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Although
rocky shores account for over 30% of the world's coastlines,
biome level questions and patterns are seldom addressed. My
approach at this large scale focuses on the evolution of
select organisms (mostly Mollusca), the changing habitat,
and the resultant interactions between organisms and between
organisms and the habitat through time.
My interest in this habitat has sustained over 15 years of
research and field work along much of the eastern Pacific
margin, including the Aleutian Islands, Washington State,
the northern and southern California and related island
groups, the islands of Baja California, Mexico, and the
temperate coast of Chile.
Most of my early work consisted of faunal surveys and community level studies with the
California Academy of Sciences. As a graduate student, I
was fortunate to add life history evolution (J.S. Pearse)
and experimental ecology (J.A. Estes) to my basic knowledge
of rocky shore communities. Since coming to Berkeley I have
benefited from exposure and interactions with excellent
paleontologists and evolutionists who have provided new
tools and approaches for my questions.
Research at this scale requires a wide variety of techniques and I often incorporated paleontological, geological, and biogeographical data, in addition to comparative morphology, developmental biology, long-term experimental manipulations, and phylogenetics in my studies. Molecular approaches have been added to this repertoire [visit the Molecular Phylogenetics Laboratory].
Paleontology | Development |  |
| Ecology
| Phylogenetics  |
My work often centers around one of three recurrent themes:
My systematic work features the Patellogastropoda, a group of gastropod molluscs that figure prominently in ecological studies of rocky intertidal communities around the world.
. . . to knock a limpet from the rock does not even require cunning, that lowest power of the mind.
| Charles Darwin, 1834 |
My future systematic research efforts are to construct and
use phylogenetic hypotheses to understand adaptation and
evolution in patellacean faunas in different regions of the
world through time.
These data are used to examine
evolutionary and biogeographical patterns in other rocky
intertidal taxa, and preliminary data suggest that some
of these patterns are common to
several unrelated molluscan groups.
I also continue to investigate the relationships amongst higher molluscan taxa including subclades within the Gastropoda, the "conchiferian" groups, and the phyletic position of the Mollusca. Data sets include morphological characters, molecular characters and fossil and Recent taxa, providing a total evidence approach.
My work on the evolution of the rocky intertidal settings is downsizing, but I remain interested in the role of substrate in determining and augmenting community composition and subsequent species interactions.
My newest research project is actually a return to my dissertation work and seeks to determine the role of heterochrony in
the evolution of life history strategies and reproductive
systems in molluscs.
In contrast to my earlier studies of marine gastropods,
this new project will use land snails as the model system. This project is made
possible by Research Associate Dr.
Barry Roth's vast knowledge of land snail reproductive morphology and his phylogenetic analyses of various Californian clades. This project will combine the
requiste ancestor-descendant relationships with developmental patterns in
reproductive (and other select organ systems) to identify modifications in the
developmental pathways that produce the complex reproductive
tracts seen in these pulmonate snails.
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