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University of Nebraska - Lincoln

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Articles 31 - 60 of 88

Full-Text Articles in Evolution

Changes In Male Hunting Returns, Raymond B. Hames Dec 2016

Changes In Male Hunting Returns, Raymond B. Hames

Department of Anthropology: Faculty Publications

Research on changes in male hunting among hunter-gatherers addresses two important issues in early human evolution: the nature of the family and trade-offs in mating and parenting effort as well as the development of embodied capital. In the hunter-gatherer literature, there is a debate about the function of male hunting that has implications for understanding the role males play in the evolution of the pair bond. The traditional model argues that male hunting and other economic activities are forms of male provisioning or parenting effort designed to enhance a man’s fitness through his wife’s reproduction and the survivorship of their …

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Inter- And Intra-Individual Variation In Predator-Related Behavioral Plasticity Expressed By Female Green Swordtails (Xiphophorus Hellerii), Rachael A. Disciullo Nov 2016

Inter- And Intra-Individual Variation In Predator-Related Behavioral Plasticity Expressed By Female Green Swordtails (Xiphophorus Hellerii), Rachael A. Disciullo

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

Phenotypic plasticity is the ability of one genotype to express multiple phenotypes under variable environments. Behavioral plasticity is a type of phenotypic plasticity in which individuals adjust behavior in response to changes in environment. Often, behavioral plasticity is studied at the level of the population, rather than at the level of the individual. Further, few studies have considered the effect of individual traits, such as size and age, on the expression of behavioral plasticity, or, how individual plasticity may be correlated across different contexts. In this study, we used female green swordtails (Xiphophorus hellerii) to test the effects …

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The Maintenance Of Phenotypic Divergence Through Sexual Selection: An Experimental Study In Barn Swallows Hirundo Rustica, Rebecca Safran, Yoni Vortman, Brittany R. Jenkins, Joanna K. Hubbard, Matt Wilkins, Rachel J. Bradley, Arnon Lotem Jul 2016

The Maintenance Of Phenotypic Divergence Through Sexual Selection: An Experimental Study In Barn Swallows Hirundo Rustica, Rebecca Safran, Yoni Vortman, Brittany R. Jenkins, Joanna K. Hubbard, Matt Wilkins, Rachel J. Bradley, Arnon Lotem

School of Biological Sciences: Faculty Publications

Previous studies have shown that sexual signals can rapidly diverge among closely related species. However, we lack experimental studies to demonstrate that differences in trait-associated reproductive performance maintain sexual trait differences between closely related populations, in support for a role of sexual selection in speciation. Populations of Northern Hemisphere distributed barn swallows Hirundo rustica are closely related, yet differ in two plumage-based traits: ventral color and length of the outermost tail feathers (streamers). Here we provide experimental evidence that manipulations of these traits result in different reproductive consequences in two subspecies of barn swallow: (H. r. erythrogaster in North …

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Proximate And Evolutionary Causes Of Sexual Size Dimorphism In The Crab Spider Mecaphesa Celer, Marie Claire Chelini Jul 2016

Proximate And Evolutionary Causes Of Sexual Size Dimorphism In The Crab Spider Mecaphesa Celer, Marie Claire Chelini

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

Animal species’ body sizes result from the balance between selection for survival and selection for reproduction. In species with sexual size dimorphism (SSD), this balance differs between females and males, resulting in distinct sizes despite similar constraints. I used an integrative approach to understand how sexual section, and differences in developmental trajectories and metabolic physiology, resulted in the female biased SSD of the crab spider Mecaphesa celer (Thomisidae). SSD in spiders is often assumed to be a consequence of selection for early male maturation, which should provide males with additional mating opportunities. My results allow us to discard mate …

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The North American Grouse: Their Biology And Behavior, Paul A. Johnsgard Jun 2016

The North American Grouse: Their Biology And Behavior, Paul A. Johnsgard

Zea E-Books Collection

The ten currently recognized species of grouse in North America have played an important role in America’s history, from the famous but ill-fated heath hen, a primary source of meat for the earliest New England immigrants, to the ruffed grouse, currently one of the most abundant and soughtafter upland game birds in more than 40 states and provinces. This book summarizes the ecology, reproductive biology, and social behavior of all ten of the extant North American grouse species. It also describes the current status of grouse populations, some of which are perilously close to extinction. The social behavior of grouse …

