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Articles 991 - 1020 of 1028

Full-Text Articles in Evolution

Determining The Composition Of The Dwelling Tubes Of Antarctic Pterobranchs, Lukasz J. Sewera Apr 2011

Determining The Composition Of The Dwelling Tubes Of Antarctic Pterobranchs, Lukasz J. Sewera

Honors Projects

Pterobranchs are a group of marine invertebrates within the Hemichordata, which share characteristics with both chordates and echinoderms.  Pterobranchs live in colonies of secreted tubes, coenicia, which are composed of a gelatinous material of unknown composition.  Visually, the tubes appear similar to the tunic of tunicates, a group of invertebrates within the Chordata. The nonproteinaceous tunic of tunicates is composed of cellulose, which is unusual.  The goal of this study was to determine the composition of the pterobranch coenicium. Some aspects of pterobranch phylogeny are still unclear even after multiple molecular and morphological studies.  Identification of any new shared characteristics …


The Genus Butheoloides Hirst, 1925 (Scorpiones, Buthidae) In Morocco, With A Description Of А New Species, Wilson R. Lourenço, Oulaid Touloun, Ali Ali Boumezzough Apr 2011

The Genus Butheoloides Hirst, 1925 (Scorpiones, Buthidae) In Morocco, With A Description Of А New Species, Wilson R. Lourenço, Oulaid Touloun, Ali Ali Boumezzough

Euscorpius

A new species belonging to the genus Butheoloides Hirst, 1925 (subgenus Butheoloides Hirst, 1925) (Scorpiones, Buthidae) is described from two localities in Morocco: north of Sidi Ifni in the southern coast and Sidi Moussa west of Tiznit. With the description of Butheoloides (Butheoloides) littoralis sp. n., the total number of species of this genus known from Morocco is raised to five. This makes Morocco the region in Africa with the highest diversity for Butheoloides species.


Multilocus And Parametric Analyses Of The Evolutionary History Of The Amazonian Peacock Cichlids, The Genus Cichla (Teleostei: Cichlidae), Stuart Clayton Willis Apr 2011

Multilocus And Parametric Analyses Of The Evolutionary History Of The Amazonian Peacock Cichlids, The Genus Cichla (Teleostei: Cichlidae), Stuart Clayton Willis

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

Accurate knowledge of species boundaries and species phylogeny are fundamental to testing hypotheses of recent evolutionary processes, but the estimation of these partitions is challenging due both to inherent confusion about what is being estimated as well as the data available to estimate them. Using multilocus data from mtDNA, microsatellites, and nuclear locus sequences of over 1100 individuals, we delimited eight separately evolving species of Cichla rather than the 15 described. Among species we found evidence of rare but widespread introgressive hybridization, while within these species we observed evidence of long-term gene exchange and constrained evolutionary trajectories. In most cases …


Contributions To Scorpion Systematics. Iv. Observations On The Hadrurus “Spadix” Subgroup With A Description Of A New Species (Scorpiones: Caraboctonidae), Michael E. Soleglad, Victor Fet, Graeme Lowe Feb 2011

Contributions To Scorpion Systematics. Iv. Observations On The Hadrurus “Spadix” Subgroup With A Description Of A New Species (Scorpiones: Caraboctonidae), Michael E. Soleglad, Victor Fet, Graeme Lowe

Euscorpius

In this study new data are presented on the “spadix” subgroup of genus Hadrurus, including the description of a new species, H. anzaborrego, sp. nov., found primarily in the Anza-Borrego Desert State Park (ABDSP) in southern California, USA. This species is distinguished by its internal trichobothrial pattern of the chela and its unique carapace pattern. The status of Hadrurus obscurus Williams, 1970 is discussed and new locality data for this species are provided. A phylogenetic key to the genera, species, and subspecies of subfamily Hadrurinae is provided.


Serradigitus Miscionei (Scorpiones: Vaejovidae), A New Species From Southern Arizona, Richard F. Ayrey Feb 2011

Serradigitus Miscionei (Scorpiones: Vaejovidae), A New Species From Southern Arizona, Richard F. Ayrey

Euscorpius

A new scorpion species, Serradigitus miscionei, is described, placed in the genus Serradigitus Stahnke, 1974. These are small reddish-brown scorpions found on vertical surfaces, in the San Pedro River system and other river systems in southern, Arizona.


