Biology Commons^™

Size And Temperature In The Evolution Of Fish Life Histories, Eric Charnov, James Gillooly

Biology Faculty & Staff Publications

Body size and temperature are the two most important variables affecting nearly all biological rates and times, especially individual growth or production rates. By favoring an optimal maturation age and reproductive allocation, natural selection links individual growth to the mortality schedule. A recent model for evolution of life histories for species with indeterminate growth, which includes most fish, successfully predicts the numeric values of two key dimensionless numbers and the allometry of the average reproductive allocation versus maturation size across species. Here we use this new model to predict the relationships of age-at-maturity, adult mortality and reproductive effort to environmental …

Epidemiology Of Ustilago Bullata Berk. On Bromus Tectorum L. And Implication For Biological Control, Toupta Boguena

Theses and Dissertations

The seedling-infecting pathogen Ustilago bullata Berk. is a naturally occurring biological control agent for cheatgrass (Bromus tectorum L.). The effects of temperature and nutrients on pathogen teliospore germination behavior and the effects of temperature on host seed germination were examined. The effects of temperature on sporidial proliferation, host infection in a temperature-controlled environment and in a field setting for eight populations were investigated. The infection success of Ustilago bullata on Bromus tectorum in cultivated fields as a function of seeding date, inoculation method, inoculum density, supplemental watering, and litter was also investigated. Teliospores germinated faster on potato dextrose agar than …

Two Arabidopsis Circadian Oscillators Can Be Distinguished By Differential Temperature Sensitivity, Todd P. Michael, Patrice A. Salome, C. Robertson Mcclung

Dartmouth Scholarship

Circadian rhythms are widespread in nature and reflect the activity of an endogenous biological clock. In metazoans, the circadian system includes a central circadian clock in the brain as well as distinct clocks in peripheral tissues such as the retina or liver. Similarly, plants have distinct clocks in different cell layers and tissues. Here, we show that two different circadian clocks, distinguishable by their sensitivity to environmental temperature signals, regulate the transcription of genes that are expressed in the Arabidopsis thaliana cotyledon. One oscillator, which regulates CAB2 expression, responds preferentially to light–dark versus temperature cycles and fails to respond to …

Thermal Time: Body Size, Food Quality And The 10c Rule, Eric Charnov, James Gillooly

Biology Faculty & Staff Publications

Developmental rates of ectotherms (y) are often linearly related to temperature (Tc in C) within some biologically relevant range of temperatures as y = (1/S)(Tc - Tb), where Tb is the estimated temperature at zero development, and the thermal constant S is the development time multiplied by the temperature above Tb (i.e. degree days above Tb). Among similar species, it has been widely shown that S and Tb are negatively related across environments, that S is positively related to body size, and that Tb is independent of body size but increases with mean environmental temperature. Here we present a model …

Bergmann's Rule In Ectotherms: A Test Using Freshwater Fishes, Mark C. Belk, Derek D. Houston

Faculty Publications

Understanding patterns of variation in body size within and among species is a central question in evolutionary ecology (Schlichting and Pigliucci 1998). The most well known pattern of variation in body size is Bergmann's rule (Bergmann 1847; Mayr 1956). The intraspecific version of Bergmann's rule holds that within endothermic species, body size increases with increasing latitude (or decreasing temperature; Blackburn et al. 1999; Ashton et al. 2000). In general, mammals conform to this rule (Ashton et al. 2000).

Mad2 And Bubr1 Function In A Single Checkpoint Pathway That Responds To A Loss Of Tension, Katie Shannon, Julie C. Canman, Edward D. Salmon

Biological Sciences Faculty Research & Creative Works

The spindle checkpoint monitors microtubule attachment and tension at kinetochores to ensure proper chromosome segregation. Previously, PtK1 cells in hypothermic conditions (23°C) were shown to have a pronounced mitotic delay, despite having normal numbers of kinetochore microtubules. At 23°C, we found that PtK1 cells remained in metaphase for an average of 101 min, compared with 21 min for cells at 37°C. The metaphase delay at 23°C was abrogated by injection of Mad2 inhibitors, showing that Mad2 and the spindle checkpoint were responsible for the prolonged metaphase. Live cell imaging showed that kinetochore Mad2 became undetectable soon after chromosome congression. Measurements …

Effects Of Temperature, Epinephrine And Ca2+ On The Hearts Of Yellowfin Tuna (Thunnus Albacares), Jason M. Blank, Jeffery M. Morrissette, Peter S. Davie, Barbara A. Block

Biological Sciences

Tuna are endothermic fish with high metabolic rates, cardiac outputs and aerobic capacities. While tuna warm their skeletal muscle, viscera, brain and eyes, their hearts remain near ambient temperature, raising the possibility that cardiac performance may limit their thermal niches. We used an in situ perfused heart preparation to investigate the effects of acute temperature change and the effects of epinephrine and extracellular Ca²⁺ on cardiac function in yellowfin tuna (Thunnus albacares). Heart rate showed a strong temperature-dependence, ranging from 20 beats min^-1 at 10 °C to 109 beats min^-1 at 25 °C. Maximal stroke …