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Molecular Evolution And Functional Divergence Of Trace Amine–Associated Receptors, Seong-Il Eyun, Hideaki Moriyama, Federico G. Hoffmann, Etsuko N. Moriyama Mar 2016

Molecular Evolution And Functional Divergence Of Trace Amine–Associated Receptors, Seong-Il Eyun, Hideaki Moriyama, Federico G. Hoffmann, Etsuko N. Moriyama

School of Biological Sciences: Faculty Publications

Trace amine-associated receptors (TAARs) are a member of the G-protein-coupled receptor superfamily and are known to be expressed in olfactory sensory neurons. A limited number of molecular evolutionary studies have been done for TAARs so far. To elucidate how lineage-specific evolution contributed to their functional divergence, we examined 30 metazoan genomes. In total, 493 TAAR gene candidates (including 84 pseudogenes) were identified from 26 vertebrate genomes. TAARs were not identified from non-vertebrate genomes. An ancestral-type TAAR-like gene appeared to have emerged in lamprey.We found four therian-specific TAAR subfamilies (one eutherian-specific and three metatherian- specific) in addition to previously known nine …

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Benefits Of Size Dimorphism And Copulatory Silk Wrapping In The Sexually Cannibalistic Nursery Web Spider, Pisaurina Mira, Alissa G. Anderson, Eileen Hebets Feb 2016

Benefits Of Size Dimorphism And Copulatory Silk Wrapping In The Sexually Cannibalistic Nursery Web Spider, Pisaurina Mira, Alissa G. Anderson, Eileen Hebets

Eileen Hebets Publications

In sexually cannibalistic animals, male fitness is influenced not only by successful mate acquisition and egg fertilization, but also by avoiding being eaten. In the cannibalistic nursery web spider, Pisaurina mira, the legs of mature males are longer in relation to their body size than those of females, and males use these legs to aid in wrapping a female’s legs with silk prior to and during copulation. We hypothesized that elongated male legs and silk wrapping provide benefits to males, in part through a reduced likelihood of sexual cannibalism. To test this, we paired females of random size with …

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Intertemporal Similarity: Discounting As A Last Resort, Jeffrey R. Stevens Jan 2016

Intertemporal Similarity: Discounting As A Last Resort, Jeffrey R. Stevens

Jeffrey Stevens Publications

Standard models of intertemporal choice assume that individuals discount future payoffs by integrating reward amounts and time delays to generate a discounted value. Alternative models propose that, rather than integrate across them, individuals compare within attributes (amounts and delays) to determine if differences in one attribute outweigh differences in another attribute. For instance, Leland (2002) and Rubinstein (2003) propose models that 1) compare the two reward amounts to determine whether they are similar, 2) compare the similarity of the two time delays, and then 3) make a decision based on these similarity judgments. Here, I tested discounting models against attribute-based …

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The Domain Specificity Of Intertemporal Choice In Pinyon Jays, Jeffrey R. Stevens, Bryce Kennedy, Dina Morales, Marianna Burks Jan 2016

The Domain Specificity Of Intertemporal Choice In Pinyon Jays, Jeffrey R. Stevens, Bryce Kennedy, Dina Morales, Marianna Burks

Jeffrey Stevens Publications

When choosing between a piece of cake now versus a slimmer waistline in the future, many of us have difficulty with self-control. Food-caching species, however, regularly hide food for later recovery, sometimes waiting months before retrieving their caches. It remains unclear whether these long-term choices generalize outside of the caching domain. We hypothesized that the ability to save for the future is a general tendency that cuts across different situations. To test this hypothesis, we measured and experimentally manipulated caching to evaluate its relationship with operant measures of self-control in pinyon jays (Gymnorhinus cyanocephalus). We found no correlation …

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Reflections Of The Social Environment In Chimpanzee Memory: Applying Rational Analysis Beyond Humans, Jeffrey R. Stevens, Julian N. Marewski, Lael J. Schooler, Ian C. Gilby Jan 2016

