Euryhalinity In An Evolutionary Context,
2013
University of Connecticut - Storrs
Euryhalinity In An Evolutionary Context, Eric T. Schultz, Stephen D. Mccormick
EEB Articles
This chapter focuses on the evolutionary importance and taxonomic distribution of euryhalinity. Euryhalinity refers to broad halotolerance and broad halohabitat distribution. Salinity exposure experiments have demonstrated that species vary tenfold in their range of tolerable salinity levels, primarily because of differences in upper limits. Halotolerance breadth varies with the species’ evolutionary history, as represented by its ordinal classification, and with the species’ halohabitat. Freshwater and seawater species tolerate brackish water; their empirically-determined fundamental haloniche is broader than their realized haloniche, as revealed by the halohabitats they occupy. With respect to halohabitat distribution, a minority of species (<10%) are euryhaline. Habitat-euryhalinity is prevalent among basal actinopterygian fishes, is largely absent from orders arising from intermediate nodes, and reappears in the most derived taxa. There is pronounced family-level variability in the tendency to be halohabitat-euryhaline, which may have arisen during a burst of diversification following the Cretaceous-Palaeogene extinction. Low prevalence notwithstanding, euryhaline species are potent sources of evolutionary diversity. Euryhalinity is regarded as a key innovation trait whose evolution enables exploitation of new adaptive zone, triggering cladogenesis. We review phylogenetically-informed studies that demonstrate freshwater species diversifying from euryhaline ancestors through processes such as landlocking. These studies indicate that some euryhaline taxa are particularly susceptible to changes in halohabitat and subsequent diversification, and some geographic regions have been hotspots for transitions to freshwater. Comparative studies on mechanisms among multiple taxa and at multiple levels of biological integration are needed to clarify evolutionary pathways to, and from, euryhalinity.
Postcranial Description And Reconstruction Of The Varanodontine Varanopid Aerosaurus Wellesi (Synapsida: Eupelycosauria),
2013
California State University, San Bernardino
Postcranial Description And Reconstruction Of The Varanodontine Varanopid Aerosaurus Wellesi (Synapsida: Eupelycosauria), Valerie Ann Pelletier
Theses Digitization Project
The postcranial skeleton of the varanopid synapsid aerosaurus wellesi is reconstructed based on several specimens including partly articulated material of an apparently fully adult specimen. Comparisons are made with other known varanopid taxa, reaffirming its position as a basal varanondontine.
Variable Levels Of Atmospheric Oxygen Do Not Affect Microanatomy And Limb Bone Geometry In Alligator Mississippiensis,
2013
California State University, San Bernardino
Variable Levels Of Atmospheric Oxygen Do Not Affect Microanatomy And Limb Bone Geometry In Alligator Mississippiensis, Susan Lee Lujan
Theses Digitization Project
Striking changes in atmospheric oxygen levels have occured since the beginning of the Phanerozic 542 million years ago. Alligators belong to a clade of vertebrates with a long evolutionary history spanning much of this variability in atmospheric oxygen. An investigation into the effects of hypoxia and hyperoxia on skeletal growth and physiology in alligators may help to reconstruct the life history of archosaurs, explain patterns in the fossil record, and broaden our understanding of the processes underlying long term success of this clade.
Knockdown Of Vitellogenin By Rnai Increases Survivorship But Exhibits Similar Physiological Responses To Ovariectomy In Grasshoppers,
2013
University of North Florida
Knockdown Of Vitellogenin By Rnai Increases Survivorship But Exhibits Similar Physiological Responses To Ovariectomy In Grasshoppers, Alicia G. Linquist
UNF Graduate Theses and Dissertations
Reduced reproduction has been shown to increase lifespan in many animals, yet the mechanisms behind this trade-off are mostly unknown. A previous study has shown that in the lubber grasshopper, Romalea microptera, ovariectomized (OVX) individuals have a 30% increase in lifespan relative to controls (Sham). In a separate study, an increase in fat body mass and a halting of ovarian growth were seen upon reduction of vitellogenin transcript via RNAi (VgRNAi). These data suggest that VgRNAi increases lifespan through the trade-off between reproduction and longevity and animals with combined ovariectomy and VgRNAi, might show additive physiological responses. In this …
Population Genetics And Ecology Of Regional Malaria Vectors In Amazonian Brazil,
2013
University at Albany, State University of New York
Population Genetics And Ecology Of Regional Malaria Vectors In Amazonian Brazil, Sascha Naomi Mckeon
Legacy Theses & Dissertations (2009 - 2024)
Species complexes are common among anopheline mosquitoes, but only some members of complexes are disease vectors. Research involving overall patterns of divergence, phylogenetic relationships and population structure is partly driven by the operational need to be able to reliably distinguish component taxa that may be involved in malaria transmission. Anopheles triannulatus, An. nuneztovari and An. albitarsis are broadly distributed species complexes that contain local and regionally important malaria vectors, whose genetic diversity has been largely overshadowed by studies involving An. darlingi, the principal vector of Central and South America. I have analyzed the ecological suitability of habitats and geographical ranges …
Mechanisms Of Nitrogenous Waste Excretion During The Complex Life Cycle Of The Sea Lamprey (Petromyzon Marinus),
2013
Wilfrid Laurier University
Mechanisms Of Nitrogenous Waste Excretion During The Complex Life Cycle Of The Sea Lamprey (Petromyzon Marinus), James M. Neal Mr.