Effects Of Size And Temperature On Developmental Time, James Gillooly, Eric Charnov, Geoffrey West, Van Savage, James Brown

Biology Faculty & Staff Publications

Body size and temperature are the two most important variables affecting nearly all biological rates and times. The relationship of size and temperature to development is of particular interest, because during ontogeny size changes and temperature often varies. Here we derive a general model, based on first principles of allometry and biochemical kinetics, that predicts the time of ontogenetic development as a function of body mass and temperature. The model fits embryonic development times spanning a wide range of egg sizes and incubation temperatures for birds and aquatic ectotherms (fish, amphibians, aquatic insects and zooplankton). The model also describes nearly …

Effects Of Photoperiod And Temperature On Growth And Reproductive Organ Mass In Adult Male Mongolian Gerbils, Meriones Unguiculatus, Bülent Gündüz

Turkish Journal of Biology

Rates of growth and sexual maturation of Mongolian gerbils vary in response to photoperiod. Previous work has shown that the responses of the testes and body weight of juvenile and adult gerbils are influenced not only by the photoperiods but also by other factors. The present work sought to determine if Mongolian gerbils alter body mass, body composition and/or reproductive organ mass in response to different photoperiods and temperatures. Male Mongolian gerbils were raised under long (14L) or short (10L) photoperiods from 26 days of age. Photoperiods did not affect body mass and body length. Temperature affected body mass only …

Effects Of Size And Temperature On Metabolic Rate, James Gillooly, James Brown, Geoffrey West, Van Savage, Eric Charnov

Biology Faculty & Staff Publications

We derive a general model, based on principles of biochemical kinetics and allometry, that characterizes the effects of temperature and body mass on metabolic rate. The model fits metabolic rates of microbes, ectotherms, endotherms (including those in hibernation), and plants in temperatures ranging from 0 to 40C. Mass - and temperature - compensated resting metabolic rates of all organisms are similar: The lowest (for unicellular organisms and plants) is separated from the highest (for endothermic vertebrates) by a factor of about 20. Temperature and body size are primary determinants of biological time and ecological roles.

Virginia's Pfiesteria Monitoring Program: Water Quality, Roger K. Everton, Wick T. Harlan, Jonathan W. Priest, Mark S. Alling

Virginia Journal of Science

During the summer and early fall of 1998, 34 estuarine stations in Virginia were sampled for Pfiesteria like organisms (PLOs) and associated water quality conditions. Stations were sampled either bimonthly (20 stations) or monthly (14 stations) from June to October 1998. At each station, a set of live and Lugol' s preserved samples were collected for presumptive counts of PLOs and water quality conditions were determined. Water quality parame­ters measured included standard field parameters, nutrients (total, dissolved, and particulate), chlorophyll a, and conventional water quality indicators. Although PLOs were relatively low in 1998 as compared to 1997, presump­tive PLO counts …

Modeling Nutrient And Plankton Processes In The California Coastal Transition Zone: 3. Lagrangian Drifters, J. R. Moisan, Eileen E. Hofmann

CCPO Publications

Two types of numerical Lagrangian drifter experiments were conducted, using a set of increasingly complex and sophisticated models, to investigate the processes associated with the plankton distributions in the California coastal transition zone (CTZ). The first experiment used a one-dimensional (1-D; vertical) time-dependent physical-bio-optical model, which contained a nine-component food web. Vertical velocities, along the track of simulated Lagrangian drifters, derived from a three-dimensional (3-D), primitive equation circulation model developed to simulate the flow observed within the CTZ; were used to parameterize the upwelling and downwelling processes. The second experiment used 880 simulated Lagrangian drifters from a 3-D primitive equation …

Determinants Of Weddellite Formation: Chondroitin Sulfates And Citrate Determine Weddellite Formation In Vitro, Kookmin M. Kim

Scanning Microscopy

In synthetic urine (SU), addition of oxalate tends to form monohydrates of calcium oxalate. However, addition of oxalate to natural urine preferably forms calcium oxalate dihydrate (COD). Urine apparently contains a determinant for COD formation. To identify the determinant, the effects of pH, temperature, oxalate, calcium, urate, citrate, magnesium, sulfate and chondroitin sulfates (CS) on calcium oxalate crystal formation were studied. Lower temperatures, higher oxalate concentrations and higher pH favored COD formation in a SU. Mixed CS in the presence of citrate were the most decisive determinant of COD formation. Substitution of CS for agar and gelatin produced similar results, …

Reversible And Irreversible Effects Of Temperature On Amelogenesis Of Hamster Tooth Germs In Vitro, J. H. M. Wöltgens, D. M. Lyaruu, Th. J. M. Bervoets, A. L. J. J. Bronckers

Scanning Microscopy

Hamster first hamster molar tooth germs in early secretory stage of amelogenesis were cultured for one day in vitro at 6°C, 22°C, 37°C or 45°C in the presence of ³H-proline, ⁴⁵Ca and ³²P-orthophosphate. Other explants were cultured without these labels and after culture examined by histology. The highest temperature tested was lethal to the explants, decreased total dry weight and rapidly increased total uptake of the radio-labelled mineral ions, probably merely due to physicochemical modification of the existing preculture minerals. Optimal synthesis and secretion of amelogenins were measured at physiological temperature (37°C). Effects of exposure to both …