The Genus Chaerilus Simon, 1877 (Scorpiones, Chaerilidae) In The Indian Ocean Islands And Description Of A New Species, Wilson R. Lourenço, Bernard Duhem, Elise-Anne Leguin Jan 2011

The Genus Chaerilus Simon, 1877 (Scorpiones, Chaerilidae) In The Indian Ocean Islands And Description Of A New Species, Wilson R. Lourenço, Bernard Duhem, Elise-Anne Leguin

Euscorpius

A new species is described belonging to the genus Chaerilus Simon, 1877. Chaerilus andamanensis sp. n. was discovered in the Island of Little Andaman in the Indian Ocean. The new species shows affinities with Chaerilus variegatus Simon, 1877 and Chaerilus borneensis Simon, 1880, respectively described from Java and Borneo. This s the first record of the genus Chaerilus in the Andaman Islands.


On Two Subspecies Of Mesobuthus Eupeus (C. L. Koch, 1839) In Turkey (Scorpiones: Buthidae), František Kovařík, Ersen Aydın Yağmur, Victor Fet, Shahrokh Navidpour Jan 2011

On Two Subspecies Of Mesobuthus Eupeus (C. L. Koch, 1839) In Turkey (Scorpiones: Buthidae), František Kovařík, Ersen Aydın Yağmur, Victor Fet, Shahrokh Navidpour

Euscorpius

Examination of 268 specimens of Mesobuthus eupeus eupeus (C. L. Koch, 1839) and 1765 specimens of M. eupeus phillipsii (Pocock, 1889) from 163 localities, 92 of them in Turkey, has enabled us to establish distribution of the two subspecies and limits of their ranges in southeastern Turkey. A map of distribution of these subspecies in Turkey and a key to Turkish Mesobuthus species and subspecies are provided. Buthus eupeus philippovitschi Birula, 1905 is synonymized with Mesobuthus eupeus eupeus, and Buthus eupaeus mesopotamicus Penther, 1912 is synonymized with Mesobuthus eupeus phillipsii.


A New Species Of Orthochirus Karsch, 1892 (Scorpiones: Buthidae) From Maharashtra, India, Amod M. Zambre, Zeeshan A. Mirza, Rajesh V. Sanap, Raman Upadhye, S. M. Maqsood Javed Jan 2011

A New Species Of Orthochirus Karsch, 1892 (Scorpiones: Buthidae) From Maharashtra, India, Amod M. Zambre, Zeeshan A. Mirza, Rajesh V. Sanap, Raman Upadhye, S. M. Maqsood Javed

Euscorpius

A new species of scorpions of the genus Orthochirus (Buthidae) is described from Jalna, Maharashtra, India. A key to Indian scorpion of the genus Orthochirus is provided.


Compsobuthus Sindicus Sp. N. From Pakistan (Scorpiones: Buthidae), František Kovařík, Zubair Ahmed Jan 2011

Compsobuthus Sindicus Sp. N. From Pakistan (Scorpiones: Buthidae), František Kovařík, Zubair Ahmed

Euscorpius

Compsobuthus sindicus sp. n. of the werneri group is described from Pakistan, Sind Province, near the border with India. It is characterized chiefly by densely granulated carapace mesosoma, metasoma, telson, and femur and patella of pedipalps; the first to fourth metasomal segments bear 10 carinae. C. sindicus sp. n. is closest to C. rugosulus (Pocock, 1900) from India and Pakistan, from which it differs chiefly in having the first metasomal segment approximately as wide as long.


Mechanisms For Decisions About The Future, Jeffrey R. Stevens Jan 2011

Mechanisms For Decisions About The Future, Jeffrey R. Stevens

Jeffrey Stevens Publications

Evolutionary and psychological perspectives on decision making remain largely separate endeavors. The bounded rationality approach integrates these two perspectives by focusing on simple, plausible mechanisms of decision making and the cognitive capacities needed to implement these mechanisms. Decisions about the future provide a class of decisions that lend themselves to a bounded rationality approach. Though many different mechanisms may exist for making decisions about the future, only a subset of these mechanisms actually require a representation of the future. The bounded rationality approach helps focus on the cognitive capacities and decision mechanisms that are necessary for a full understanding of …


Phylogeography Of Northern Populations Of The Black-Tailed Rattlesnake (Crotalus Molossus Baird And Girard, 1853) With The Revalidation Of C. Ornatus Hallowell, 1854, Christopher Anderson Jan 2011

Phylogeography Of Northern Populations Of The Black-Tailed Rattlesnake (Crotalus Molossus Baird And Girard, 1853) With The Revalidation Of C. Ornatus Hallowell, 1854, Christopher Anderson

