Upcoming Events

Kerry Whittaker: "International Relations? Exploring Global Population Structure, Succession, and Dispersal in a Marine Diatom Species"

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March 5, 2015 4:00 PM  – 5:00 PM
Druckenmiller Hall, Room 020

Marine diatoms exhibit astounding levels of diversity; the extent and distribution of this diversity over space and time plays an important role in determining their contribution to ocean productivity and potential to adapt to environmental change. 

Using molecular tools, Kerry Whittaker studies the extent and distribution of diatom diversity across the globe. Diatoms are the most diverse group of algae, with an estimated 100,000 species thought to exist. Yet, the factors of the marine environment driving and supporting this high level of diversity are little understood. Exploring the ways in which diatom populations are connected across large spatial scales, and over time, provides important insight into the interactions between diatoms, their evolution, and the marine environment. 

Kerry Whittaker currently teaches marine science at Coastal Studies for Girls in Freeport, Maine, and is an adjunct professor at Bowdoin this semester where she teaches Evolution. Kerry recently moved to Maine after spending a year as a Knauss Fellow in Washington D.C. working with NOAA on the ESA listing of marine species and the conservation policy behind marine populations. In 2014, she received her PhD in Oceanography from the Graduate School of Oceanography, URI, and is interested in environmental selection, phytoplankton evolution, geneflow in the ocean, and the adaptive potential of marine organisms.

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Sarah Schaack: "Understanding Mutational Dynamics Over Short and Long Time Scales"

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March 26, 2015 4:00 PM  – 5:00 PM
Druckenmiller Hall, Room 020

Despite the importance of understanding the mechanisms and consequences of mutation, few parameters related to the rate, spectrum, and effects of spontaneous mutation have been estimated. In this talk, Sarah Schaack discusses the dynamics of mutation at small and large scales, within and between lineages, over short and long time periods of time (e.g., empirically-derived estimates of base substitution rates to reports of frequent horizontal transfer among eukaryotes).   

She presents a few short vignettes to highlight the utility of using a variety of study systems and approaches to tackling questions related to understanding the accrual, maintenance, and loss of genotypic and phenotypic mutational variance genome-wide. She also highlights her recent work on the dynamics of mobile DNA (transposable elements and endogenous viruses) which constitute a very significant portion, and in many cases the majority, of the genome in most plants and animals.

Schaack is assistant professor of Biology at Reed College in Portland, Oregon

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Ian Davison, Boston University

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April 2, 2015 4:00 PM  – 5:00 PM
Druckenmiller Hall, Room 020

Ian Davison, Boston University

Our lab studies the neural basis of sensory perception. How does the brain take millions of discrete pieces of raw sensory information, streaming in from primary receptor neurons, and synthesize them into a single unified percept? This process is the foundation of our sensory experience, and our aim is to describe the underlying neural circuit computations.

 

We study this problem in the olfactory system for several reasons. First, smell is highly synthetic. Odors are immediately experienced as a single percept, despite the fact that natural odors often contain dozens of chemical components, and are detected by hundreds of different types of odorant receptors. Second, the olfactory circuit is compact, reducing the path over which information flow needs to be traced: only two synapses separate receptors in the nose from integrative processing in cortical regions. Finally, olfactory associations are notoriously strong and rapid, offering a promising window for understanding how experience is written into the brain's internal structure.

 

To better understand how complex sensory inputs are recognized and stored by networks of neurons, we measure and manipulate the activity of neural populations with both electrophysiological and optical approaches. This is complemented by quantitative behavior, reporting the animal's sensory experience, and by precise measures of circuit connectivity with intracellular physiology in vitro. Ultimately we hope to use olfaction to help reveal some of the brain's general mechanisms for flexible sensory processing, pattern recognition, and neural information storage.

 

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Marshall Iliff, '97 Cornell University

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April 2, 2015 6:30 PM  – 8:30 PM
Searles Science Building, Room 315

Marshall Iliff began birding at age 11 and has been birding obsessively ever since. After college he conducted several years of ornithological field work across the US and in Mexico, often working and traveling with Chris and Brian. He has worked on three state records committees, as North American Birds Regional Editor for two different regions on two different coasts, as well as on a number of other articles and books relating to birds, bird identification, and bird distribution. From 2000-2007 he was a full-time tour leader for Victor Emanuel Nature Tours, traveling across the United States and Canada, as well as through much of Central America and Mexico, and even as far as Kenya. Regretting his intermittent note taking through all those travels, he is making up for it now by entering whatever old checklists he can find into eBird!

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Mark Patterson, Northeastern University "Perforate and imperforate body plans in scleractinian corals: implications for coping with environmental stress"

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April 16, 2015 4:00 PM  – 5:00 PM
Druckenmiller Hall, Room 020

The physical biology of invertebrates (sponges, cnidarians, squid), plants (macroalgae, sunflowers, seagrasses), and fishes is another area in which I am broadly interested. The allometry of metabolism is an area where I apply chemical engineering theory to lower aquatic invertebrates and algae. Contrary to the predictions of “universal scaling laws” that have appeared in the literature, e.g., the West, Brown, Enquist (WBE) theory, these taxa do not follow 3/4 power scaling of metabolic rate with body mass. Instead they exhibit a diversity of scaling exponents for which I have developed a predictive theory based on first principles from fluid transport and mass transfer. This “flow modulated allometry” model is now being tested in my laboratory and in the field using the NOAA underwater habitat Aquarius. Since 1984, I have used saturation underwater habitats to conduct research in situ on corals and their allies. Recent work using Aquarius has examined how reef corals respond to water motion during bleaching episodes by altering their photobiology and expression of stress proteins. Our lab has recently developed a predictive electrical network model of the gastrovascular system of corals of the two types of coral bauplan, perforate (where an extensive plumbing connects the polyps) and imperforate (where polyps are not connected directly). This model will help us understand how corals respond to environmental stress including that posed by global warming and ocean acidification.

 

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Ron Peck, Colby College

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April 23, 2015 4:00 PM  – 5:00 PM
Druckenmiller Hall, Room 020

Research Interests: Physiology and molecular biology of microbes in extreme environments; novel mechanisms of regulation in biochemical pathways

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Brad Davidson, Swarthmore College "Mitotic tuning: cell division modulates inductive signals during early heart development"

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April 30, 2015 4:00 PM  – 5:00 PM
Druckenmiller Hall, Room 020

Currently, our research is focused on revealing the precise function of FGF in early heart development. We have demonstrated that FGF signaling causes a group of 4 founder cells to undergo an asymmetric division. The smaller daughters of this division respond to continued FGF signaling by activating heart genes and migrating towards the site of future heart formation while the larger daughter form tail muscle.
Through transgenic manipulations, we can disrupt FGF signaling specifically in these four cells, blocking heart development. Conversely, we can activate downstream factors and cause the entire group of cells to migrate and form extra heart tissue (above image). We are also able to isolate Ciona heart cells and examine lineage-specific gene expression. This analysis employs micro-arrays designed to probe all predicted coding regions in the Ciona genome. Through these techniques we have identified an extensive set of heart genes up-regulated by FGF. Future studies will focus on determining the role of these FGF target genes in heart development as well as identifying the precise transcriptional mechanisms by which FGF and downstream factors co-ordinate heart gene expression.

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