant species are frequently displaced by species with high morphological and genetic plasticity. However, it remains unclear whether plasticity is systemically expressed across molecular, biochemical, physiological, and morphological processes that ultimately contribute to the root and shoot phenotypes of plants. In this study, we demonstrated high plasticity in root-borne traits of sawgrass (Cladium jamaicense), the dominant plant species of the P-impoverished Everglades, and counter the idea of inflexibility in low P adapted species. However, sawgras s expressed inflexibility in processes contributing to shoot phenotypes, in contrast to cattail, which was highly plastic in shoot characteristics vii in response to P enrichment. In fact, plasticity in cattail shoots is likely a function of its growth response to P that was globally regulated by P-availability at the level of transcription. Plasticity and inflexibility in the growth of both species also diverged in their allocation of P to the chloroplast for growth in cattail versus the vacuole for P storage in sawgrass. In the Everglades, anthropogenic P-enrichment has changed the environment from a P-limited condition, where plasticity in root-borne traits of sawgrass was advantageous, to one of light-competition, where plasticity in shoot-borne traits drives competitive dominance by cattail., We hypothesize that these shifts in plasticity competitive advantage from root to shoots has been a major driver of cattail expansion in the Everglades ecosystem. Further, this understanding of how natural plant species adapt and shift in response to nutrient availability could also be used a model system to optimize agricultural systems to increase efficiencies in food production and protect low nutrient adapted natural systems from cultural eutrophication.
Show less - Date Issued
- 2010, 2010
- PURL
- http://purl.flvc.org/FAU/2979377
- Subject Headings
- Ecosystem management, Vegatation dynamics, Phosphorous, Physiological transport, Biogeochemical cycles
- Format
- Document (PDF)