Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 2 of 2
Full-Text Articles in Life Sciences
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, …
Infrageneric Relationships Within Collomia (Polemoniaceae), Eric Stewart Green
Infrageneric Relationships Within Collomia (Polemoniaceae), Eric Stewart Green
Theses and Dissertations
Traditional evolutionary models depict evolution as a bifurcating pattern with a single ancestor diverging to form two lineages. However, reticulate species resulting from hybridization and recombination have unique histories shared with two independent lineages, not one. Accounting for the genetic histories of reticulate species increases the power and ability to recover biologically meaningful relationships. The genus Collomia (Polemoniaceae) is used to explore issues of reticulation and the importance of accounting for gene histories in a phylogenetic analysis. The issue of reticulation within species trees is discussed with a multilabeled, network approach being explored to better represent the genus's evolutionary history. …