Open Access Theses & Dissertations

The black-tailed rattlesnake (Crotalus molossus Baird and Girard, 1853) is a wide-ranging species complex with representatives from the southwestern United States through the highlands of central and southern Mexico. The systematics of this group has received little attention and in the past six decades only two taxonomic revisions have been proposed (the transfer of C. basiliscus oaxacus to C. molossus and the elevation of C. m. estebanensis to full species). However, a recent revision of the Neotropical rattlesnakes (C. durissus and C. simus) recovered a polyphyletic C. molossus. Sequenced data were obtained from three mitochondrial genes …


Communication For Mate Selection In Anurans: Dominant Frequency Versus Snout-Vent-Length, Shari Jean Kunert Dec 2010

Communication For Mate Selection In Anurans: Dominant Frequency Versus Snout-Vent-Length, Shari Jean Kunert

Department of Environmental Studies: Undergraduate Student Theses

No abstract provided.


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 …


Ecology And Relationships Of Rhabdias Spp. (Nematoda: Rhabdiasidae) From North American Amphibians And Reptiles, Gabriel J. Langford May 2010

Ecology And Relationships Of Rhabdias Spp. (Nematoda: Rhabdiasidae) From North American Amphibians And Reptiles, Gabriel J. Langford

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

Lungworms of the cosmopolitan genus Rhabdias (Nematoda: Rhabdiasidae) are among the most common parasites of amphibians and squamate reptiles. The life cycles, life histories, host specificities, and evolutionary relationships of Rhabdias spp. were studied through examination of their free-living and parasitic stages in amphibians and reptiles. This study found free-living development of anuran lungworms was primarily limited to heterogonic reproduction, whereas snake lungworms primarily reproduced homogonically. Infective anuran lungworms penetrated the skin of frogs and toads; in contrast, snake lungworms penetrated snake esophageal tissue during per os infections. Our molecular phylogeny strongly supported separate clades for anuran and snake lungworms, …


It's Not Too Late For The Harpy Eagle (Harpia Harpyja): High Levels Of Genetic Diversity And Differentiation Can Fuel Conservation Programs, Heather R. Lerner, Jeff A. Johnson, Alec R. Lindsay Ph. D., Lloyd F. Kiff, David P. Mindell Oct 2009

It's Not Too Late For The Harpy Eagle (Harpia Harpyja): High Levels Of Genetic Diversity And Differentiation Can Fuel Conservation Programs, Heather R. Lerner, Jeff A. Johnson, Alec R. Lindsay Ph. D., Lloyd F. Kiff, David P. Mindell

Faculty Works

Background: The harpy eagle (Harpia harpyja) is the largest Neotropical bird of prey and is threatened by human persecution and habitat loss and fragmentation. Current conservation strategies include local education, captive rearing and reintroduction, and protection or creation of trans-national habitat blocks and corridors. Baseline genetic data prior to reintroduction of captive-bred stock is essential for guiding such efforts but has not been gathered previously.

Methodology/Findings: We assessed levels of genetic diversity, population structure and demographic history for harpy eagles using samples collected throughout a large portion of their geographic distribution in Central America (n = 32) and South America …


A Study Of The Morphology Of Tatenectes Laramiensis, A Cryptocleidoid Plesiosaur From The Sundance Formation (Wyoming, Usa), Hallie P. Street Jan 2009

A Study Of The Morphology Of Tatenectes Laramiensis, A Cryptocleidoid Plesiosaur From The Sundance Formation (Wyoming, Usa), Hallie P. Street

Theses, Dissertations and Capstones

Tatenectes laramiensis is a cryptocleidoid plesiosaur from the Late Jurassic Sundance Formation. This study primarily concerns a partial skeleton comprised of dorsal vertebrae, ribs, gastralia, and pelvic girdle. Even though the skeleton is incomplete, it is hypothesized that the preserved fossils are sufficient to indicate the overall body shape and also the preferred habitat of Tatenectes. Possibly the most notable of the novel characters is the pachyostotic state of the gastralia. In relation to the ribs and overall size of Tatenectes, in comparison to the gastralia in related taxa, these gastralia are disproportionately robust. The combination of these morphologies suggests …


On The Monkeys Of The Amazon (1852), Alfred Russel Wallace Jan 2009

On The Monkeys Of The Amazon (1852), Alfred Russel Wallace

Alfred Russel Wallace Classic Writings

No abstract provided.


On The Law Which Has Regulated The Introduction Of New Species (1855), Alfred Russel Wallace Jan 2009

On The Law Which Has Regulated The Introduction Of New Species (1855), Alfred Russel Wallace

Alfred Russel Wallace Classic Writings

No abstract provided.


