Robert W. Hoshaw Memorial Scholarship Archive

2015:

Paul CaraDonna

My research aims to understand the structure and function of ecological communities and species interactions, mostly with plants and pollinators. In doing so, I explore the interplay among biotic context, abiotic variation, and species’ phenologies. I ask how these factors influence plant and animal populations, their interactions, and community structure from a basic ecological perspective and under rapid climate change scenarios.

 

Julie Messier

My dissertation research explores the limits of a trait-based approach to plant ecology by testing its implicit and explicit assumptions. Do do so, I studied the variation and co-variation of physiological trait across biological scales in temperate trees. My work indicates that considering individual variation, phenotypic complexity (integration and multi-dimensionality) and the scale dependence of patterns and processes is key to developing a robust trait-based ecology. juliemessier.org

 

2013:

Guanhzu Han

My research addresses the emergence and evolution viruses. Typically, viruses evolve rapidly, which makes it difficult to study their long-term evolution by using contemporary virus sequences. Endogenous viral elements replicate with their hosts' genomes and evolve relatively slowly, preserving the features of ancient viruses. My research involves discovering novel endogenous viral elements within animal genomes to study the deep history of viruses. My other interests include molecular evolutionary analysis of contemporary virus sequences to understand the tempo and mode in virus evolution.

 

2012:

Jennifer Hughes Wisecaver

My dissertation research was on chloroplast evolution and horizontal gene transfer in dinoflagellates, a large group of unicellular eukaryotes common in nearshore, marine environments and known for causing harmful algal blooms (red tides). As part of my research, I used comparative genomics and phylogenomics to identify and quantify cases of horizontal gene transfer (transmission of DNA between different genomes) in dinoflagellates. Over 15% of dinoflagellate genes, including those responsible for toxin production, are derived from bacteria, indicative of rampant horizontal gene transfer in dinoflagellates. For my postdoctoral research I am studying the evolution of secondary metabolic gene clusters in fungi and plant genomes. http://as.vanderbilt.edu/rokaslab/

 

2008:

Joel Wertheim

 

Matt Herron

My Ph.D. research combined comparative and experimental approaches to understand the evolution of multicellularity and cellular differentiation in the volvocine algae (Volvox and its close relatives). The experimental portion of this research was an artificial selection experiment on a partially differentiated volvocine alga, Pleodorina starrii. I selected independent populations of P. starrii for increased and decreased size in two environments (still and mixed medium) and measured the effect on the proportion of cells differentiated as sterile soma. In the comparative portion of my dissertation, I reconstructed the developmental changes making up the transition from single-celled to multicellular forms in a time-calibrated, phylogenetic framwork. This work showed that some important traits, including cellular differentiation, had multiple, independent origins, as well as reversions from derived back to ancestral states. In addition, estimates of divergence times showed that the origin of multicellularity in this group was at least four times older than previously thought, that the transition to functionally integrated multicellular forms was surprisingly rapid, and that several lineages have been morphologically stable for over 100 million years. Collectively these results make up the most complete and detailed timeline available for any major evolutionary transition.

The central question motivating my current research is how do simple organisms evolve into complex organisms? I approach this question using experimental evolution, genetic analyses, and gene expression studies, with the following goals:

1) Evolve simple multicellularity in two different selective regimes. As a first step in addressing the evolution of complexity, I am using the unicellular green alga Chlamydomonas reinhardtii to experimentally generate a de novo origin of simple (undifferentiated) multicellularity.

2) Ascertain the genetic bases and evolutionary dynamics underlying the evolution of multicellularity. To discover the genetics underlying multicellularity in this system, I am comparing evolved multicellular and ancestral unicellular strains using a combination of whole genome sequencing, gene expression analyses, and backcrosses to ancestral strains.

3) Evaluate the roles of phenotypic plasticity in the evolution of differentiated multicellularity. I will address two questions related to phenotypic plasticity. First, does phenotypic plasticity facilitate the evolution of cellular differentiation? Second, can simple multicellularity evolve via genetic assimilation?

http://www.eebweb.arizona.edu/grads/mherron/

 

2007:

Nate Swenson

Patrick Degnan

 

2006:

Jeff Good

I received the Robert W. Hoshaw award in 2006 while working in Michael Nachman’s lab on the genetics of speciation in mice. The primary goal of my dissertation was to resolve the genetic basis of male sterility in hybrid mice. I remember this as a very exciting time in speciation research. The recent development of new genomic resources in mice provided a powerful complement to traditional genetic approaches, making it feasible to dissect the genetic basis of complex phenotypes. Ultimately I found that hybrid male sterility was linked to disrupted gene regulation on the X chromosome during a critical step of spermatogenesis. These results provided one of the first direct links between the evolution of this important developmental process and the formation of new species.

