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David M. Rosenthal |
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Portland
State University (503)
869 8855 drosen@pdx.edu |
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General Research Areas : ecological genetics, plant physiological ecology and evolution in plants |
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Ecological Genetics was largely defined by E.B. Ford in his classic book by the same name. He described the field over 40 years ago as “the experimental study of evolution and adaptation carried out by means of combined field-work and laboratory genetics”. Phenotypic and underlying genetic variation within and among populations is the currency of evolution. Understanding the nature of this variation informs us about how plants will respond to selection pressures (i.e. water, temperature, light, competition, herbivory). Plant physiological ecology examines the relationship between plant structure, functional traits and the surrounding environment. Functional or ecophysiological traits are those involved in resource uptake (eg, water, nutrients, light, CO2 ), allocation of these resources to metabolism (defense, growth, turgor pressure) and ultimately to reproduction (fitness). The sessile nature of almost all terrestrial plants makes them particularly interesting since they must be reasonably well suited (i.e. adapted) to their habitats in order to thrive. In fact, many ecophysiological traits undergo adaptive evolution so that a given phenotype enhances performance in its native habitat relative to other phenotypic states (e.g. where are cactus leaves gone?). Therefore we expect functional traits to vary among populations, habitats and species. When trait expression covaries with environmental variables and fitness we can test adaptive hypotheses regarding these traits. This in turn teaches us about past selection pressures and can help us predict evolutionary trajectories. In summary, ecophysiological traits are central to understanding evolutionary mechanisms or forces that underlie plant adaptations and ecological genetics informs us about the nature of this adaptive variation. Current Research Areas: Origins, Ecological Genetics, and
Evolution of a Newly Invasive Grass: As a postdoctoral researcher in Mitch Cruzan’s lab I am studying the evolutionary potential of a newly invasive grass using quantitative genetic (phenotype) and ecological genetic (genotype) approaches. This perennial bunchgrass is native to North Africa, Europe and Asia and is spreading in Oregon. Small populations are also known from California and suitable habitats exist throughout the pacific northwest suggesting this weed will continue to spread. Hybridization, Morphological Divergence
and Adaptation: My dissertation research in plant variation grew from my studies of phenotypic variation in natural hybrid sunflowers. I utilized hybridizing plants as a framework to study plant variation, adaptation and speciation. I identified putatively adaptive functional traits in wild sunflowers using both observational and experimental approaches. Our analyses of variation in ecophysiological and life history traits in natural and synthetic hybrids has demonstrated that hybridization was a catalyst for phenotypic and ecological divergence that led to speciation in this group.
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Research
• Publications • Presentations • Education • Other |
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