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2010

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Articles 31 - 60 of 449

Full-Text Articles in Ecology and Evolutionary Biology

Examination Of Owl Pellets For Northern Pocket Gophers At Crescent Lake National Wildlife Refuge, Nebraska, Stacey L. Bonner, Keith Geluso Dec 2010

Examination Of Owl Pellets For Northern Pocket Gophers At Crescent Lake National Wildlife Refuge, Nebraska, Stacey L. Bonner, Keith Geluso

The Prairie Naturalist

Analysis of regurgitated pellets from owls is a well-known and nondestructive method that provides useful information regarding diet (Errington 1930). This technique also is used to examine composition of small mammal communities and distribution of prey species (e.g. Kamler et al. 2003, Torre et al. 2004, Poole and Matlack 2007). In western Nebraska, two species of owls that regularly breed in the region are the common barn owl (Tyto alba) and great horned owl (Bubo virginianus). In the early 1970s, Rickart (1972) studied the diet of both species at Crescent Lake National Wildlife Refuge (CLNWR), Garden …


Seasonal Yellow Perch Harvest In Two Dissimilar South Dakota Fisheries, Casey W. Schoenebeck, Michael L. Brown, David O. Lucchesi Dec 2010

Seasonal Yellow Perch Harvest In Two Dissimilar South Dakota Fisheries, Casey W. Schoenebeck, Michael L. Brown, David O. Lucchesi

The Prairie Naturalist

Angler effort and fish harvest in South Dakota have historically been quantified through summer and winter creel surveys. However, the late-summer, pulsed recruitment of yellow perch (Perea flavescens) into a fishery combined with an increase in fall movement and feeding activity suggested September and October could be significant periods of perch harvest in South Dakota lakes. Seasonal trends in angler effort and yellow perch harvest during 2005-2007 were compared for high- and low-quality yellow perch fishery types commonly found in eastern South Dakota glacial lakes. High-quality yellow perch fisheries are characterized by fast growth (mean total length at age-3 greater …


Resource Selection Of Greater Prairie-Chicken And Sharp-Tailed Grouse Broods In Central South Dakota, Mark A. Norton, Kent C. Jensen, Anthony P. Leif, Thomas R. Kirschenmann, Gregaory A. Wolbrink Dec 2010

Resource Selection Of Greater Prairie-Chicken And Sharp-Tailed Grouse Broods In Central South Dakota, Mark A. Norton, Kent C. Jensen, Anthony P. Leif, Thomas R. Kirschenmann, Gregaory A. Wolbrink

The Prairie Naturalist

Habitat use of sympatric greater prairie-chicken (Tympanuchus cupido) and sharp-tailed grouse (T. phasianellus) broods during the brood-rearing season has not been quantified for stable prairie grouse populations in large contiguous grassland landscapes in the Northern Great Plains. Characteristics of habitats used by prairie grouse broods were described based on data collected from 35 broods (18 greater prairie-chicken and 17 sharp-tailed grottse) during the breeding seasons of 2004 and 2005. Greater prairie-chicken and sharp-tailed grouse broods used vegetation with visual obstruction heights 2:26 cm and 37 cm, respectively. Greater prairie-chicken broods selected western wheatgrass (Pascopyrum smithii …


Diets Of Nesting Swainson's Hawks In Relation To Land Cover In Northwestern North Dakota, Robert K. Murphy Dec 2010

Diets Of Nesting Swainson's Hawks In Relation To Land Cover In Northwestern North Dakota, Robert K. Murphy

The Prairie Naturalist

Relationships between land use practices and types of prey used by Swainson's hawks (Buteo swainsoni) in the Northern Great Plains is of increasing interest as the quantity and quality of habitat in the region declines. I recorded 1,284 prey items at 18 Swainson' s hawk nesting areas throughout northwestern North Dakota during summer 1986-1987. After correcting for detectability biases and food needs of adults, I estimated (90% CI) 2,087-2,859 total prey individuals and 138.3-206.7 kg of prey biomass (x = 69.8 g/item) were consumed by adult and nestling Swainson's hawks during my study. Major prey (>10% overall …


Pervasive Thermal Consequences Of Stream-Lake Interactions In Small Rocky Mountain Watersheds, Usa, Jessica D. Garrett Dec 2010

