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Published: June 13, 2011

Aaron Olsen defends his dissertation proposal

John Bates, Curator and Section Head, Life Sciences, Negaunee Integrative Research Center

One exciting and rewarding part of our jobs as curators at The Field Museum is having the opportunity to advise graduate students.  I’ve been a member of the Committee on Evolutionary Biology at the University of Chicago for more than 14 years.  All doctoral students need an advisor and then he/she has to form a committee of additional professors/curators who will advise on the dissertation/thesis.  Last Thursday, I went down to the U of C campus to hear Aaron Olsen defend his doctoral dissertation proposal having been asked to be a member of his committee. 

Aaron did a public defense, which means an announcement was made to all the Biology related departments at the University of Chicago and to members of the Committee on Evolutionary Biology.  At 1:00 in a meeting room filled with professors and fellow graduate students, Aaron’s major advisor, Field Museum Curator of Fishes, Mark Westneat, introduced him and Aaron presented on how for his dissertation he plans to study the physics associated with the operation of bird bills, focusing on the multiple joints where the maxilla and mandible articulate with other bones of the skull.  Aaron had already sent a digital copy of his proposal to all his committee and what he did in his 45 minute talk was present this proposal to those in the room after which people were able to ask questions and then we had a closed meeting with just Aaron and his committee.  The other members of the committee include Mark, Melina Hale, and Callum Ross, Melina and Callum are in the U of C department of Organismal Biology and Anatomy.  The reason for a graduate student’s committee is to provide a spectrum of opinions and experience to help the student design the best possible dissertation.  Ultimately, it will be the committee who signs off on the dissertation for the University, so this is an important responsibility.  I can’t claim to be an expert fully on the details associated with the phyisical and mechanical interactions of the muscles and bones in bird’s bill, but the other three committee members study such questions in a variety of ways on their study groups.  One thing I love about being on a committee is getting the opportunity to learn myself.  I am the only ornithologist, so I can help with insight based on what I know of the avian literature and through my experiences of studying birds around the world and in our collections. 

            Aaron has designed a project that will take extensive advantage of the skeleton collection in the Bird Division (one of the largest and best in the world).  He wants to use cutting edge techniques, some of which he is developing himself, to gather the data to better understand how the morphology of bills and heads of birds with very different foraging behaviors, from seed-eating finches, to insectivorous warblers, probing shorebirds, and fish-eating herons operate.  Coupled with studies like the Early Bird Tree of Life project, Aaron’s studies will provide new insight into avian evolution and ecology.  They also can be compared and contrasted with similar surveys of other groups like Fish, which Mark Westneat has undertaken to tell us more about evolution in general.

Some images of skulls Aaron has taken along with the Phylogenetic tree based on Early Bird data (Image by A. Olsen).

            Aaron did a great job with his presentation, his proposal, and in his meeting with his committee afterward, so the committee has communicated this to the university and Aaron will now get on to the hard (and fun) stuff, gathering and analyzing all the data he needs to test various hypotheses about how the bills of birds really operate.   Along the way he’ll teach everyone around him about what he learns, including me.  Some things won’t work out like he wanted and new questions will undoubtedly appear, but having the honor and responsibility of helping develop future generations of scientists studying our collections in new ways is something that never gets old.


John Bates
Curator and Section Head, Life Sciences

Contact Information

The tropics harbor the highest species diversity on the planet.  I am most intrigued by evolution at the tips of the tree of life.  My students and I study genetic structure in tropical birds and other organisms to address how this diversity evolved and how it continues to evolve as climates change and humans continue to alter landscapes.

We study comparative genetic structure and evolution primarily in the Afrotropics, the Neotropics, and the Asian tropics.  I am an ornithologist, but students working with me and my wife Shannon Hackett and other museum curators also have studied amphibians and small mammals (bats and rodents) and more recently internal, external and blood parasites (e.g., Lutz et al. 2015, Block et al. 2015, Patitucci et al. 2016).  Research in the our lab has involved gathering and interpreting genetic data in both phylogeographic and phylogenetic frameworks. Phylogenetic work on Neotropical birds has focused on rates of diversification and comparative biogeography (Tello and Bates 2007, Pantané et al 2009, Patel et al. 2011, Lutz et al. 2013, Dantas et al. 2015).  Phylogeographic work has sought to understand comparative patterns of divergence at level of population and species across different biomes (Bates et al 2003, Bates et al. 2004, Bowie et al. 2006, I. Caballero dissertation research, Block et al. 2015, Winger and Bates 2015, Lawson et al. 2015).  We also have used genetic data to better understand evolutionary patterns in relation to climate change across landscapes (e.g., Carnaval and Bates 2007) that include the Albertine Rift (through our MacArthur Grants, e.g., Voelker et al. 2010, Engel et al. 2014), the Eastern Arc Mountains (Lawson dissertation research, Lawson et al. 2015), the Philippines (T. Roberts and S. Weyandt dissertation research) and South America, particularly the Amazon (Savit dissertation research, Savit and Bates 2015, Figueiredo et al. 2013), and we are entering into the genomic realm focusing initially on Andean (Winger et al. 2015) and Amazonian birds (through our NSF Dimensions of Diversity grant). Shane DuBay is doing his dissertation research in the Himalayas on physiological plasticity in Tarsiger Bush Robins.  Nick Crouch, who I co-advise at U. Illinois, Chicago with Roberta Mason-Gamer, is studying specialization in birds from a modern phylogenetic perspective.  We seek to create a broader understanding of diversification in the tropics from a comparative biogeographic framework (Silva and Bates 2002, Kahindo et al, 2007, Bates et al. 2008, Antonelli et al. 2009).  João Capurucho (U. Illinois, Chicago, co-advised with Mary Ashley)  is studying phlylogeography of Amazonian white sand specialist birds and Natalia Piland (Committee on Evolutionary Biology, U. Chicago) is studying the impact of urbanization on Neotropical birds.  New graduate student Valentina Gomez Bahamon (U. Illinois, Chicago) is also working Boris Igic and me, after doing her Master Degree in her native Colombia on genomics and the evolution of migrating Fork-tailed Flycatchers (Tyrannus savana).  Jacob Cooper (Committee on Evolutionary Biology, U. Chicago) is studying the diversification of birds in Afromonte forests

Josh Engel and I are working up multi-species phylogeographic studies of birds across the Albertine Rift, based the Bird Division's long term research throughout the region.  We are working up similar data sets for Malawian birds.  Our current NSF Dimensions of Diversity grant on the assembly of the Amazonian biota and our NSF grant to survey birds and their parasites across the southern Amazon are generating genomic data for analysis in collaboration with paleoecologists, climatologists, geologists, and remote sensing experts from the U.S. and Brazil.  These large collaborative projects are providing new perspectives on the history of Amazonia.