On The Tendency Of Varieties To Depart Indefinitely From The Original Type (1858), Alfred Russel Wallace Jan 2009

On The Tendency Of Varieties To Depart Indefinitely From The Original Type (1858), Alfred Russel Wallace

Alfred Russel Wallace Classic Writings

No abstract provided.


Primate Phylogenomics: Developing Numerous Nuclear Non-Coding, Non-Repetitive Markers For Ecological And Phylogenetic Applications And Analysis Of Evolutionary Rate Variation, Zuogang Peng, Navin Elango, Derek E. Wildman, Soojin V. Yi Jan 2009

Primate Phylogenomics: Developing Numerous Nuclear Non-Coding, Non-Repetitive Markers For Ecological And Phylogenetic Applications And Analysis Of Evolutionary Rate Variation, Zuogang Peng, Navin Elango, Derek E. Wildman, Soojin V. Yi

Wayne State University Associated BioMed Central Scholarship

Abstract

Background

Genetic analyses are often limited by the availability of appropriate molecular markers. Markers from neutrally evolving genomic regions may be particularly useful for inferring evolutionary histories because they escape the constraints of natural selection. For the majority of taxa however, obtaining such markers is challenging. Advances in genomics have the potential to alleviate the shortage of neutral markers. Here we present a method to develop numerous markers from putatively neutral regions of primate genomes.

Results

We began with the available whole genome sequences of human, chimpanzee and macaque. Using computational methods, we identified a total of 280 potential …


Letter From The Dean, Lalit Verma Jan 2009

Letter From The Dean, Lalit Verma

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

No abstract provided.


Molecular Systematics And Phylogeography Of The Genus Richardsonius, Derek Dee Houston Jan 2009

Molecular Systematics And Phylogeography Of The Genus Richardsonius, Derek Dee Houston

UNLV Theses, Dissertations, Professional Papers, and Capstones

The complex geological and climatic events that significantly altered the landscape throughout the Cenozoic Era impacted the diversification of many North American taxa, including freshwater fishes. Here, I employ an array of phylogenetic analyses using a multiple gene tree approach to address several questions regarding the phylogenetic relationships of the North American cyprinid genus Richardsonius and two other closely related genera, Clinostomus and Iotichthys. I also use divergence time estimates generated using fossil calibrations to qualitatively assess the phylogeographic implications of evolution within and among these three genera. Mitochondrial and nuclear DNA sequences show a sister relationship between Iotichthys and …


Historic Genetic Structuring And Paraphyly Within The Great-Tailed Grackle, Jeffrey M. Dacosta, Walter Wehtje, John Klicka Feb 2008

Historic Genetic Structuring And Paraphyly Within The Great-Tailed Grackle, Jeffrey M. Dacosta, Walter Wehtje, John Klicka

Ornithology Program (HRC)

The Great-tailed Grackle (Quiscalus mexicanus) and Boat-tailed Grackle (Q. major) are sister species that have expanded their ranges during historical times. This expansion has created an area of sympatry between these species in Texas and Louisiana, and between distinctive Great-tailed Grackle subspecies in the southwestern United States and northern Mexico. We investigated the evolutionary histories of both species using mitochondrial DNA sequence data and modern phylogenetic methods. Our results reveal genetic structure within Great-tailed, but not Boat-tailed Grackles. Great-tailed Grackles are separated into two clades, but range expansion in the north has led to secondary contact …


Molecular Evolution Of The Cytochrome C Oxidase Subunit 5a Gene In Primates, Monica Uddin, Juan C. Opazo, Derek E. Wildman, Chet C. Sherwood, Patrick R. Hof, Morris Goodman, Lawrence I. Grossman Jan 2008

Molecular Evolution Of The Cytochrome C Oxidase Subunit 5a Gene In Primates, Monica Uddin, Juan C. Opazo, Derek E. Wildman, Chet C. Sherwood, Patrick R. Hof, Morris Goodman, Lawrence I. Grossman

Wayne State University Associated BioMed Central Scholarship

Abstract

Background

Many electron transport chain (ETC) genes show accelerated rates of nonsynonymous nucleotide substitutions in anthropoid primate lineages, yet in non-anthropoid lineages the ETC proteins are typically highly conserved. Here, we test the hypothesis that COX5A, the ETC gene that encodes cytochrome c oxidase subunit 5A, shows a pattern of anthropoid-specific adaptive evolution, and investigate the distribution of this protein in catarrhine brains.

Results

In a dataset comprising 29 vertebrate taxa, including representatives from all major groups of primates, there is nearly 100% conservation of the COX5A amino acid sequence among extant, non-anthropoid placental mammals. The most recent common …


Alfred Russel Wallace: A Capsule Biography, Charles H. Smith Jun 2004

Alfred Russel Wallace: A Capsule Biography, Charles H. Smith

DLPS Faculty Publications

No abstract provided.


