Biology Commons^™

The Origins Of The Neutral Theory Of Molecular Evolution, Michael Dietrich

Dartmouth Scholarship

No abstract provided.

Reaction Norms For Age And Size At Maturity In Response To Temperature: A Puzzle For Life Historians., D. Berrigan, Eric Charnov

Biology Faculty & Staff Publications

Ectotherms mature later at smaller size when growth rates are lowered by reductions in food quality but they mature later at larger sizes when growth rate is lowered by reductions in temperature. We argue that this general pattern has been neglected by life history theorists and suggest that an explanation for these strikingly different responses to two environmental cues might be found by considering correlations between the growth coefficient of the Bertalanffy equation and asymptotic size in a model for the evolution of age and size at maturity.

New And Interesting Records Of Birds From A Dry Forest Reserve In South-West Ecuador, Karl S. Berg

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

La reserva forestal Cerro Blanco es una de las pocas áreas protegidas con más de 200 ha de bosque seco sobre el oeste ecuatoriano. Aunque existen listas de registros de aves en la reserva, con frecuencia no se conocen las fechas ni localidades en que fueron tomados. De otro lado, esta información no incluye observaciones de algunas de las partes de más difícil acceso en la reserva, ni muestra con precisión las diferentes altitudes, los tipos de bosques o las estaciones. Una información más amplia será cada vez más importante para la conservación y manejo de la vida silvestre de …

Characterization Of The Unique Intron - Exon Junctions Of Euglena Gene(S) Encoding The Polyprotein Precursor To The Light-Harvesting Chlorophyll A/B Binding Protein Of Photosystem Ii, Umesh Shyamsunder Muchhal, Steven D. Schwartzbach

School of Biological Sciences: Faculty Publications

The precursor to the Euglena light harvesting chlorophyll a/b binding protein of photosystem 11 (LHCPII) Is a polyprotein containing multiple copies of LHCPII covalently joined by a decapeptide linker. cDNA and genomic clones encoding the 5 and 3' end of a 6.6 kb LHCPII mRNA were sequenced. A 3.1 kb genomic region encoding 1.05 kb of the 5' end of LHCPII mRNA contains 4 introns. A 7.6 kb genomic region encoding 3.3 kb of the 3' end of LHCPII mRNA contains 10 introns. The 5' and 3' ends of the 14 Identified Euglena introns lacked the conserved dinucleotides (5'-GT and …

Enhanced Competitiveness Of Tomato Bushy Stunt Virus Defective Interfering Rnas By Segment Duplication Or Nucleotide Insertion, K. Andrew White, T. Jack Morris

School of Biological Sciences: Faculty Publications

We have analyzed atypical tomato bushy stunt virus defective interfering (DI) RNA species which accumulated during a passage series in protoplasts. We present a rationale for the order of appearance of these molecules and show, using competition assays, that either segment duplication or single nucleotide insertion can enhance DI RNA competitiveness. Possible mechanisms for the introduction of the modifications observed in these DI RNAs are discussed.

Terrapene Carolina Carolina, Joseph C. Mitchell, Rafael O. De Sá

Biology Faculty Publications

TERRAPENE CAROLINA CAROLINA (Eastern Box Turtle). REPRODUCTION. Female Terrapene carolina containing oviductal eggs have been recorded in Virginia from 26 May to 25 July (Mitchell, in press. The Reptiles of Virginia. Smithsonian Inst. Press, Washington, D.C.). Other reports of reproduction in Terrapene (see list in Ernst and McBreen 1991. Cat. Amer. Amphib. Rept. 512.1-512.13) indicate that nesting occurs in late spring and early summer throughout its range.

What Are Squirrels Hiding, Michael Steele, Peter D. Smallwood

Biology Faculty Publications

The half-eaten acorns of squirrels are clues to their complex relationship with oaks. The special relationship between squirrels and acorns is examined.

Ecology Of The Spotted Turtle, Clemmys Guttata At The Western Range Limit, Thomas P. Wilson

Masters Theses

No abstract provided.

Per-Like Immunoreactive Neurons Within The Brain Of Xenopus Innervate Both The Retina And Pineal Organ, J. M. Garcia-Fernandez, Kathleen King Siwicki, R. G. Foster

Biology Faculty Works

No abstract provided.

