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Biology

Brigham Young University

Speciation

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Full-Text Articles in Life Sciences

Life History Divergence In Livebearing Fishes In Response To Predation: Is There A Microevolution To Macroevolution Barrier?, Mark C. Belk, Spencer J. Ingley, Jerald B. Johnson May 2020

Life History Divergence In Livebearing Fishes In Response To Predation: Is There A Microevolution To Macroevolution Barrier?, Mark C. Belk, Spencer J. Ingley, Jerald B. Johnson

Faculty Publications

A central problem in evolutionary biology is to determine whether adaptive phenotypic variation within species (microevolution) ultimately gives rise to new species (macroevolution). Predation environment can select for trait divergence among populations within species. The implied hypothesis is that the selection resulting from predation environment that creates population divergence within species would continue across the speciation boundary such that patterns of divergence after speciation would be a magnified accumulation of the trait variation observed before speciation. In this paper, we test for congruence in the mechanisms of microevolution and macroevolution by comparing the patterns of life history divergence among three …


Repeated Trait Evolution Driven By Divergent Natural Selection At Early And Late Stages Of Speciation, Spencer J. Ingley Oct 2015

Repeated Trait Evolution Driven By Divergent Natural Selection At Early And Late Stages Of Speciation, Spencer J. Ingley

Theses and Dissertations

Speciation – the process by which new species arise – is of fundamental importance in the biological sciences. The means by which new species arise, and the relationship among living species, has been a topic that has captivated both lay and scientific observers for centuries. In recent years, the study of speciation has enjoyed increased attention, resulting in significant advances in our understanding of how species form. Although our understanding of the processes that contribute to speciation has increased dramatically in recent years, our knowledge of how reproductive barriers accumulate as speciation proceeds is still limited. Thus, studies that evaluate …


Diversification And Conservation In The South American Dry Biomes: Distribution Modeling And Multilocus Lizard Phylogeography, Fernanda Werneck Jul 2012

Diversification And Conservation In The South American Dry Biomes: Distribution Modeling And Multilocus Lizard Phylogeography, Fernanda Werneck

Theses and Dissertations

The understanding of diversification of intraspecific lineages can shed light on speciation processes and ultimately biogeographic patterns across multiple spatial and temporal scales. In this dissertation I investigated the geographical and ecological factors promoting diversification across the South American dry diagonal biomes (i.e. Cerrado, Chaco, and Seasonally Dry Tropical Forests - SDTFs), through a coupled approach between multilocus phylogeographic and geospatial methods, in the larger context of interpreting the consequences of the resulting patterns for the conservation of biodiversity and evolutionary processes. In Chapter 1 I evaluate biogeographic hypotheses previously proposed and emphasize that the dry diagonal biomes are particularly …


Species Trees And Species Delimitation With Multilocus Data And Coalescent-Based Methods: Resolving The Speciation History Of The Liolaemus Darwinii Group (Squamata, Tropiduridae), Arley Camargo Bentaberry Feb 2011

Species Trees And Species Delimitation With Multilocus Data And Coalescent-Based Methods: Resolving The Speciation History Of The Liolaemus Darwinii Group (Squamata, Tropiduridae), Arley Camargo Bentaberry

Theses and Dissertations

The inference of species boundaries and phylogenetic relationships are fundamental for evolutionary, ecological, and conservation studies. The resolution of species boundaries and the inference of phylogenetic relationships among species are required to define the units of analysis and to find the most closely related units for evaluating alternative models of speciation. I highlight lizards as model organisms for ecological and evolutionary studies, emphasizing their contributions to advances in understanding linkages between phylogeography and speciation. In this dissertation, I focus on the phylogenetic relationships of the lizards in the Liolaemus darwinii group, and the species boundaries of a nested clade within …


Assessing Traditional Morphology- And Chemistry-Based Species Circumspections In Lichenized Ascomycetes: Character Evolution And Molecular Species Delimitation In Common Western North American Lichens, Steven Leavitt Jul 2010

Assessing Traditional Morphology- And Chemistry-Based Species Circumspections In Lichenized Ascomycetes: Character Evolution And Molecular Species Delimitation In Common Western North American Lichens, Steven Leavitt

Theses and Dissertations

Accurate species delimitation has critical implications for ecological and conservation studies; and for understanding factors driving diversification. However, a growing body of evidence indicates that morphology-based species circumspection in lichenized ascomycetes often fails to accurately represent the number of fungal species. The use of molecular data in lichen systematics provides an important alternative to traditional morphological characters for identifying natural groups and assessing evolutionary histories in challenging lichen taxa. In this work, I examined two common lichen-forming genera in western North America, Rhizoplaca and Xanthoparmelia, as models for investigating character evolution, species delimitation in morphologically and chemically diverse species, …