Body Mass Of Late Quaternary Mammals (Data Set), Felisa A. Smith, S. Kathleen Lyons, S.K. Morgan Ernest, Kate E. Jones, Kansas State University, Tamar Dayan, Pablo A. Marquet, James H. Brown, John P. Haskell Dec 2003

Body Mass Of Late Quaternary Mammals (Data Set), Felisa A. Smith, S. Kathleen Lyons, S.K. Morgan Ernest, Kate E. Jones, Kansas State University, Tamar Dayan, Pablo A. Marquet, James H. Brown, John P. Haskell

School of Biological Sciences: Faculty Publications

The purpose of this data set was to compile body mass information for all mammals on Earth so that we could investigate the patterns of body mass seen across geographic and taxonomic space and evolutionary time. We were interested in the heritability of body size across taxonomic groups (How conserved is body mass within a genus, family, and order?), in the overall pattern of body mass across continents (Do the moments and other descriptive statistics remain the same across geographic space?), and over evolutionary time (How quickly did body mass patterns iterate on the patterns seen today? Were the Pleistocene …


Mechanical Properties Of The Integument Of The Common Gartersnake, Thamnophis Sirtalis (Serpentes: Colubridae), Gabriel Rivera Jul 2003

Mechanical Properties Of The Integument Of The Common Gartersnake, Thamnophis Sirtalis (Serpentes: Colubridae), Gabriel Rivera

Biological Sciences Theses & Dissertations

The evolution of the ophidian feeding mechanism has involved substantial morphological restructuring associated with the ability to ingest relatively large prey. Previous studies examining the morphological consequences of macrophagy have concentrated on modifications of the skull and cephalic musculature. Although it is evident that macrophagy requires highly compliant skin, the mechanical properties of the ophidian integument have received limited attention, particularly in the context of feeding. I examined mechanical properties of skin along the body axis in male Thamnophis sirtalis (Colubridae). From each of 11 specimens, I examined nine circumferential strips of skin, each spanning 10 ventral scales, spaced at …


Growth And The Expression Of Alternative Life Cycles In The Salamander Ambystoma Talpoideum (Caudata: Ambystomatidae), Travis J. Ryan, Raymond D. Semlitsch Jan 2003

Growth And The Expression Of Alternative Life Cycles In The Salamander Ambystoma Talpoideum (Caudata: Ambystomatidae), Travis J. Ryan, Raymond D. Semlitsch

Scholarship and Professional Work - LAS

Complex life cycles (CLCs) contain larval and adult phases that are morphologically and ecologically distinct. Simple life cycles (SLCs) have evolved from CLCs repeatedly in a wide variety of lineages but the processes that may underlie the transition have rarely been identified or investigated experimentally. We examined the influence of larval growth rate on the facultative expression of alternative life cycles (metamorphosis or maturation as gill-bearing adults [= paedomorphosis]) in the salamander Ambystoma talpoideum. We manipulated growth rates by altering the amount of food individuals received throughout larval development. The expression of alternative life cycles in A. talpoideum is influenced …


Discounting And Reciprocity In An Iterated Prisoner’S Dilemma, David W. Stephens, Colleen M. Mclinn, Jeffrey R. Stevens Jan 2002

Discounting And Reciprocity In An Iterated Prisoner’S Dilemma, David W. Stephens, Colleen M. Mclinn, Jeffrey R. Stevens

Jeffrey Stevens Publications

The Iterated Prisoner’s Dilemma (IPD) is a central paradigm in the study of animal cooperation. According to the IPD framework, repeated play (repetition) and reciprocity combine to maintain a cooperative equilibrium. However, experimental studies with animals suggest that cooperative behavior in IPDs is unstable, and some have suggested that strong preferences for immediate benefits (that is, temporal discounting) might explain the fragility of cooperative equilibria. We studied the effects of discounting and strategic reciprocity on cooperation in captive blue jays. Our results demonstrate an interaction between discounting and reciprocity. Blue jays show high stable levels of cooperation in treatments with …


Avian Prey-Dropping Behavior. I. The Effects Of Prey Characteristics And Prey Loss, Paul V. Switzer, Daniel A. Cristol Jan 1999

Avian Prey-Dropping Behavior. I. The Effects Of Prey Characteristics And Prey Loss, Paul V. Switzer, Daniel A. Cristol

Faculty Research & Creative Activity

No abstract provided.