Evolutionary Shifts Associated with Substrate Endemism in the Western American Flora
Evolutionary Shifts Associated with Substrate Endemism in the Western American Flora By Adam Christopher Schneider A dissertation submitted in partial satisfaction of the Requirements for the degree of Doctor of Philosophy in Integrative Biology in the Graduate Division of the University of California, Berkeley Committee in charge: Professor Bruce Baldwin, Chair Professor Brent Mishler Professor Kip Will Summer 2017 Evolutionary Shifts Associated with Substrate Endemism in the Western American Flora Copyright © 2017 by Adam Christopher Schneider Abstract Evolutionary Shifts Associated with Substrate Endemism in the Western American Flora by Adam Christopher Schneider Doctor of Philosophy in Integrative Biology University of California, Berkeley Professor Bruce G. Baldwin, Chair This study investigated how habitat specialization affects the evolution and ecology of flowering plants. Specifically, a phylogenetic framework was used to investigate how trait evolution, lineage diversification, and biogeography of the western American flora are affected by two forms of substrate endemism: (1) edaphic specialization onto serpentine soils, and (2) host specialization of non-photosynthetic, holoparasitic Orobanchaceae. Previous studies have noted a correlation between presence on serpentine soils and a suite of morphological and physiological traits, one of which is the tendency of several serpentine-tolerant ecotypes to flower earlier than nearby closely related populations not growing on serpentine. A phylogenetically uncorrected ANOVA supports this hypothesis, developed predominantly through previously published comparisons of conspecific or closely related ecotypes. However, comparisons among three models of trait evolution, as well as phylogenetic independent contrasts across 24 independent clades of plants that include serpentine tolerant species in California and with reasonably resolved phylogenies, revealed no significant affect of flowering time in each of these genera.
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