It was a privilege to pursue my Ph.D. in the EEB department and receiving the Hoshaw award stands as one of my most meaningful academic achievements. After graduation I continued my research on reproduction and speciation through an international postdoc fellowship at the Max Planck Institute for Evolutionary Anthropology. Now as a faculty member at the University of Montana my lab continues to use evolutionary genetics and genomics to understand speciation and adaptation in animals.

http://good-lab.dbs.umt.edu/Good_Lab/Home.html

 

2005:

Laura Carsten Conner

Laura Carsten Conner is a Research Assistant Professor and Director of Outreach for the College of Natural Science and Mathematics at the University of Alaska Fairbanks.  Her research focuses on the development of science identities among girls, and the building of conceptual knowledge in immersive environments.  Conner currently leads a GK-12 outreach program as well as several summer programs for youth.  While at the University of Arizona, Carsten Conner worked in Dan Papaj’s lab, where she studied how sperm competition influences male reproductive traits, with a special emphasis on the flexibility of those traits. She earned her Ph.D. in 2007.

http://www.uaf.edu/cnsm-outreach/outreach-office/laura-conner-bio/

 

2004:

Jessie Cable

 

2003:

Asher Cutter

When I received the R.W. Hoshaw Award in 2003, my thesis research focused on two areas: genome evolution in the nematode Caenorhabditis elegans and on understanding population sex ratio using C. elegans. Evolutionary genomics was new and exciting, with some of the first means of integrating information on gene expression and sequence changes on a genome-wide scale. And, C. elegans was a magnificent but neglected evolutionary experimental system that I exploited to test and parameterize theory about the role of outcrossing sex within populations that don’t actually need mating partners to reproduce. This work shaped the foundation of all my subsequent research, from my postdoc fellowship in Edinburgh to my current lab at the University of Toronto. I’m continuing to push hard on the Caenorhabditis study system to understand the microevolutionary forces that shape population genomic change, the genetics underlying behavioral divergence and speciation, and higher level biodiversity by discovering and analyzing new species around the world.

http://labs.eeb.utoronto.ca/cutter

 

Jake Russel:

When I received the Hoshaw award my research focus I studied maternally transmitted symbionts of aphids in the laboratory of Nancy Moran. My goals were to elucidate their functions, their capacity for spread across species, and their histories of interactions across the aphids. We found that some of these symbionts may protect aphids from high temperatures and that these bacteria have frequently undergone host-switching across aphid species. Furthermore, we demonstrated through lab experiments that symbionts seem readily capable of stably colonizing new host aphids after experimental transfer.

I am currently studying these symbionts in natural populations of pea aphids, in an attempt to quantify their natural dynamics and the forces that likely drive these dynamics. I also study symbiotic gut communities of various animals, including ants. While not ubiquitous, several groups of ants appear to engage in long-standing symbioses with specialized gut bacteria. We are currently studying the functional roles of these microbes as a way to better understand the roles of bacteria in ant ecology and evolution.

http://www.pages.drexel.edu/~jar337/index.html
 

2001: 

Don Falk

Don Falk is Associate Professor in the University of Arizona School of Natural Resources and the Environment, with joint appointments in the Laboratory of Tree-Ring Research and the Institute of the Environment. Don’s research focuses on fire history, fire ecology, and restoration ecology in a changing world. Falk is a AAAS Fellow, and has received the Fulbright Short-Term Scholar award, the Ecological Society of America’s Deevey Award for outstanding graduate work in paleoecology, and awards from his School for both Outstanding Scholarly contributions and Outstanding Course (Introduction to Wildland Fire). In an earlier life Don was co-founder and Executive Director of the Center for Plant Conservation, originally at Arnold Arboretum of Harvard University and now at Missouri Botanical Garden; he served subsequently as the first Executive Director of the Society for Ecological Restoration International (SER), of which he was also a founding Board member. His recent books include Foundations of Restoration Ecology (edited with Margaret Palmer and Joy Zedler), and The Landscape Ecology of Fire (edited with Don McKenzie and Carol Miller). Don is a member of the Executive Board of the Southwest Fire Science Consortium.