Considerations For Evaluating Ultraviolet Radiation-Induced Genetic Damage Relative To Antarctic Ozone Depletion, Deneb Karentz

Biology Faculty Publications

Springtime ozone depletion over the Antarctic results in increased UVB in local marine environments. It has been established that decreases in primary productivity occur with decreases in ozone concentrations, but the impact of increased UVB on the functioning and stability of the ecosystem has not yet been determined. Very little has been done to evaluate the potential for genetic damage caused by the increase in UVB, and this type of damage is most significant relative to the fitness and maintenance of populations. An essential problem in evaluating genotoxic effects is the lack of appropriate techniques to sample and quantify genetic …

Innervation Patterns In Neuromasts Of The Mottled Sculpin, Cottus Bairdi, Jie He

Master's Theses

No abstract provided.

Morphometry Of Growth In Hatchling Striped Plateau Lizards (Iguanidae: Sceloporus Virgatus), Geoffrey R. Smith

Faculty Publications

No abstract provided.

Modeling Daily Production Of Aquatic Macrophytes From Irradiance Measurements: A Comparative Analysis, Richard C. Zimmerman, Alejandro C. Pasini, Randall S. Alberte

OES Faculty Publications

The importance of submerged aquatic macrophytes to coastal ecosystems has generated a need for knowledge of minimum light levels that will support the maintenance and restoration of healthy populations. Our goals were (1) to evaluate the sensitivity to natural, non-sinusoidal fluctuations in irradiance I of analytical integration techniques for calculating daily carbon gain, (2) to evaluate the H_sat (the daily period of I-saturated photosynthesis) model of daily production relative to models based on instantaneous photosynthesis vs irradiance (P vs I) and (3) to provide some guidance for the temporal density of irradiance data required for accurate estimation of …

The Role Of Sexual Selection In Structuring West Indian Passerine Communities, C. Lynne Starling

College of Graduate Studies: Theses & Dissertations (1964–2006)

Patterns of plumage dimorphism were examined among species of passerines native to 19 West Indian islands. Based on sexual selection theory, the predictions were made that dimorphic species: (1) occur on fewer and larger islands than monomorphic species due to reduced colonization ability and reduced survivorship imposed by sexual selection pressure, and (2) should be added to island communities disproportionately as area increases, an idea which was tested using linear models.

No significant difference was observed between number of islands or minimum island area occupied by dimorphics versus monomorphics. The traditional ANCOVA model best fits the data and suggests that …

Morphology, Fluid Motion And Predation By The Scyphomedusa Aurelia Aurita, John H. Costello, Sean Colin

Arts & Sciences Faculty Publications

Although medusan predators play demonstrably important roles in a variety of marine ecosystems, the mechanics of prey capture and, hence, prey selection, have remained poorly defined. A review of the literature describing the commonly studied medusa Aurelia aurita (Linnaeus 1758) reveals no distinct patterns of prey selectivity and suggests that A. aurita is a generalist and feeds unselectively upon available zooplankton. We examined the mechanics of prey capture by A. aurita using video methods to record body and fluid motions. Medusae were collected between February and June in 1990 and 1991 from Woods Hole, Massachusetts and Narragansett Bay, Rhode Island, …

Susceptibility Of Eumeces Species Skinks To A Southeastern Isolate Of The Lyme Disease Spirochete (Borrelia Burgdorferi), Gregory A. Cummins

College of Graduate Studies: Theses & Dissertations (1964–2006)

The SI-4 strain of Borrelia burgdorferi obtained from field collected Ixodes scapularis on Sapelo Island, Georgia, was infective to seven of eight cotton mice (Peromyscus gossypinus) by needle inoculation. I. scapularis larvae were then fed on them, and nymphs molting from these larvae were then fed on laboratory mice, Mus musculus, in an attempt to transmit the spirochete. One of three mice was successfully infected; confirmation of the presence of B. burgdorferi was made using BSK II culture and the polymerase chain reaction (PGR). A subsequent attempt was made to determine if SI-4 was infective for Eumeces …

Spiroplasma (Entomoplasmatales) Associated With Tabanidae (Diptera) And Lampyridae (Coleoptera), Jimmy Wedincamp Jr.