Theses and Dissertations (Comprehensive)
Sea lampreys (Petromyzon marinus) are a phylogenetically ancient jawless fish, with a multi-staged life cycle characterized by a prolonged suspension-feeding larval stage, which is followed by metamorphosis into parasitic lampreys that feed on the protein-rich blood of fishes. The switch from a nutrient poor to protein-rich diet in the sea lamprey is associated with an increased capacity to deaminate excess amino acids and to excrete ammonia and urea following metamorphosis. The focus of this thesis was to determine if changes in nitrogenous waste transporter protein abundance facilitate ammonia and urea excretion during different stages of the sea lamprey …
Comparative Sugar Transport By Crustacean Hepatopancreas And Intestine,
2013
University of North Florida
Comparative Sugar Transport By Crustacean Hepatopancreas And Intestine, Ada Duka
UNF Graduate Theses and Dissertations
Glucose is transported in crustacean hepatopancreas and intestine by Na+-dependent co-transport, while Na+-dependent D-fructose influx has only been described for the hepatopancreas. It is still unclear if the two sugars are independently transported by two distinct cotransporter carrier systems. In this study lobster (Homarus americanus) hepatopancreas brush border membrane vesicles (BBMV) were used to characterize, in detail, the cation-dependency of both D-[3H] glucose and D-[3H] fructose influxes, while in vitro perfused intestines were employed to determine the nature of cation-dependent sugar transport in this organ. Over the sodium concentration range …
The Cost Of Ethanol Synthesis During Recovery From Exhaustive Exercise In Grass Carp (Ctenopharyngodon Idella),
2012
The University of Western Ontario
The Cost Of Ethanol Synthesis During Recovery From Exhaustive Exercise In Grass Carp (Ctenopharyngodon Idella), Simon A. Bradford
Electronic Thesis and Dissertation Repository
Grass carp (Ctenopharyngodon idella) reduce white muscle glycogen (~14 µmol glucosyl units/g wet tissue) in response to exhaustive exercise. This reduction results in a small increase in muscle lactate (~9 µmol/g wet tissue) and a larger increase in muscle ethanol (~30 µmol/g wet tissue). Tissue-specific and whole-body measures of glycogen, ethanol and lactate confirm that ethanol is the major “anaerobic” glycolytic end-product. Additionally, while peak muscle and blood ethanol levels occur immediately post-exercise, the excretion of ethanol to the environment is delayed, occurring over a 30-minute period beginning ~105 minutes following exercise. As the total amount of ethanol …
Cold Tolerance Of Each Life Stage Of The Sub-Alpine Willow Leaf Beetle, Chrysomela Aeneicollis,
2012
The University of Western Ontario
Cold Tolerance Of Each Life Stage Of The Sub-Alpine Willow Leaf Beetle, Chrysomela Aeneicollis, Evelyn C. Boychuk
Electronic Thesis and Dissertation Repository
To understand the potential effects of climate change on the sub-alpine willow leaf beetle, the cold tolerance strategy and mechanisms involved in cold tolerance were investigated for all life stages. Microhabitat choice and microclimate temperatures within each microhabitat were related to median lethal temperature for each life stage. Summer active and quiescent adults are freeze tolerant, eggs and pupae are freeze avoidant and all larval stages are chill susceptible. Quiescent adults accumulated the highest concentration of glycerol (~24 mM) and haemolymph osmolality (875 mOsm). Haemolymph from pupae had angular crystals suggestive of antifreeze agent activity, but this was absent in …
Ion Homeostasis And Variation In Low Temperature Performance In The Fall And Spring Field Crickets (Orthoptera: Gryllidae),
2012
The University of Western Ontario
Ion Homeostasis And Variation In Low Temperature Performance In The Fall And Spring Field Crickets (Orthoptera: Gryllidae), Litza E. Coello Alvarado
Electronic Thesis and Dissertation Repository
Low temperature performance affects the geographical distribution of insects. The lower critical temperature limits of chill-susceptible insects are likely determined by failure of ion and water balance at low temperature. I used phenotypic plasticity in the cold tolerance of Gryllus pennsylvanicus, and the naturally higher cold tolerance of Gryllus veletis to test the hypothesis that variation in low temperature performance is accompanied by variation in ion and water homeostasis at low temperatures. Low temperature acclimation and cold adaptation enhanced performance at low temperatures. Groups with higher cold tolerance had an enhanced ability to prevent or mitigate the migration of hemolymph …
Environmental Physiology Of Flight In Migratory Birds,
2012
The University of Western Ontario
Environmental Physiology Of Flight In Migratory Birds, Alexander R. Gerson
Electronic Thesis and Dissertation Repository
