Contact
Information:
Deborah Marr
Associate Professor of Biology
Department of Biological Sciences, Indiana University
1700 Mishawaka Avenue, P.O. Box 7111, South Bend, Indiana 46634
Tel: (574) 520-5564; Fax: (574) 520-4482
email: dmarr@iusb.edu
B.S. Binghamton
University, Binghamton, New York
Ph.D. Indiana
University Bloomington, Bloomington, Indiana University
Postdoctoral
Associate, Vanderbilt University, Nashville, Tennessee
Courses Research Publications
Courses
Click here for Official
Course Descriptions
Introduction
to the Biological Sciences (L101)
L101 is the first semester of the Introductory Biology sequence and emphasizes
principles in Ecology, Mendelian and Population Genetics, and Evolution.
Prerequisites include Level 4 on the mathematics placement exam (0r a passing
grade in M107) and either one year of high school chemistry or one semester of
college chemistry. This course is designed for students considering careers in
the Biological Sciences. Offered Fall and Spring semesters. (5 cr)
Introduction
to Biological Sciences (L102)
L102 is the second semester of the Introductory Biology sequence and emphasizes
principles of cell structure and function, metabolism, and plant and animal
physiology. Prerequisites include Level 4 on the mathematics placement
exam (0r a passing grade in M107) and either one year of high school chemistry
or one semester of college chemistry. This course is designed for students
considering careers in the Biological Sciences. Offered Fall and Spring
semesters. (5 cr)
Environmental Biology (N390)
Environmental Biology focuses on the
interactions between humans and the environment with emphasis on population,
community, and ecosystem levels of ecology. Credit is not allowed toward the biology major. Minimum prerequisites include one
semester of University-level Science (any 100 level or higher course in
Biology, Chemistry, Geology, or Physics).
This course fulfills the N390 Natural World General Education
requirement, and requirements for the Environmental Studies Minor. (3 cr)
Ecology (L473)
In this course we will consider the abiotic and biotic interactions that affect
species distribution, abundance, and diversity at the levels of individual,
population, and community. Prerequisites include Biology L101, L102,
Chemistry C105/C125, C106/C126, and 6 credits of any upper level Biology (200
level or higher). Offered alternate Fall semesters (Odd years). (3 cr)
Laboratory
in Ecology (L474)
Field and laboratory study of populations, communities and ecosystems.
Emphasis on experiment design, data analysis, and learning field and lab
techniques used in Ecological Research. L473 is a Corequisite (or
Prerequisite). Offered alternate Fall Semesters (Odd years). (2 cr)
D503
- Master of Liberal Studies Science Seminar: Food, Science, and Society
Food, Science, and Society is a graduate seminar that focuses on the history of
human diet, origins and methods of agriculture, and development of cuisines in
different cultures. The emphasis of this course will be on how science
(and a scientific approach) informs our understanding of these issues, how
science is used in development of public policy and marketing, and how cultural
perspectives influence the approach and questions that scientists ask. (3
cr)
Research
I study the ecology and evolution of species interactions with a particular interest
in the effect interactions have on plant reproductive traits, factors that
affect the rate of disease spread in plant populations, and looking at how
community context affects species interactions (for example, the effect of
plant diversity on plant-fungal interactions or plant-insect interactions).
Below I briefly introduce each system and provide an overview of ongoing and
past projects. Contact me if you are interested in learning more about
opportunities to participate in undergraduate research projects during summer,
Fall, or Spring semester.
Ecological causes of seed size variation
in species of Hydrophyllum
Many plant species exhibit little
variation in seed size, however there are some species in which seed size
varies 10 fold or more. The persistence of this variation is intriguing
because both empirical and theoretical studies predict that seed size should be
less variable compared to other reproductive traits because larger seeds
generally have higher fitness within species. Previous studies by Loren
Wolfe of Hydrophyllum
appendiculatum, an understory herb common in the midwestern United States,
have shown 10-fold variation in seed mass, and those larger seeds have greater
reproductive success as adults. In my lab we are studying the effects of
wilting disease (most likely caused by Fusarium species) on seed size and other
reproductive traits in three species of Hydrophyllum.
Currently, we are identifying
undescribed Fusarium
species associated with species of Hydrophyllum using morphological (culturing
fungal isolates on several types of media) and molecular techniques (DNA
sequencing).
Student researchers on the Hydrophyllum project:
Tim Greenlee pollinating H. canadense Michelle
Marshall tracking wilt in H. appendiculatum
Ecological and genetic comparisons of the
plant community in remnant and restored prairie sites in Northwestern Indiana
In collaboration with Andrew Schnabel
(Indiana University South Bend) and Rebecca Dolan (Butler
University), we are comparing specific aspects of the ecology and genetics of
plant communities in restored tallgrass prairies to that of native, remnant
prairies surrounding the restoration site. This study is being done at a
large scale prairie and savanna restoration that is being done by the Nature
Conservancy in Newton County, IN. Specifically we are studying how well
the species composition and diversity of the reconstructed communities match
those of remnant sites and of the seed mixes that are being planted into each
restored area. Second, to assess persistence of individual species over
time, we will select four species for detailed demographic monitoring, which
will include studies of flowering, pollination, seed set, herbivory, and
seedling recruitment. Third, because genetic variation is necessary for
short-term and long-term adaptation to environmental change, we are testing for
loss of genetic diversity and increases in inbreeding in reconstructed
populations relative to remnant populations that served as seed sources for the
restoration.