Reflections Of The Social Environment In Chimpanzee Memory: Applying Rational Analysis Beyond Humans, Jeffrey R. Stevens, Julian N. Marewski, Lael J. Schooler, Ian C. Gilby

Jeffrey Stevens Publications

In cognitive science, the rational analysis framework allows modelling of how physical and social environments impose information-processing demands onto cognitive systems. In humans, for example, past social contact among individuals predicts their future contact with linear and power functions. These features of the human environment constrain the optimal way to remember information and probably shape how memory records are retained and retrieved. We offer a primer on how biologists can apply rational analysis to study animal behaviour. Using chimpanzees (Pan troglodytes) as a case study, we modelled 19 years of observational data on their social contact patterns. Much …

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Cognitive Phenotypes And The Evolution Of Animal Decisions, Tamra C. Mendelson, Courtney L. Fitzpatrick, Mark E. Hauber, Charles H. Pence, Rafael L. Rodriguez, Rebecca J. Safran, Caitlin A. Stern, Jeffrey R. Stevens Jan 2016

Cognitive Phenotypes And The Evolution Of Animal Decisions, Tamra C. Mendelson, Courtney L. Fitzpatrick, Mark E. Hauber, Charles H. Pence, Rafael L. Rodriguez, Rebecca J. Safran, Caitlin A. Stern, Jeffrey R. Stevens

Jeffrey Stevens Publications

Despite the clear fitness consequences of animal decisions, the science of animal decision making in evolutionary biology is underdeveloped compared with decision science in human psychology. Specifically, the field lacks a conceptual framework that defines and describes the relevant components of a decision, leading to imprecise language and concepts. The ‘judgment and decision-making’ (JDM) framework in human psychology is a powerful tool for framing and understanding human decisions, and we apply it here to components of animal decisions, which we refer to as ‘cognitive phenotypes’. We distinguish multiple cognitive phenotypes in the context of a JDM framework and highlight empirical …

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The Evolution Of Aquatic Mammals Toward A Nearly Universal Large Size? Evidence From Phylogenetics And Fossils, William Gearty, Craig R. Mcclain, Jonathan Payne Jan 2016

The Evolution Of Aquatic Mammals Toward A Nearly Universal Large Size? Evidence From Phylogenetics And Fossils, William Gearty, Craig R. Mcclain, Jonathan Payne

School of Biological Sciences: Presentations

Most mammal species live on land, but the largest mammals live in the oceans. Aquatic and terrestrial habitats clearly impose differing selective pressures on body size. However, the quantitative study of body size evolution in mammals and other major animal clades typically focuses on either terrestrial or marine clades independently, thus failing to capture the dynamics of size evolution associated with the transition between land and water. Consequently, the extent to which the rate, magnitude, and outcome of size change associated with habitat transitions are shared among clades remains unknown, leaving open the question of whether the apparently common phenomenon …

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Comparative Anatomy Of The Bony Labyrinth Of Extant And Extinct Porpoises (Cetacea: Phocoenidae), Rachel A. Racicot, William Gearty, Naoki Kohno, John J. Flynn Jan 2016

Comparative Anatomy Of The Bony Labyrinth Of Extant And Extinct Porpoises (Cetacea: Phocoenidae), Rachel A. Racicot, William Gearty, Naoki Kohno, John J. Flynn

School of Biological Sciences: Faculty Publications

The inner ear anatomy of cetaceans, now more readily accessible by means of nondestructive high-resolution X-ray computed tomographic (CT) scanning, provides a window into their acoustic abilities and ecological preferences. Inner ear labyrinths also may be a source for additional morphological characters for phylogenetic analyses. In this study, we explore digital endocasts of the inner ear labyrinths of representative species of extinct and extant porpoises (Mammalia: Cetacea: Phocoenidae), a clade of some of the smallest odontocete cetaceans, which produce some of the highest-frequency clicks for biosonar and communication. Metrics used to infer hearing ranges based on cochlear morphology indicate that …

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Ecology And Morphology Of The Late Miocene Musk Deer, Longirostromeryx Wellsi (Artiodactyla: Moschidae: Blastomerycinae), Katheryn Y. C. Chen Aug 2015

Ecology And Morphology Of The Late Miocene Musk Deer, Longirostromeryx Wellsi (Artiodactyla: Moschidae: Blastomerycinae), Katheryn Y. C. Chen

