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Evolution Commons™

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2015

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Articles 121 - 125 of 125

Full-Text Articles in Evolution

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 Sex Determination And The Dmrt1 Gene In The Japanese Gecko (Gekko Japonicus), Lisa-Marie Mullen Jan 2015

The Evolution Of Sex Determination And The Dmrt1 Gene In The Japanese Gecko (Gekko Japonicus), Lisa-Marie Mullen

All Master's Theses

There are different sex-determining mechanisms in our environment, which are separated into two groups known as genotypic sex determination (GSD) and environmental sex determination. The most well-known mechanism in the ESD group is temperature-dependent sex determination (TSD). In this study, the presence of the Doublesex and mab-3-related Transcription Factor (Dmrt1) gene was observed during embryonic development in geckos with a TSD mechanism. To do this, I observed the rate of transcription of the Dmrt1 gene in the Gecko species Gekko japonicus. Pregnant geckos were caught around Nanjing, China. Once the females laid their eggs, the eggs were …

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Nonstructural Carbohydrate Concentrations Of Pine Trees As A Function Of Evolutionary History, Joshua T. Mims Jan 2015

Nonstructural Carbohydrate Concentrations Of Pine Trees As A Function Of Evolutionary History, Joshua T. Mims

College of Graduate Studies: Theses & Dissertations

Nonstructural carbohydrates (NSC) can supply substrate during periods when current photosynthate is unavailable or inadequate to meet metabolic demands. I hypothesized that natural selection has favored higher nonstructural carbohydrate concentrations ([NSC]) in species that have an evolutionary history of frequent disturbance and tested this using three southern pine species that have evolved under a continuum of disturbance frequencies (evolutionary history of fire ~ longleaf > slash > loblolly). Stem and root samples were collected from 12 similar-sized individual trees of each species during time periods that reflect the annual minimum and maximum [NSC]. A modified colorimetric method was performed on the samples …

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