Keith Karoly

Professor of Biology
Reed College
Portland, OR 97202

Office: Biology, B240

Research Lab.: B238
Phone: (503) 771-1112 ext. 7846
e-mail: Keith.Karoly@directory.reed.edu


Teaching Fall of 2007:

BIO 101 - Introductory Biology
BIO 431 - Ecology & Evolution of Plant-Human Interactions

Spring of 2008:

on leave


EDUCATION
RESEARCH
TEACHING
STUDENT THESES
SELECTED PUBLICATIONS
Karoly-Lab Web
Resources Page


EDUCATION

1985, B. A., Whitman College
1987, M. S., The University of Chicago
1991, Ph. D., The University of Chicago

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RESEARCH

Research in my lab focuses on investigating the ecology and evolution of flowering plants, with a primary emphasis on understanding their reproductive biology. Examples of my research (past and ongoing projects) include:

The Evolution of Floral Morphology in the Mustard Family (Brassicaceae) In collaboration with Jeff Conner (Michigan State Univ. and the Kellogg Biological Station), we have been investigating the evoluiton of stamen position in the mustard family. Our research has focused on understanding the roles of ontogeny, genetic architecture, and natural selection in determining the position of stamens in the mustard flower.

One goal of this collaborative project is to learn the evolutionary explanation for the long-term stasis of a trait that is diagnostic for the Mustard family -- tetradynamous stamens (four stamens with long filaments and two stamens with short filaments). In my Bio 332 course at Reed, we have used artificial selection on plants of the rapid-cycling Brassica rapa lines to demonstrate that the filament length dimorphism that is diagnostic for species in the Musatrd family can be readily altered by selection (see Figure at left; Karoly and Conner, 2000). A similar selection experiment was undertaken in collaboration with the Conner lab using Raphanus raphanistrum. In summer 2002, we placed the divergent lines in field arrays exposed to natural pollination ecology to be able to estimate the strength and direction of natural selection on the filament dimorphism (in a related question, we investigated selection on anther exsertion in summer 2001 - photos from the field). We are currently using genetic markers to determine pollen success for plants from field experiments in 2001 and 2002. This research has been supported by a grant from the Nattional Science Foundation Division of Environment Biology.

We are also investigating the patterns of floral development associated with the origin and subsequent loss of the filament dimorphism as a way to understand the role that development of genetically correlated traits might contribute to the stasis of the filament dimorphism. Results from this work were presented as a research poster at a research conference in Zurich in 2002.



Diversification of Northwest Larkspur. Northwest species in the genus Delphinium appear to be a recently diverged group. Our studies have focused on determining the pattern and causes of diversification for two closely related species, Delphinium nuttallii and Delphinium leucophaeum. Flower color is the primary trait that distinguishes the two taxa, and D. leucophaeum has a very limited distribution and is State-listed endangered in Oregon.

We have used molecular genetic markers (primarily from the chloroplast DNA) to investigate the relationships among popualtions of the two taxa. A phylogeographic analysis of D. nuttallii from throughout its current range suggests that this species has expanded from a Pleistocene refugium in the eastern Columbia River Gorge (Dodd and Karoly, 2000; in prep). Our data for D. leucophaeum suggest that it may have diverged from D. nuttallii during the range expansion of D. nuttallii, making it less than 12,000 years old. Data from our analysis of ribosomal DNA suggests that introgressive hybridization may be occuring between D. nuttalli and D. leucophaeum where their ranges overlap in Washington state.This question is the topic for current research in my lab supported by a grant from the Murdock Foundation.

We are also investigating the biochemical and molecular genetic basis of the flower color difference between these two close relatives. Our crosses suggest that the white-coloration of D. leucophaeum is dominant to the more typical larkspur flower color shown by D. nuttallii. We are investigating pigment chemistry, gene expression and gene squence differenecs for anthocyanin pathway genes for the blue- and white-flowered species, and also looking for ecophysiological differences that might accompany the flower color difference.

Results from both our flower color and phylogeogrpahy research were presented at the EVOWIBO conference in April 2004. Poster contents can be viewed here.




Phylogeography of Garry Oak Garry Oak (Quercus garryana) is the only native oak species currently found from the central Willamette Valley north to British Columbia. Results from our genetic investigations of Northwest larkspur populations led us to wonder if Garry Oak would show the same pattern of refugial isolation that we have observed for the larkspur species that inhabit plant communitites in which the oak is a prominent component. Our initial studies of chloroplast DNA variation have provided a puzzling picture, with the Willamette Valley harboring the only variation we have observed. Lauren Mathewson, Lauren Byerley, and I presented our results at a Native Plant Conference in Corvallis in winter, 2003 (our poster).





Lupinus nanusflowers, being visited by
Apis mellifera. (photo by K. Karoly)



The Evolution of Mixed Mating in an Annual Lupine: Lupinus nanus is an annual lupine that possesses a mixed mating system, meaning that it produces seeds through both self- and cross-pollination. Although its flowers are visited in natural populations by insect pollinators, this species maintains the ability to produce fruit in the absence of pollinator visits. Theoretical models of mating system evolution in plants suggest that mixed mating systems are unstable over the long term. My work with L. nanus and its relatives focused on assessing the evolutionary stability of the mating system and has included determining the rates of cross pollination in natural populations, investigating the selective consequences of self- and cross-pollination, and identifying the floral traits that allow these flowers to produce fruit when they are not visited by pollinators.





Female flowers of Thalictrum pubescens.
(photo by K. Karoly)



Cryptic Dioecy in Tall Meadow Rue: Tall meadow rue (Thalictrum pubescens) is a native perennial of eastern North America that is morphologically androdioecious, but functionally dioecious (separate male and female plants). Female plants make stamens with pollen, but the pollen is believed to be sterile with no direct function. The goal of this research was to understand the evolutionary factors that might maintain sterile stamen and pollen production in females of this species. Field work for this project was conducted at the E. N. Huyck Preserve in New York state.



Karoly Lab.
Web Links		 This page contains a number of links to web sites that have proven useful for me and students in my lab.

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TEACHING

I teach an upper-division course on Vascular Plant Diversity , a sophomore-level course in Molecular Ecology, I participate in the team-taught Introductory Biology course, and I teach advanced seminar courses in topics such as the Ecology and Evolution of Plant Mating Systems, Molecular Genetic Analysis of Plant Evolution , and Ecology and Evolution of Plant-Human Interactions.

 

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RECENT SENIOR THESIS TITLES:

The following is a list of senior theses that have been completed by students in my lab during the past few years. Titles that are underlined serve as links to the Biology Department's web page about senior theses. Clicking on these links will take you to an abstract of that student's thesis. An asterisk (*) following the student's name indicates that the student's thesis research was supported by a grant from the Howard Hughes Undergraduate Research Program, Reed College or the James F. and Marion L. Miller Foundation..

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SELECTED PUBLICATIONS

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Maintained by the Reed College Biology Department
Questions/Comments to Keith.Karoly@directory.reed.edu