Pervasive Thermal Consequences Of Stream-Lake Interactions In Small Rocky Mountain Watersheds, Usa, Jessica D. Garrett

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Limnologists and stream ecologists acknowledge the fundamental importance of temperature for regulating many ecological, biological, chemical, and physical processes. I investigated how water temperatures were affected by hydrologic linkages between streams and lakes at various positions along surface water networks throughout several headwater basins in the Sawtooth and White Cloud Mountains of Idaho (USA). Temperatures of streams and lakes were measured for up to 27 months in seven 6 – 41 km2 watersheds, with a range of lake influence. When they were ice-free, warming in lakes resulted in dramatically warmer temperatures at lake outflows compared to inflow streams (midsummer …


Reconstructing Species Responses To Past Climatic Changes Using Niche Modeling And Genetic Data, Tereza Jezkova Dec 2010

Reconstructing Species Responses To Past Climatic Changes Using Niche Modeling And Genetic Data, Tereza Jezkova

UNLV Theses, Dissertations, Professional Papers, and Capstones

Glacial – interglacial cycles have a pronounced impact on species distributions and genetic structure. Many species shift their distributions to lower latitudes and altitudes during the colder glacial periods and expand northwards and up the elevation during warmer interglacial periods. Some species however are capable of adapting to changing environment which allows them to persist in place despite climatic changes. I explored how climatic changes after the last glacial maximum (LGM) effected two species inhabiting the deserts of western North America: one mammal (Chisel-toothed Kangaroo Rat, Dipodomys microps) and one reptile (Desert Horned Lizard, Phrynosoma platyrhinos). I used …


Effect Of Spatial And Temporal Variability Of Antecedent Moisture Content On Model-Generated Runoff From An Arid Watershed, William J. Meyer Dec 2010

Effect Of Spatial And Temporal Variability Of Antecedent Moisture Content On Model-Generated Runoff From An Arid Watershed, William J. Meyer

UNLV Theses, Dissertations, Professional Papers, and Capstones

Streams in the arid southwest are typically ephemeral, and stream gages are not commonly available. Consequently, runoff data from storm events is not available, and flood control facility design or other water resource related decisions are based on synthetic hydrographs. In the Mojave Desert region of Southern Nevada, the duration of storm used to develop these synthetic hydrographs is the 6 hour storm. The 6 hour storm is used to simulate high intensity summer storms. Additionally, soils information used in the calculations for these synthetic hydrographs is taken from maps that are generally developed for a broad range of issues …


Distributions Of Sharks Across A Continental Shelf In The Northern Gulf Of Mexico, J. Marcus Drymon, Sean P. Powers, John Dindo, Brian Dzwonkowski, Terry A. Henwood Dec 2010

Distributions Of Sharks Across A Continental Shelf In The Northern Gulf Of Mexico, J. Marcus Drymon, Sean P. Powers, John Dindo, Brian Dzwonkowski, Terry A. Henwood

University Faculty and Staff Publications

Declines in shark populations have sparked researchers and fishery managers to investigate more prudent approaches to the conservation of these fish. As managers strive to improve data collection for stock assessment, fisheries-independent surveys have expanded to include data-deficient areas such as coastal regions. To that end, a catch series from a nearshore survey off Alabama was combined with data from a concurrent offshore survey with identical methodology to examine the depth use of sharks across the continental shelf (2–366 m). The combined data set contained 22 species of sharks collected from 1995 to 2008: 21 species in the offshore data …


Population And Diet Assessment Of White Bass In Lake Sharpe, South Dakota, Andrew E. Ahrens, Travis W. Schaeffer, Melissa R. Wuellner, David W. Willis Dec 2010

Population And Diet Assessment Of White Bass In Lake Sharpe, South Dakota, Andrew E. Ahrens, Travis W. Schaeffer, Melissa R. Wuellner, David W. Willis

The Prairie Naturalist

White bass (Morone chrysops) have been introduced into all 4 South Dakota Missouri River reservoirs and compose a substantial proportion of the annual recreational harvest. To date, limited studies have examined white bass population dynamics and food habits in South Dakota Missouri River reservoirs. Our objective was to examine population dynamics and food habits of white bass in Lake Sharpe, a South Dakota mainstem Missouri River reservoir. White bass consistently consumed invertebrates during May but switched to a more piscivorous diet later in the growing season; most of the fish consumed were gizzard shad (Dorosoma cepedianum). …