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Longirostromeryx wellsi, one of the latest surviving members of the extinct clade Blastomerycinae (Artiodactyla: Moschidae), possesses highly derived craniodental morphology that deviates from typical musk deer form. Previous work suggests that the unique anatomy of L. wellsi represents adaptations for occupying open savannas. To test this hypothesis I conduct principal components analysis on five postcranial bones of L. wellsi, comparing them to that of several extant ruminant artiodactyls, which are divided among seven habitat categories. These elements are also compared with the postcrania of other blastomerycines. These analyses indicate that L. wellsi anatomy is most similar to that of other …

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Multimodal Signalling In The North American Barn Swallow: A Phenotype Network Approach, Daizaburo Shizuka, Matthew R. Wilkins, Maxwell Joseph, Joanna K. Hubbard, Rebecca Safran Jan 2015

Multimodal Signalling In The North American Barn Swallow: A Phenotype Network Approach, Daizaburo Shizuka, Matthew R. Wilkins, Maxwell Joseph, Joanna K. Hubbard, Rebecca Safran

Papers in Behavior in Biological Sciences

Complex signals, involving multiple components within and across modal- ities, are common in animal communication. However, decomposing complex signals into traits and their interactions remains a fundamental challenge for studies of phenotype evolution. We apply a novel phenotype network approach for studying complex signal evolution in the North American barn swallow (Hirundo rustica erythrogaster). We integrate model testing with correlation-based phenotype networks to infer the contributions of female mate choice and male–male competition to the evolution of barn swallow communication. Overall, the best predictors of mate choice were distinct from those for competition, while moderate functional overlap suggests …

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Evolution In Action: Climate Change, Biodiversity Dynamics And Emerging Infectious Disease, Eric P. Hoberg, Daniel R. Brooks Jan 2015

Evolution In Action: Climate Change, Biodiversity Dynamics And Emerging Infectious Disease, Eric P. Hoberg, Daniel R. Brooks

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Climatological variation and ecological perturbation have been pervasive drivers of faunal assembly, structure and diversification for parasites and pathogens through recurrent events of geographical and host colonization at varying spatial and temporal scales of Earth history. Episodic shifts in climate and environmental settings, in conjunction with ecological mechanisms and host switching, are often critical determinants of parasite diversification, a view counter to more than a century of coevolutionary thinking about the nature of complex host–parasite assemblages. Parasites are resource specialists with restricted host ranges, yet shifts onto relatively unrelated hosts are common during phylogenetic diversification of parasite lineages and directly …

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Genetically Based Low Oxygen Affinities Of Felid Hemoglobins: Lack Of Biochemical Adaptation To High-Altitude Hypoxia In The Snow Leopard, Jan E. Janecka, Simone S. E. Nielsen, Sidsel D. Andersen, Federico G. Hoffmann, Roy E. Weber, Trevor Anderson, Jay F. Storz, Angela Fago Jan 2015

Genetically Based Low Oxygen Affinities Of Felid Hemoglobins: Lack Of Biochemical Adaptation To High-Altitude Hypoxia In The Snow Leopard, Jan E. Janecka, Simone S. E. Nielsen, Sidsel D. Andersen, Federico G. Hoffmann, Roy E. Weber, Trevor Anderson, Jay F. Storz, Angela Fago

School of Biological Sciences: Faculty Publications

Genetically based modifications of hemoglobin (Hb) function that increase blood–O2 affinity are hallmarks of hypoxia adaptation in vertebrates. Among mammals, felid Hbs are unusual in that they have low intrinsic O2 affinities and reduced sensitivities to the allosteric cofactor 2,3-diphosphoglycerate (DPG). This combination of features compromises the acclimatization capacity of blood–O2 affinity and has led to the hypothesis that felids have a restricted physiological niche breadth relative to other mammals. In seeming defiance of this conjecture, the snow leopard (Panthera uncia) has an extraordinarily broad elevational distribution and occurs at elevations above 6000 m in the Himalayas. Here, …

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The Evolution Of Respiratory O2/No Reductases: An Out-Of-The-Phylogenetic-Box Perspective, Anne-Lise Ducluzeau, Barbara Schoepp-Cothenet, Robert Van Lis, Frauke Baymann, Michael J. Russell, Wilfgang Nitschke Jun 2014