Migratory birds complete amazing journeys between their breeding and wintering grounds. Each journey comprises a series of flights that last hours to days, followed by stopovers where fuel stores are replenished. Despite the long flights undertaken by migratory birds, where respiratory water losses are high for extended periods of time, birds are not dehydrated after flight. My studies demonstrate that birds maintain hydration by modulating rates of endogenous water production in response to rates of water loss. In resting, water restricted house sparrows (Passer domesticus) I used quantitative magnetic resonance body composition analysis (QMR) and hygrometry to demonstrate that stressed …
Rapid Inversion: Running Animals And Robots Swing Like A Pendulum Under Ledges,
2012
University of California - Berkeley
Rapid Inversion: Running Animals And Robots Swing Like A Pendulum Under Ledges, Jean-Michel Mongeau, Brian Mcrae, Ardian Jusufi, Paul Birkmeyer, Aaron M. Hoover, Ronald Fearing, Robert J. Full
Aaron M. Hoover
Escaping from predators often demands that animals rapidly negotiate complex environments. The smallest animals attain relatively fast speeds with high frequency leg cycling, wing flapping or body undulations, but absolute speeds are slow compared to larger animals. Instead, small animals benefit from the advantages of enhanced maneuverability in part due to scaling. Here, we report a novel behavior in small, legged runners that may facilitate their escape by disappearance from predators. We video recorded cockroaches and geckos rapidly running up an incline toward a ledge, digitized their motion and created a simple model to generalize the behavior. Both species ran …
Phylogeny Of Panthera, Including P. Atrox, Based On Cranialmandibular Characters,
2012
East Tennessee State University
Phylogeny Of Panthera, Including P. Atrox, Based On Cranialmandibular Characters, Leigha M. King
Electronic Theses and Dissertations
Over the past 20 years both morphological and molecular phylogenies have been proposed for extant and extinct members of the family Felidae. However, there remain several discrepancies, particularly within the genus Panthera and the position of Panthera atrox. Consequently, morphologic characters from the skull and dentary were analyzed within Panthera (including all extant and one extinct taxa) to gain a better understanding of pantherine phylogeny. Multiple specimens of each taxon were analyzed, including: P. leo, P. tigris, P. onca, P. pardus , Uncia uncia, and Neofelis nebulosa. Four outgroups were used; Crocuta crocuta, Metailurus ssp., Proailurus lemanensis …
The Time-Course Of The Effects Of Growth Hormone During Zebrafish (Danio Rerio) Auditory Hair Cell Regeneration,
2012
Western Kentucky University
The Time-Course Of The Effects Of Growth Hormone During Zebrafish (Danio Rerio) Auditory Hair Cell Regeneration, Yajie Wang
Masters Theses & Specialist Projects
Growth hormone (GH) was upregulated in the zebrafish inner ear following sound exposure in a previous study. To identify the specific role of GH in hair cell regeneration and the possible cellular mechanisms of this regeneration, groups of zebrafish were divided into baseline (no sound exposure, no injection), buffer-injected and GH-injected groups. Buffer- and GH-injected fish were exposed to a 150 Hz tone at a source level of 179 dB re 1 μPa root mean squared (RMS) for 36 h. Phalloidin-staining was used to assess the effects of GH on hair cell bundle density; BrdU-labeling was used to assess the …
Dynamics Of Fat And Lean Mass In Refuelling Migrant Passerines Measured Using Quantitative Magnetic Resonance,
2012
The University of Western Ontario
Dynamics Of Fat And Lean Mass In Refuelling Migrant Passerines Measured Using Quantitative Magnetic Resonance, Lisa V. Kennedy
Electronic Thesis and Dissertation Repository
Although fat deposition during stopover in migrating passerine birds has been extensively studied, changes in lean mass during refuelling are not well understood. I used quantitative magnetic resonance (QMR) analysis to measure the deposition of fat and lean mass for both recaptured and single capture migrant passerines in spring and fall at Long Point, Ontario. Both the recapture analysis and single capture regression analysis indicated a substantial contribution of lean mass to overall increases in total body mass. Some of the variation in the relative deposition of fat and lean mass was explained by sex, age and season. I then …
Overwintering Energetics Of Lepidoptera: The Effects Of Winter Warming And Thermal Variability.,
2012
University of Western Ontario
Overwintering Energetics Of Lepidoptera: The Effects Of Winter Warming And Thermal Variability., Caroline M. Williams
Caroline M Williams