Correlation Of Mature Walleye Relative Abundance To Egg Density, Jordan D. Katt, Casey W. Schoenebeck, Keith D. Koupal, Brian C. Peterson, W. Wyatt Hoback Dec 2010

Correlation Of Mature Walleye Relative Abundance To Egg Density, Jordan D. Katt, Casey W. Schoenebeck, Keith D. Koupal, Brian C. Peterson, W. Wyatt Hoback

The Prairie Naturalist

Knowledge of spawning areas can benefit fisheries management (Marsden et al. 1991). Identification of spawning areas allows managers to protect, enhance, and/or restore critical habitat (Gunn et al. 1996, Thompson 2009), examine important biotic and abiotic conditions necessary for reproduction (Quist et al. 2003), and to efficiently collect broodstock for production (Satterfield and Flickinger 1996). The most effective method to directly identify spawning areas of fish with demersal eggs is to sample the substrate for eggs (Marsden et al. 1991). This method has been used to locate spawning areas of several species (Michaletz 1984, Zorn et al. 1998, Martin 2008). …


The Prairie Naturalist, Vol. 42, Issue 3/4, December 2010, The Great Plains Natural Science Society Dec 2010

The Prairie Naturalist, Vol. 42, Issue 3/4, December 2010, The Great Plains Natural Science Society

The Prairie Naturalist

EDITOR'S NOTE: REPORTING RESULTS OF DATA ANALYSIS, PREPARING SCIENTIFIC MANUSCRIPTS, AND WEBSITE DEVELOPMENT EFFORTS • Christopher N. Jacques

Current Distribution of Rare Fishes in Eastern Wyoming Prairie Streams • Christina E. Barrineau, Elizabeth A. Bear, and Anna C. Senecal

Diets of Nesting Swainson's Hawks in Relation to Land Cover in Northwestern North Dakota • Robert K. Murphy

Resource Selection of Greater Prairie-Chicken and and Sharp-Tailed Grouse Broods in Central South Dakota • Mark A. Norton, Kent C. Jensen, Anthony P. Leif, Thomas R. Kirschenmann, and Gregory A. Wolbrink

Population Characteristics of Central Stonerollers in Iowa Streams • Scott M Bisping, …


Population Characteristics Of Central Stonerollers In Iowa Streams, Scott M. Bisping, Jesse R. Fischer, Michael C. Quist, Andrew J. Schaefer Dec 2010

Population Characteristics Of Central Stonerollers In Iowa Streams, Scott M. Bisping, Jesse R. Fischer, Michael C. Quist, Andrew J. Schaefer

The Prairie Naturalist

The central stoneroller (Campostoma anomalum) is a herbivore that can have substantial effects on algal communities, nutrient dynamics, and energy flow in streams. Despite its importance in lotic ecosystems, little is known about its population dynamics in streams of the Great Plains. Our objective was to describe age structure, age-specific mortality, and growth rates of central stonerollers in three Iowa streams. We sampled fish from 41 reaches during June-August 2007. We sampled 466 central stonerollers, of which we aged 192. Fish varied in length from 32 to 130 mm and in age from age 0 to 4 years. …


How Are The Torres Strait Islander's Traditional Hunting Practices Affected By The Current Rate Of Decline In Dugong And Sea Turtle Populations And The Australian Government's Co-Management Policies On Marine Preservation?, Katilyn Price Dec 2010

How Are The Torres Strait Islander's Traditional Hunting Practices Affected By The Current Rate Of Decline In Dugong And Sea Turtle Populations And The Australian Government's Co-Management Policies On Marine Preservation?, Katilyn Price

Department of Environmental Studies: Undergraduate Student Theses

This paper will attempt to identify the extent to which the Torres Strait Islanders traditional hunting practices have been disrupted by the overall decline in dugong and sea turtle populations, which has directly correlated to an increase in hunting restrictions put in place by the Australian Government. The traditional hunting of dugongs and sea turtles provides not only a food source, but brings prestige to the men who catch them and serves as an educational platform to teach the younger generations about their culture. There are many environmental threats that impact the populations of sea turtles and dugongs though the …


Hydraulic Conductivity, Infiltration, And Runoff From No-Till And Tilled Cropland, Jessica H. Deck Dec 2010

Hydraulic Conductivity, Infiltration, And Runoff From No-Till And Tilled Cropland, Jessica H. Deck

Department of Environmental Engineering: Theses and Other Student Research

Infiltration and runoff are important processes that affect the efficiency of center pivot irrigation systems. No-till planting systems potentially influence the hydraulic properties of soils and the soil surface conditions. The result of long-term use of no-till could be higher infiltration and lower runoff from rainfall and irrigation.