The Evolution Of Respiratory O2/No Reductases: An Out-Of-The-Phylogenetic-Box Perspective, Anne-Lise Ducluzeau, Barbara Schoepp-Cothenet, Robert Van Lis, Frauke Baymann, Michael J. Russell, Wilfgang Nitschke

Department of Biochemistry: Faculty Publications

Complex life on our planet crucially depends on strong redox disequilibria afforded by the almost ubiquitous presence of highly oxidizing molecular oxygen. However, the history of O2-levels in the atmosphere is complex and prior to the Great Oxidation Event some 2.3 billion years ago, the amount of O2 in the biosphere is considered to have been extremely low as compared with present-day values. Therefore the evolutionary histories of life and of O2-levels are likely intricately intertwined. The obvious biological proxy for inferring the impact of changing O2-levels on life is the evolutionary history …

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Early Song Discrimination By Nestling Sparrows In The Wild, Daizaburo Shizuka Jun 2014

Early Song Discrimination By Nestling Sparrows In The Wild, Daizaburo Shizuka

School of Biological Sciences: Faculty Publications

Songs play an important role in premating isolation in birds. However, when songs are learned, expe- rience with both conspecific and heterospecific songs in early life could lead to the development of both mixed songs and mixed preferences. One way that such learning errors can be prevented is if birds can discriminate between songs of different species prior to learning and preferentially memorize conspe- cific songs. Prior captive studies have shown that white-crowned sparrows, Zonotrichia leucophrys, are able to discriminate songs early in the process of song memorization, after about 10 days since hatching. I studied early song discrimination in …

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A Male Spider’S Ornamentation Polymorphism Maintained By Opposing Selection With Two Niches, Bo Deng, Alex Estes, Brett Grieb, Douglas Richard, Brittney Hinds, Eileen Hebets May 2014

A Male Spider’S Ornamentation Polymorphism Maintained By Opposing Selection With Two Niches, Bo Deng, Alex Estes, Brett Grieb, Douglas Richard, Brittney Hinds, Eileen Hebets

Eileen Hebets Publications

The Levene mechanism to maintain genotypic polymorphism by opposing selection on genotypes in multiple niches was proposed 60 years ago, and yet no systems were found to satisfy the mechanisms rather restrictive conditions. Reported here is such an example that a wolf spider population lives in a habitat of mixed rocks and leafy litter for which the females are phenotypically indistinguishable and the males have two distinct phenotypes subject to opposing selection with respect to the substrates. Census data is best-fitted to a population genetics model of the Levene type. A majority of the best fit support polymorphism, with many …

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Evolutionary Pressures On Primate Intertemporal Choice, Jeffrey R. Stevens May 2014

Evolutionary Pressures On Primate Intertemporal Choice, Jeffrey R. Stevens

Department of Psychology: Faculty Publications

From finding food to choosing mates, animals must make intertemporal choices that involve fitness benefits available at different times. Species vary dramatically in their willingness to wait for delayed rewards. Why does this variation across species exist? An adaptive approach to intertemporal choice suggests that time preferences should reflect the temporal problems faced in a species' environment. Here, I use phylogenetic regression to test whether allometric factors (relating to body size), relative brain size, and social group size predict how long 13 primate species will wait in laboratory intertemporal choice tasks. Controlling for phylogeny, a composite allometric factor that includes …

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Body Size And Species Richness Changes In Glyptosaurinae (Squamata: Anguidae) Through Climatic Transitions Of The North American Cenozoic, Sara Elshafie Apr 2014

Body Size And Species Richness Changes In Glyptosaurinae (Squamata: Anguidae) Through Climatic Transitions Of The North American Cenozoic, Sara Elshafie

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Poikilothermic vertebrates offer excellent climate proxies based on relationships between environment and measurable variables such as body size and species richness. Relationships of these variables in lizards to environmental transitions over long time scales are poorly understood. Here I show that patterns of body size and species richness in a lizard clade, Glyptosaurinae (Squamata: Anguidae), correspond to known histories of paleotemperatures through the Cenozoic of North America. Glyptosaurines have the richest fossil record among North American Cenozoic lizards and exhibit a wide range of skull sizes. In order to estimate body size for glyptosaurines and other fossil anguids, I collected …