Winter temperatures are changing rapidly, and although winter warming reduces cold stress for overwintering ectotherms, temperature-mediated increases in metabolic rate can decrease fitness in dormant insects by increasing consumption of energy reserves. Increases in thermal variability also increase energetic demands, due to non-linear thermal response curves. My objective was to quantify the negative effects of winter warming and increases in thermal variability on a range of Lepidopteran species. As overwintering insects rely on lipid catabolism, accurate lipid measurement is central to my dissertation; so I first compared four methods of lipid quantification; concluding thin layer chromatography was the only method …
Temperature Effects On Growth And Stress Physiology Of Brook Trout: Implications For Climate Change Impacts On An Iconic Cold-Water Fish,
2012
University of Massachusetts Amherst
Temperature Effects On Growth And Stress Physiology Of Brook Trout: Implications For Climate Change Impacts On An Iconic Cold-Water Fish, Joseph G. Chadwick Jr
Masters Theses 1911 - February 2014
Despite the threat of climate change, the physiological mechanisms by which temperature drives the distribution of species are unclear. Here we used chronic temperature exposures to determine that the upper limit for positive growth in the eastern brook trout (Salvelinus fontinalis) is 23.4 °C. Additionally, brook trout exposed to daily temperature oscillations of 8 °C, around a mean of 21 °C, exhibited growth rates that were 43 and 35% lower by length and weight respectively, than in constant 21 °C controls. Limitations in growth were associated with increases in indicators of the physiological stress response. Individuals exposed to …
Foraging And Roosting Behaviors Of Rafinesque's Big-Eared Bat (Corynorhinus Rafinesquii) At The Northern Edge Of The Species Range,
2012
University of Kentucky
Foraging And Roosting Behaviors Of Rafinesque's Big-Eared Bat (Corynorhinus Rafinesquii) At The Northern Edge Of The Species Range, Joseph S. Johnson
Theses and Dissertations--Animal and Food Sciences
Bat populations in the eastern United States are currently declining at unprecedented rates as a result of habitat loss, commercial wind energy development, and white-nose syndrome. Effective conservation of these declining populations requires knowledge of several aspects of summer and winter ecology, including daytime habitat use (day-roost selection and social behaviors), nocturnal habitat use (foraging habitat selection, prey selection, and prey abundance), and winter hibernation (torpor) patterns. This dissertation addresses these questions for Rafinesque’s big-eared bat (Corynorhinus rafinesquii), a species of conservation concern in the southeastern United States. Kentucky represents the northern edge of the range of Rafinesque’s …
Salinity Preference Of Alaskan Threespine Stickleback: Test For Divergence In Halotaxis Between Ancestral And Landlocked Populations,
2012
University of Connecticut - Storrs
Salinity Preference Of Alaskan Threespine Stickleback: Test For Divergence In Halotaxis Between Ancestral And Landlocked Populations, David Fryxell, Eric T. Schultz
EEB Articles
Glacial retreat during the Pleistocene caused landlocking of anadromous Alaskan threespine stickleback, Gasterosteus aculeatus, furnishing a natural ‘experiment’ in osmoregulatory divergence. The objective of this study was to assess the effects of individual acclimation and population divergence on salinity preference. Full-sibling families of marine, anadromous, and freshwater-landlocked populations of stickleback were reared in common environments until 3 weeks post-hatch, then were split and acclimated to low or high salinity. At 6 to 8 weeks of age the six experimental groups were tested for salinity preference in a tank that offers fish a choice of compartments with different salinities arranged …
Variation In Gene Transcript Profiles Of Two V1a-Type Arginine Vasotocin Receptors Among Sexual Phases Of Bluehead Wrasse (Thalassoma Bifasciatum),
2012
SelectedWorks
Variation In Gene Transcript Profiles Of Two V1a-Type Arginine Vasotocin Receptors Among Sexual Phases Of Bluehead Wrasse (Thalassoma Bifasciatum), Sean C. Lema, Melissa A. Slane, Kelley E. Salvesen, John Godwin
Sean Lema
The neurohypophyseal hormone arginine vasotocin (AVT) mediates behavioral and reproductive plasticity in vertebrates, and has been linked to the behavioral changes associated with protogyny in the bluehead wrasse (Thalassoma bifasciatum). In this study, we sequenced full-length cDNAs encoding two distinct V1a-type AVT receptors (v1a1 and v1a2) from the bluehead wrasse, and examined variation in brain and gonadal abundance of these receptor transcripts among sexual phases. End point RT-PCR revealed that v1a1 and v1a2 transcripts varied in tissue distribution, with v1a1 receptor mRNAs at greatest levels in the telencephalon, hypothalamus, optic tectum, cerebellum and testis, and v1a2 receptor transcripts most abundant …