This potential was investigated in Nebraska on two center pivot irrigated sites; Fillmore County and Phelps County, one furrow irrigated site; South Central Agriculture Laboratory (SCAL), and one dryland site; Rogers Farm. Paired treatments were used at each location, one that was no-till planted and one that used two to three operations …


Phenotypic And Genetic Characterization Of Wildland Collections Of Western And Searls Prairie Clovers For Rangeland Revegetation In The Western Usa, Kishor Bhattarai Dec 2010

Phenotypic And Genetic Characterization Of Wildland Collections Of Western And Searls Prairie Clovers For Rangeland Revegetation In The Western Usa, Kishor Bhattarai

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Western prairie clover [Dalea ornata (Douglas ex Hook.) Eaton & J. Wright] is a perennial legume that occurs in the northern Great Basin, Snake River Basin, and southern Columbia Plateau, whereas Searls prairie clover [Dalea searlsiae (A. Gray) Barneby], also a perennial legume, occurs in the southern Great Basin and surrounding areas. Understanding the genetic and ecotypic variation of these prairie clovers is a prerequisite for developing populations suitable for rangeland revegetation in the western USA. DNA sequences of internal transcribed spacer (ITS/5.8S) and trnK/matK were used to study the phylogeny of these species. The species were distinguished …


Twenty-Eight Years Of The Us-Lter Program: Experience, Results, And Research Questions, James R. Gosz, Robert B. Waide, John J. Magnuson Dec 2010

Twenty-Eight Years Of The Us-Lter Program: Experience, Results, And Research Questions, James R. Gosz, Robert B. Waide, John J. Magnuson

Long Term Ecological Research Network

The U.S. Long Term Ecological Research program (hereafter US-LTER) concentrates on ecological processes that play out at the time scales spanning decades to centuries. This focuses US-LTER research between the most common time scales for ecological studies (1-3 years; Tilman 1989; Figure 1) and the much longer temporal fact of disciplines such as paleoecology. The importance of the decade-to-century time scale is particularly evident in light of the rapid changes in ecological forcing functions that are occurring at a broad range of spatial scales (Millennium Ecosystem Assessment 2005, Intergovernmental Panel on Climate Change 2007). Long-term data sets from programs such …


Coaching Efficacy With Academic Leaders: A Phenomenological Investigation, Deanna Lee Vansickel-Peterson Nov 2010

Coaching Efficacy With Academic Leaders: A Phenomenological Investigation, Deanna Lee Vansickel-Peterson

College of Education and Human Sciences: Dissertations, Theses, and Student Research

The purpose of this psychological phenomenological research was to understand the efficacy of life coaching from the perspective of academic leaders. To date, not one investigation or attempt has been made towards the above stated purpose. This study includes a theoretical overview and a review of the coaching literature from Socrates (469-399 BC) to current day Humanistic theory presented in part by Roger (1902-1987). This process included data collection from five academic leaders who have been coached for at least two years. Levels of analysis of 365 statements, quote and/or comments produced finding of efficacy in life coaching with academic …


A New Species Of Pristimantis (Anura: Strabomantidae) From The Amazonian Lowlands Of Northern Peru, Edgar Lehr, Luis Gagliardi Urrutia Nov 2010

A New Species Of Pristimantis (Anura: Strabomantidae) From The Amazonian Lowlands Of Northern Peru, Edgar Lehr, Luis Gagliardi Urrutia