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Fossil Crocodilians From The High Guajira Peninsula Of Colombia, And The History Of Neogene Crocodilian Diversity In Tropical South America, Jorge W. Moreno-Bernal Apr 2014

Fossil Crocodilians From The High Guajira Peninsula Of Colombia, And The History Of Neogene Crocodilian Diversity In Tropical South America, Jorge W. Moreno-Bernal

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

The greatest diversity of Cenozoic crocodilians occurred during the Miocene in equatorial South America. However, the origin of this high diversity and its relationship to environmental factors are poorly understood. Most described species come from localities assigned to Laventan (13.8-11.8 Ma) and Huayquerian (9.0-6.8 Ma) South American land mammal ages (SALMAS), whereas the record is sparse in the early to middle Miocene and after the latest Miocene and Pliocene. Field research in the Castilletes (early Miocene-Pliocene) Formation in the High Guajira Peninsula of Colombia provides new fossil data on the origin of Neotropical crocodylian diversity. The Castilletes Formation crops out …

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Stress Responses And Energy Storage In Drosophila Melanogaster Selected For Resistance To A Gram-Positive Bacillus Cereus Spores, Zhen Hu Apr 2014

Stress Responses And Energy Storage In Drosophila Melanogaster Selected For Resistance To A Gram-Positive Bacillus Cereus Spores, Zhen Hu

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

A survival response study was carried out by using D. melanogaster and the opportunistic pathogen B. cereus as the agent of selection. The spores of B. cereus, a gram-positive bacteria that can cause the human pathogen disease, were applied in our artificial laboratory selection. Selected lines were treated with B. cereus spores. Wound control lines were punctured with a needle dipped into sterile H2O. Control lines did not apply any treatment. Three different environmental treatments were used within each line type (autoclaved spores of B.cereus, sterile H2O and no treatment). The autoclaved spores were …

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Patterns Of Maximum Body Size Evolution In Cenozoic Land Mammals: Eco-Evolutionary Processes And Abiotic Forcing, Juha J. Saarinen, Alison G. Boyer, James H. Brown, Daniel P. Costa, S.K. Morgan Ernest, Alistair R. Evans, Mikael Fortelius, John L. Gittleman, Marcus J. Hamilton, Larisa E, Harding, Kari Lintulaakso, S. Kathleen Lyons, Jordan G. Okie, Richard M. Sibly, Patrick R. Stephens, Jessica Theodor, Mark D. Uhen, Felisa A. Smith Jan 2014

Patterns Of Maximum Body Size Evolution In Cenozoic Land Mammals: Eco-Evolutionary Processes And Abiotic Forcing, Juha J. Saarinen, Alison G. Boyer, James H. Brown, Daniel P. Costa, S.K. Morgan Ernest, Alistair R. Evans, Mikael Fortelius, John L. Gittleman, Marcus J. Hamilton, Larisa E, Harding, Kari Lintulaakso, S. Kathleen Lyons, Jordan G. Okie, Richard M. Sibly, Patrick R. Stephens, Jessica Theodor, Mark D. Uhen, Felisa A. Smith

School of Biological Sciences: Faculty Publications

There is accumulating evidence that macroevolutionary patterns of mammal evolution during the Cenozoic follow similar trajectories on different continents. This would suggest that such patterns are strongly determined by global abiotic factors, such as climate, or by basic eco-evolutionary processes such as filling of niches by specialization. The similarity of pattern would be expected to extend to the history of individual clades. Here, we investigate the temporal distribution of maximum size observed within individual orders globally and on separate continents. While the maximum size of individual orders of large land mammals show differences and comprise several families, the times at …

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The Roles Of Phenotypic Plasticity And Genotypic Specialization In High Altitude Adaptation, Danielle M. Tufts Dec 2013

The Roles Of Phenotypic Plasticity And Genotypic Specialization In High Altitude Adaptation, Danielle M. Tufts