College of Graduate Studies: Theses & Dissertations (1964–2006)

Abstract 1:

To determine the exit points of Spiroplasma from tabanids, 45 naturally infected Tabanus gladiator and 6 T. sulcifrons were restrained and fed 10% sucrose. The flies were allowed to feed for 24 hours and the resulting oral and anal specks were cultured in MID broth. Spiroplasmas were isolated from 21 of 51 oral specks but none of 23 anal specks deposited on plastic. In contrast, when anal specks were deposited in a sucrose solution, 9 of 28 anal specks in sucrose yielded spiroplasma cultures. Air-dried spiroplasma cultures in 5% sucrose survived for up to 30 days in the …

Characterization And Genetic Analysis Of A Pigmentation Mutant Of Neurospora Crassa, Craig West Banks

College of Graduate Studies: Theses & Dissertations (1964–2006)

The mutant overaccumulator of carotenoids, ovc. was obtained from the Fungal Genetics Stock Center in Kansas City, Kansas. This mutant had been isolated following UV irradiation of the colonial mutant col-4 and mapped to Linkage Group IV (R. Harding, 1984 Neurospora Newsletter 34: 23-25). Examination of ovc in our laboratory revealed that in addition to having increased pigmentation, the mutant was osmotic sensitive, failing to grow on 6% NaCl. Morphology of ovc closely resembles that of cut, another osmotic sensitive mutant in LG IV. A cross of ovc to the osmotic sensitive mutant cut failed to produce …

Using Random Sequence Primers In The Polymerase Chain Reaction To Identify Gender-Specific Genetic Markers In House Wrens, Jeremy J. Kirchman '94

Honors Projects

In order to fully understand the biology of asexually reproducing organism, it is essential that one is able to distinguish the males from the females. In determining the gender of monomorphic birds, standard techniques including visual identification, surgery, and karyotyping are impossible or impractical for large-scale studies. A reliable gender identification method that uses genetic markers identified within the DNA would be an asset to the researcher because it would require only a minimal blood sample which could be collected in the field without harming the bird and stored easily for long periods of time. Griffiths and Tiwari (1993) described …

Toward An Understanding Of Alzheimer's Disease: The Effects Of B-Amyloid(1-42) And Ibotenic Acid On The Retention Of A Spatial Learning Task In Rats F:Ollowing Multiple Injections Into The Hippocampus, Jason Pequette '94

Honors Projects

Neuropathologically, Alzheimer's disease (AD) is characterized by neuritic plaques and neurofibrillary tangles. Evidence has suggested that a protein called B-amyloid (BA) is a major component of the neuritic plaques and may playa role in the neurodegeneration seen in AD. The cellular mechanisms by which BA induces neurotoxicity, however, are still unclear. Recent evidence suggests that the aggregational state of BA may be relevant to its neurotoxicity. Whether portions of the BA protein or the entire sequence produces neurotoxicity in neurons, however, remains a controversy. Still another controversy is whether BA is directly neurotoxic to neurons or whether it increases the …

Rates Of Energy Consumption And Acquisition By Lecithotrophic Larvae Of Bugula Neritina (Bryozoa: Cheilostomata), William Jaeckle

Scholarship

Lecithotrophic larvae of the cheilostome bryozoan, Bugula neritina (L.), lose metamorphic competence 12 to 24 h after release from the maternal zooid. The high respiration rate of newly released larvae (mean=306.3 pmol O₂ larva^-1 h^-1, range= 149.3 to 466.6, n=18 trials, 22.5 °C) from adults collected at Link Port, Fort Pierce, Florida during the winter/spring of 1990-1991 reflects their active swimming behavior. The average energy con¬tent per larva was 15.24 mJ (range: 13.35 to 20.17 mJ ind^-1, n=5 groups). If all cells have an identical energy content and metabolic rate, then 2 and 20% …

Cellular Mechanisms Of Muscle Fatigue, Robert H. Fitts

Biological Sciences Faculty Research and Publications

Fatigue, defined as the failure to maintain the required or expected power output, is a complex problem, since multiple factors are clearly involved, with the relative importance of each dependent on the fiber type composition of the contracting muscles(s), and the intensity, type, and duration of the contractile activity. The primary sites of fatigue appear to be within the muscle cell itself and for the most part do not involve the central nervous system or the neuromuscular junction. The major hypotheses of fatigue center on disturbances in the surface membrane, E-C coupling, or metabolic events. The cell sites most frequently …