Scholarship

We describe a new species of Pristimantis from the vicinity of Puerto Almendras, ca. 17 km straight southwest of Iquitos, Provincia Maynas, Region Loreto, Peru. With seven other species (P. carvalhoi, P. croceoinguinis, P. divnae, P. lirellus, P. minutulus, P. toftae, P. variabilis) from the Amazonian lowlands and lower eastern Andes in Peru, the new species shares a yellow groin and broadly expanded discs on fingers and toes. However, the new species can be distinguished by the follow¬ing combination of characters: snout–vent length 14.8 mm in the single male, 20.0–22.0 mm in females, strongly tubercular dorsal skin, absence of dorsolateral …


Moving Towards A Complete Molecular Framework Of The Nematoda: A Focus On The Enoplida And Early-Branching Clades, Holly M. Bik, P. John D. Lambshead, W. Kelley Thomas, David H. Lunt Nov 2010

Moving Towards A Complete Molecular Framework Of The Nematoda: A Focus On The Enoplida And Early-Branching Clades, Holly M. Bik, P. John D. Lambshead, W. Kelley Thomas, David H. Lunt

Hubbard Center for Genome Studies (HCGS)

Background: The subclass Enoplia (Phylum Nematoda) is purported to be the earliest branching clade amongst all nematode taxa, yet the deep phylogeny of this important lineage remains elusive. Free-living marine species within the order Enoplida play prominent roles in marine ecosystems, but previous Molecular phylogenies have provided only the briefest evolutionary insights; this study aimed to firmly resolve internal relationships within the hyper diverse but poorly understood Enoplida. In addition, we revisited the Molecular framework of the Nematoda using a rigorous phylogenetic approach in order to investigate patterns of early splits amongst the oldest lineages (Dorylaimia and Enoplia). Results: Morphological …


Sound Diversity In The Landscape: The Effects Of Land Use, Luis J. Villanueva-Rivera, Bryan C. Pijanowski Nov 2010

Sound Diversity In The Landscape: The Effects Of Land Use, Luis J. Villanueva-Rivera, Bryan C. Pijanowski

GIS Day

Climate change, land use change and the introduction of exotic species are the three most important anthropogenic threats to the ecosystems and their biodiversity. In order to evaluate the impacts these threats are having, ecologists need better methods to measure, in space and time, the biodiversity in a fast and scalable way. Our group is proposing the use of the sounds produced by animals in a landscape, the biophony, as a proxy for the biodiversity. As a first step in the quantification of biophony, we collected sound recordings from seven sites in the Tippecanoe County, Indiana. These sites were located …


Micrornas Reveal The Interrelationships Of Hagfish, Lampreys, And Gnathostomes And The Nature Of The Ancestral Vertebrate, Alysha M. Heimberg, Richard Cowper-Sal{Middle Dot}Lari, Marie Semon, Philip C. J. Donoghue, Kevin J. Peterson Nov 2010

Micrornas Reveal The Interrelationships Of Hagfish, Lampreys, And Gnathostomes And The Nature Of The Ancestral Vertebrate, Alysha M. Heimberg, Richard Cowper-Sal{Middle Dot}Lari, Marie Semon, Philip C. J. Donoghue, Kevin J. Peterson

Dartmouth Scholarship

Hagfish and lampreys are the only living representatives of the jawless vertebrates (agnathans), and compared with jawed vertebrates (gnathostomes), they provide insight into the embryology, genomics, and body plan of the ancestral vertebrate. However, this insight has been obscured by controversy over their interrelationships. Morphological cladistic analyses have identified lampreys and gnathostomes as closest relatives, whereas molecular phylogenetic studies recover a monophyletic Cyclostomata (hagfish and lampreys as closest relatives). Here, we show through deep sequencing of small RNA libraries, coupled with genomic surveys, that Cyclostomata is monophyletic: hagfish and lampreys share 4 unique microRNA families, 15 unique paralogues of more …


Match–Mismatch Regulation For Bluegill And Yellow Perch Larvae And Their Prey In Sandhill Lakes, Jeffrey C. Jolley, David W. Willis, Richard S. Holland Nov 2010

Match–Mismatch Regulation For Bluegill And Yellow Perch Larvae And Their Prey In Sandhill Lakes, Jeffrey C. Jolley, David W. Willis, Richard S. Holland