Topographic Evolution In The Atomic Scale Growth And Erosion Continuum, G. Carter, I. V. Katardjiev, M. J. Nobes, J. L. Whitton

Scanning Microscopy

This review gives a detailed survey of the range of fascinating surface features which develop under growth or erosion conditions under the combined influence of thermal and more energetic atomic particle fluxes. Collisionally induced atomic ejection and migration, and thermally and radiation induced atom and defect diffusion processes are outlined and their relevance to topographic initiation and evolution explored. A range of experimental observations of surface feature elaboration is discussed from net growth to net erosion conditions and models for their explanation are considered. It is concluded that while much data have been accumulated, much of these have been in …

The Cytoskeletal System Of Nucleated Erythrocytes. I. Composition And Function Of Major Elements, William D. Cohen, Diana Bartelt, Richard Jaeger, George M. Langford, Iris Nemhauser

Biology - All Scholarship

We have studied the dogfish erythrocyte cytoskeletal system, which consists of a marginal band of microtubules (MB) and trans-marginal band material (TBM). The TBM appeared in whole mounts as a rough irregular network and in thin sections as a surface-delimiting layer completely enclosing nucleus and MB. In cells incubated at 0 degrees C for 30 min or more, the MB disappeared but the TBM remained. MB reassembly occurred with rewarming, and was inhibited by colchicine. Flattened elliptical erythrocyte morphology was retained even when MBs were absent. Total solubilization of MB and TBM at low pH, or dissolution of whole anucleate …

Role Of Gulf Stream Frontal Eddies In Forming Phytoplankton Patches On The Outer Southeastern Shelf, James A. Yoder, Larry P. Atkinson, Thomas N. Lee, Hongsuk H. Kim, Charles R. Mcclain

CCPO Publications

Continuous surface mapping of temperature, salinity, and chlorophyll along a 300-km segment of the Gulf Stream cyclonic front defined the spatial scales of a large diatom patch that persisted throughout a 10-day study. The patch was localized in the upwelled cold core of a Gulf Stream frontal eddy centered over the 200-m isobaths off Jacksonville, Florida, in April 1979. The µ g liter^-1 surface chlorophyll isopleth enclosed an area >1,000km² with an alongshore dimension of 130km. Surface chlorophyll exceeded 5µg liter^-1 within the upwelled cold core of the eddy, 10-100X higher than concentrations in Gulf Stream or …

Motility Of The Microtubular Axostyle In Pyrsonympha, George M. Langford, Shinya Inoué

Biology - All Scholarship

The rhythmic movement of the microtubular axostyle in the termite flagellate, Pyrsonympha vertens, was analyzed with polarization and electron microscopy. The protozoan axostyle is birefringent as a result of the semi-crystalline alignment of approximately 2,000 microtubules. The birefringence of the organelle permits analysis of the beat pattern in vivo. Modifications of the beat pattern were achieved with visible and UV microbeam irradiation. The beating axostyle is helically twisted and has two principal movements, one resembling ciliary and the other flagellar beating. The anterior portion of the beating axostyle has effective and recovery phases with each beat thereby simulating the flexural …

Temperature Effect On Leaf Water Potential Measurements, Rex J. Prosser

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Silver foil psychrometers were used to monitor water potential in different portions of maize leaves which were subjected to temperature gradients. The psychrometers were preliminarily calibrated over standard NaCI solutions at temperatures ranging from 5°C to 45°C in an aluminum plate apparatus designed to provide uniform temperatures within each psychrometer even while overall temperature was changing. Based on the calibrations, empirical temperature correction equations were derived and used to correct psychrometer readings at different temperatures to equivalent values at 25°C. Temperatures on a single maize leaf were varied by placing the long leaf through an insulated box with several compartments …

Factors Influencing Population Growth Of Tribolium Brevicornis In The Laboratory, Amin Gulla

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

To determine the effect of the factors of the environment (temperature, relative humidity, and food) on the population growth of Tribolium brevicornis, different levels of temperatures from 17.5°C - 37.5°C were used. Effect of these IeveIs of temperatures was tested upon both pre-embryonic and post-embryonic development. No hatching occurred at 17.5°C, but the threshold temperature (the minimum temperature for the development) was just before 17.5°C. The optimum temperature for the embryonic development was found to be between 32.5°C - 35°C.

With the use of the saturated salt solution according to Buxton (1931) and Buxton and Melanby (1934), certain humidity …

Sex-Linkage In Drosophila Melanogaster With Mention Of Mutation Factors, D. Wilkins Kirkpatrick

Biology Honors Papers

This 14 page thesis describes experiments conducted to observe sex-linked traits in flies as well as causes of mutations in the chromosomes.

Regeneration Experiments With Planaria Maculata, Frank J. Tornetta

Biology Honors Papers

This 25 page thesis discusses experiments to determine the effect of temperature on the rate of regeneration in planaria and to find the comparative rate of growth of sagittal, transverse and oblique sections.