Marijana Guard, Stuart Orr Kari
Kubalanza Jon
Loftus, Stuart Orr
Cool finds in the
prairie (caterpillar found near Asclepias
incarnata, swamp milkweed)
Silene acaulis and anther smut
disease: effects of a pollinator-transmitted disease on host reproduction
and pattern of disease spread
Silene
acaulis is a long-lived
alpine plant that can be infected by a fungus (Microbotryum violaceum) that causes
anther smut disease. Diseased plants are often completely sterilized and
have flowers that produce fungal spores AND can attract pollinators (see
picture below). Reproduction in healthy plants depends on pollinators
transporting pollen, but they may also receive fungal spores that could
potentially cause life-long sterility. The intriguing biology of this
plant and fungus allowed me to address three general issues: the
reproductive success of healthy individuals that have diseased neighbors, the
effect of a sexually transmitted disease on the evolution of mating systems,
and spatial factors affecting disease spread and host population growth. (Photo shows plant with anther smut
disease. The anthers are filled
with dark purple fungal spores (for contrast, see photo below of healthy
hermaphrodite and yellow pollen).
One outcome of this work is that
the annual rate of disease spread in S. acaulis is low; between 0-1% new infections
occur per year. In collaboration with Lynda
Delph, we studied the temporal dynamics of S. acaulis and M. violaceum at sites located in central
Colorado to address the longer-term effects these two species have on each
other's populations.
Healthy hermaphrodite
Yuccas and yucca moths: the role of
mutualists and cheaters and their effect on reproduction in Yucca filamentosa
Yucca
filamentosa and the yucca
moth Tegeticula
yuccasella also have an intriguing relationship in that the plant is
exclusively pollinated by the moth, and the moth's offspring are solely
dependent on the yucca's developing seeds for food. In collaboration with Olle
Pellmyr, we have studied on three aspects of this interaction: (1)
the consequences of moth pollinating behavior on the genetic structure of the
seed population, (2) interactions between pollinators and cheaters whose larvae
feed side by side in yucca fruits, and (3) the plant physiological mechanisms
that limit the number of eggs a moth can lay in the ovary before triggering
flower abscission.
An
example from Kankakee Sands in Indiana; Restoration Ecology, Published online: 12-Nov-2007. doi:
10.1111/j.1526-100X.2007.00318.x
Marr DL and Marshall ML (2006) Effect of a fungal pathogen
on floral size and seed size in Hydrophyllum appendiculatum. American
Journal of Botany, 93: 389-398. pdf file
Marr DL (2006) Seed fitness of hermaphrodites in areas with females and anther
smut disease: Silene acaulis and Microbotryum violaceum. New Phytologist,
169: 741-752.
pdf file
Marr DL and Delph LF (2005) Spatial and temporal pattern of a
pollinator-transmitted pathogen in a long-lived perennial (Silene
acaulis). Evolutionary Ecology Research 7: 335-352. pdf file
Marr DL and Pellmyr O (2003) Effect of pollinator-inflicted ovule damage on
floral abscission in the yucca-yucca moth mutualism: the role of
mechanical and chemical factors. Oecologia 136: 236-243.
Grens A, Marr D, Schnabel A (2002) Writing in the Sciences. Pages 636-639
in Coleman, B., R. Brittenham, S. Campbell, and S. Girard, editors.
Making Sense: Constructing Knowledge in the Arts and Sciences.
Houghton Mifflin Company, Boston, MA.
Marr DL, Brock MR, Pellmyr O (2001) Coexistence of mutualists and
antagonists: exploring the impact of cheaters on the Yucca-yucca moth
mutualism. Oecologia 128: 454-463.
Marr DL, Leebens-Mack J, Elms L, Pellmyr O (2000) Pollen dispersal in
Yucca filamentosa (Agavaceae): the paradox of self-pollination behavior
by Tegeticula yuccasella (Prodoxidae). American Journal of Botany 87:
670-677.
Delph LF, Bailey MF, Marr DL (1999) Seed provisioning in gynodioecious Silene
acaulis (Caryophyllaceae). American Journal of Botany 86: 140-144.
Marr DL (1998) The effect of Microbotryum violaceum spores on pollen
germination in Silene acaulis. International Journal of Plant Science
159: 221-227.
Marr DL (1997) Impact of a pollinator-transmitted disease on reproduction
in healthy Silene acaulis. Ecology 78: 1471-1480.
Marr DL, Devine TE, Parker MA (1997) Nodulation restrictive genotypes of
Glycine and Amphicarpaea: a comparative analysis. Plant and Soil
189: 181-188.
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