Nebraska Game and Parks Commission: Staff Research Publications

Food availability may regulate fish recruitment, both directly and indirectly. The availability of zooplankton, especially to newly hatched larvae, is thought to be crucial to their early growth and survival. We examined stomach contents of larval bluegill Lepomis macrochirus and yellow perch Perca flavescens in Pelican Lake and Cameron Lake, Nebraska, in 2004 and 2005. We also determined zooplankton availability and calculated prey selection using Chesson’s a. In addition, we investigated potential match–mismatch regulation of recruitment from 2004 to 2008. Bluegill positively selected copepod nauplii and Bosmina spp., and yellow perch often selected copepods. Abundant zooplankton populations were available for …


Current Status And Long-Term Trends In Water Quality And Living Resources In The Virginia Tributaries And Chesapeake Bay Mainstem From 1985 Through 2009, Daniel M. Dauer, Harold G. Marshall, John R. Donat, Michael F. Lane, Suzanne C. Doughten, Frederick A. Hoffman, Raghavendra Kurada Nov 2010

Current Status And Long-Term Trends In Water Quality And Living Resources In The Virginia Tributaries And Chesapeake Bay Mainstem From 1985 Through 2009, Daniel M. Dauer, Harold G. Marshall, John R. Donat, Michael F. Lane, Suzanne C. Doughten, Frederick A. Hoffman, Raghavendra Kurada

Status and Trends for Virginia Chesapeake Bay

The period prior to the implementation of the Chesapeake Bay Monitoring Program was characterized by a marked decline in the water quality of the Chesapeake Bay. The disappearance of submerged aquatic vegetation in certain regions of the Bay, declines in the abundance of some commercially and recreationally important species, increases in the incidence of low dissolved oxygen events, changes in the Bay's food web, and other ecological problems have been related to the deteriorating water quality (e.g. USEPA, 1982,1983;Officer et al.,1984; Orth and Moore, 1984). The results of concentrated research efforts in the late 1970s and early 1980s stimulated the …


On The Evidence For Species Coexistence: A Critique Of The Coexistence Program, Adam M. Siepielski, Mark A. Mcpeek Nov 2010

On The Evidence For Species Coexistence: A Critique Of The Coexistence Program, Adam M. Siepielski, Mark A. Mcpeek

Dartmouth Scholarship

A major challenge in ecology is to understand how the millions of species on Earth are organized into biological communities. Mechanisms promoting coexistence are one such class of organizing processes, which allow multiple species to persist in the same trophic level of a given web of species interactions. If some mechanism promotes the coexistence of two or more species, each species must be able to increase when it is rare and the others are at their typical abundances; this invasibility criterion is fundamental evidence for species coexistence regardless of the mechanism. In an attempt to evaluate the level of empirical …


Accelerated Erosion Of Saltmarshes Infested By The Non-Native Burrowing Crustacean Sphaeroma Quoianum, Timothy Mathias Davidson, Catherine E. De Rivera Nov 2010

Accelerated Erosion Of Saltmarshes Infested By The Non-Native Burrowing Crustacean Sphaeroma Quoianum, Timothy Mathias Davidson, Catherine E. De Rivera

Environmental Science and Management Faculty Publications and Presentations

Lateral erosion of saltmarshes is affected by many abiotic and biotic factors. While abiotic factors are typically regarded as primary drivers of erosion, biotic influences such as burrowing or bioturbating taxa can also extensively modify the physical structure of this marine habitat. Many estuaries on the Pacific coast of North America have been invaded by populations of the burrowing non-native isopod Sphaeroma quoianum, which are thought to exacerbate the erosion of saltmarshes. We conducted a mensurative experiment to examine the relationship between populations of S. quoianum and lateral erosion rate of saltmarshes in Coos Bay, Oregon, USA. After 1 …


Ecological Effects Of Virus-Resistant Transgenic Squash, Holly R. Prendeville Nov 2010

Ecological Effects Of Virus-Resistant Transgenic Squash, Holly R. Prendeville

School of Biological Sciences: Dissertations, Theses, and Student Research

Two ecological risks associated with the use of transgenic crops include the effects of transgene products on non-target organisms and the effects of a transgene after it moves from crops into a wild plant population. In work presented here, we specifically investigate the ecological risks of virus-resistant transgenic squash. We observed pollinator behavior to determine if pollinators are affected by nontarget effects of the virus-resistant transgene. We found that pollinator behavior did differ between conventional and virus-resistant transgenic squash due to pleiotropic effects of the transgene. This difference in pollinator behavior can affect plant mating patterns, thereby affecting crop-wild hybridization …