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

In vertebrates living at high altitude, arterial hypoxemia may be ameliorated by reversible changes in the oxygen-carrying capacity of the blood (regulated by erythropoiesis) and/or changes in blood–oxygen affinity (regulated by allosteric effectors of hemoglobin function). These hematological traits often differ between taxa that are native to different elevational zones, but it is often unknown whether the observed physiological differences reflect fixed, genetically based differences or environmentally induced acclimatization responses (phenotypic plasticity). Here, we report measurements of hematological traits related to blood–O2 transport in populations of deer mice (Peromyscus maniculatus) that are native to high- and low-altitude …

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The Origin And Molecular Evolution Of Two Multigene Families: G-Protein Coupled Receptors And Glycoside Hydrolase Families, Seong-Il Eyun Aug 2013

The Origin And Molecular Evolution Of Two Multigene Families: G-Protein Coupled Receptors And Glycoside Hydrolase Families, Seong-Il Eyun

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

Multigene family is a group of genes that arose from a common ancestor by gene duplication. Gene duplications are a major driving force of new function acquisition. Multigene family thus has a fundamental role in adaptation. To elucidate their molecular evolutionary mechanisms, I chose two multigene families: chemosensory receptors and glycoside hydrolases. I have identified complete repertoires of trace amine-associated receptors (TAARs), a member of chemosensory receptors, from 38 metazoan genomes. An ancestral-type TAAR emerged before the divergence between gnathostomes (jawed vertebrates) and sea lamprey (jawless fish). Primary amine detecting TAARs (TAAR1-4) are found to be older and have evolved …

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Predation And Behavioral Plasticity In Green Swordtails: Mate Choice In Females And Exploratory Behavior In Males, Andrew J. Melie May 2013

Predation And Behavioral Plasticity In Green Swordtails: Mate Choice In Females And Exploratory Behavior In Males, Andrew J. Melie

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

Two studies were carried out with green swordtails, Xiphophorus helleri, to investigate the effect of predation on swordtail behavior, and to determine how behavioral plasticity operates in both a mate choice and an anti-predator context. Male green swordtails vary in colorful conspicuous traits, e.g. the colorful dorsal fin and sword. Female swordtails have a preexisting bias for males with a sword, and prefer long-sworded males to short-sworded males, but this preference is plastic. The first study examined predator-related plasticity in the behavior of males differing in size. Smaller males showed greater behavioral plasticity; they were more active in the …

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Spontaneous Male Death And Monogyny In The Dark Fishing Spider Dolomedes Tenebrosus Hentz, 1843 (Araneae, Pisauridae), Steven K. Schwartz Apr 2013

Spontaneous Male Death And Monogyny In The Dark Fishing Spider Dolomedes Tenebrosus Hentz, 1843 (Araneae, Pisauridae), Steven K. Schwartz

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

Male animals typically attempt to mate with multiple females in order to increase their reproductive success. In some species, however, males instead invest in fertilizing the eggs of a single female. Monogyny (male monogamy) is found in a diverse assemblage of taxa, and recent theoretical work reveals that a male-biased sex ratio can favor the evolution of this relatively rare mating system. We integrate this theoretical framework with field observations and laboratory experiments involving the sexually size dimorphic fishing spider, Dolomedes tenebrosus. Results from mating trials revealed a novel form of self-sacrifice behavior where males spontaneously die when they …

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Melanin Concentration Gradients In Modern And Fossil Feathers, Daniel J. Field, Liliana D’Alba, Jakob Vinther, Samuel M. Webb, William Gearty, Matthew D. Shawkey Mar 2013

Melanin Concentration Gradients In Modern And Fossil Feathers, Daniel J. Field, Liliana D’Alba, Jakob Vinther, Samuel M. Webb, William Gearty, Matthew D. Shawkey

School of Biological Sciences: Faculty Publications

In birds and feathered non-avian dinosaurs, within-feather pigmentation patterns range from discrete spots and stripes to more subtle patterns, but the latter remain largely unstudied. A ,55 million year old fossil contour feather with a dark distal tip grading into a lighter base was recovered from the Fur Formation in Denmark. SEM and synchrotron-based trace metal mapping confirmed that this gradient was caused by differential concentration of melanin. To assess the potential ecological and phylogenetic prevalence of this pattern, we evaluated 321 modern samples from 18 orders within Aves. We observed that the pattern was found most frequently in distantly …

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