2000:

Eileen Hebets

 

1999:

Betsy Arnold

Betsy Arnold came to EEB after completing her undergraduate studies at Duke and a post-baccalaureate position at the Smithsonian Tropical Research Institute in Panama. Her dissertation work focused on the diversity and ecological roles of fungal endophytes, which are now acknowledged as one of the most ubiquitous groups of plant symbionts. After completing her degree under the mentorship of Lucinda McDade, Betsy returned to Duke as an NSF Microbial Biology postdoc to study the evolution of endophytism. With François Lutzoni she expanded her focus to include endophytes in temperate and boreal biomes, and endophyte-like symbionts in lichens. She joined the faculty in Plant Sciences at the UA in 2005. She is now an Associate Professor and serves as Curator of the Gilbertson Mycological Herbarium. She is an award-winning teacher, mentors graduate students and postdocs, and has been recognized for her outstanding contributions to mycology through both national and international awards. More information can be found on her labs website

www.arnoldlab.net

www.enDOBiodiversity.org

 

1998:

Patrick Abbot

When I received the award, I was finishing up work on trying to define clone-specific molecular markers in a species of "social" aphid. These aphids live in groups composed of a single reproductive female and her daughters. The female produces these daughters asexually. Thus, sociality in these clonal groups seemed to confirm aspects of Hamilton's theory for the evolution of altruism in highly-related groups. Anecdotal evidence had suggested, however, that individual aphids move between groups, reducing relatedness. But by how much? What was the pattern? Only molecular markers could answer such questions. After 4 difficult years, I finally had success in the lab, and the results were published in PNAS about the same time that the award was announced. I completely surprised when I heard that I would receive the award. After being quite certain that I was a complete failure after 4 years of struggle, it remains one of my most cherished accomplishments. 

Information about my current work can be found on my lab website: http://www.vanderbilt.edu/abbotlab/Home.html

 

1997:

Yaron Ziv

One of the major challenges in ecology is to explore large-scale biodiversity patterns, which are dependent on ecological and evolutionary processes operating at multi scales.  For my PhD in EEB I designed, implemented and run a spatially explicit, multi-species, process-based, object-oriented landscape simulation model (SHALOM), building upon major lessons from fields such as metapopulation dynamics and landscape ecology.  Processes of SHALOM are modeled on local (habitat match, saturation, competition) and global (fitness-optimizing migration and environmental stochasticity) scales.  Simulation results showed that habitat heterogeneity and allometric differences between species are enough to produce some common large-scale patters, such as the long-normal relationship between body size and species abundance.  Results also provided important insights regarding landscape-oriented community structure under different scale-dependent processes. More information on my current work can be found on my lab’s website: http://lifeserv.bgu.ac.il/wb/yziv/

 

1996:

Andrea Lloyd

When I received the Hoshaw Scholarship, I was working on my dissertation research on the paleoecology of treeline forests in the eastern Sierra Nevada.   I used tree rings to reconstruct the historical pattern of range expansions and contractions of foxtail pine (Pinus balfouriana) during the late Holocene.  At many sites in the eastern Sierra Nevada, dead 'ghost forests' of foxtail pine still persist above the current elevation of treeline.  Using tree-ring dating, I was able to determine that the trees in these forests died off during a period of very dry conditions approximately 1,000 years ago.   My dissertation research verified the importance of climate as a long-term control over treeline position, but yielded the unexpected insight that dry conditions— as well as cold conditions— could lead to a contraction of treeline.

What am i doing now?
I have been on the faculty of Middlebury College since the fall of 1996— immediately after finishing my dissertation.  I have taught in Biology and in the Program in Environmental Studies, including courses in ecology and evolution, plant community ecology, ecological history, and global change biology.  My research has explored questions of forest response to recent climate warming in the Arctic— primarily in Alaska, but also in Siberia.  Since 2012, I have served as the Dean of the Faculty at Middlebury. More information can be found on my lab’s website:  http://sites.middlebury.edu/tree-ring-lab/

 

Mark Fishbein

As a graduate student in EEB in the early-mid 1990s, I conducted research on plant pollination and the evolution of floral displays (the natural arrangement of flowers on a plant into different sized bunches).  I conducted these studies on a native milkweed called butterflyweed (Asclepias tuberosa) at The Nature Conservancy's Canelo Hills Preserve, on the west side of the Huachuca Mountains.  The motivation of this work was to test how sexual selection operates in plants that have both male and female reproductive structures on the same individual.  I also conducted a phylogenetic study of the milkweeds, based on study of morphological characteristics of over 100 species, which involved fieldwork throughout the US and northwest Mexico.

 http://fishbein.okstate.edu

 

1995:

Elizabeth Sandlin

 

1994:

Susan Schwinning