Time, Temperature And Species Interactions In A Duckweed–Herbivore Mesocosm, Ian Waterman Nov 2010

Time, Temperature And Species Interactions In A Duckweed–Herbivore Mesocosm, Ian Waterman

School of Biological Sciences: Dissertations, Theses, and Student Research

Species interactions within a community are impacted by a variety of abiotic factors. Temperature is known to alter population dynamics such that direct and indirect interactions between populations within a community are affected. Here I investigate the effect of temperature change on species interactions within a duckweed-herbivore mesocosm. Multiple communities were constructed, from a single population of duckweed, to two populations of duckweed consumed by aphids. In the one-predator two-prey web we predicted mutually positive indirect effects between duckweed populations during the first generation of growth. As aphid populations respond numerically to more abundant prey, mutually negative and asymmetric indirect …


Evolutionary Rates And Gene Dispensability Associate With Replication Timing In The Archaeon Sulfolobus Islandicus, Kenneth M. Flynn, Samuel H. Vohr, Philip J. Hatcher, Vaughn S. Cooper Oct 2010

Evolutionary Rates And Gene Dispensability Associate With Replication Timing In The Archaeon Sulfolobus Islandicus, Kenneth M. Flynn, Samuel H. Vohr, Philip J. Hatcher, Vaughn S. Cooper

Molecular, Cellular & Biomedical Sciences

In bacterial chromosomes, the position of a gene relative to the single origin of replication generally reflects its replication timing, how often it is expressed, and consequently, its rate of evolution. However, because some archaeal genomes contain multiple origins of replication, bias in gene dosage caused by delayed replication should be minimized and hence the substitution rate of genes should associate less with chromosome position. To test this hypothesis, six archaeal genomes from the genus Sulfolobus containing three origins of replication were selected, conserved orthologs were identified, and the evolutionary rates (dN and dS) of these orthologs were quantified. Ortholog …


Cortical Representation Of Lateralized Grasping In Chimpanzees (Pan Troglodytes): A Combined Mri And Pet Study, William D. Hopkins, Jared P. Taglialatela, Jamie L. Russell, Talia M. Nir, Jennifer Schaeffer Oct 2010

Cortical Representation Of Lateralized Grasping In Chimpanzees (Pan Troglodytes): A Combined Mri And Pet Study, William D. Hopkins, Jared P. Taglialatela, Jamie L. Russell, Talia M. Nir, Jennifer Schaeffer

Faculty Articles

Functional imaging studies in humans have localized the motor-hand region to a neuroanatomical landmark call the KNOB within the precentral gyrus. It has also been reported that the KNOB is larger in the hemisphere contralateral to an individual's preferred hand, and therefore may represent the neural substrate for handedness. The KNOB has also been neuronatomically described in chimpanzees and other great apes and is similarly associated with handedness. However, whether the chimpanzee KNOB represents the hand region is unclear from the extant literature. Here, we used PET to quantify neural metabolic activity in chimpanzees when engaged in unilateral reach-and-grasping responses …


Osteology, Natural History Notes, And Phylogenetic Relationships Of The Poorly Known Caribbean Frog Leptodactylus Nesiotus (Anura, Leptodactylidae), María Laura Ponssa, Michael J. Jowers, Rafael O. De Sá Oct 2010

Osteology, Natural History Notes, And Phylogenetic Relationships Of The Poorly Known Caribbean Frog Leptodactylus Nesiotus (Anura, Leptodactylidae), María Laura Ponssa, Michael J. Jowers, Rafael O. De Sá

Biology Faculty Publications

The Leptodactylus melanonotus group consists of 15 species, but references to skeletal characters are available for only three species: L. leptodactyloides, L. melanonotus, and L. diedrus. Leptodactylus nesiotus is a member of the melanonotus group known only from the type locality, Bonasse swamp, on the Southwestern peninsula of Trinidad, Trinidad and Tobago. This species has been categorized as vulnerable given its restricted distribution. Herein, we report the adult osteology of L. nesiotus, the skeletal characters are compared with the available data from other Leptodactylus species. A phylogenetic analysis recovers a paraphyletic L. melanonotus group relative to the L. …