• evolution, phylogenetics, comparative methods

My research focuses on developing new comparative methods and applying them to large phylogenetic datasets. Ongoing progress in building the tree of life provides a rare opportunity to learn about the dynamics of diversification through time and across clades. Current projects in my lab are focused on testing hypotheses about trait evolution, diversification, and adaptive radiation using statitical comparative methods. I am also interested in the interface between quantitative genetics and comparative methods.

• Des Roches, S., J. M. Robertson, L. J. Harmon, and E. B. Rosenblum. In press. Ecological release in white sands lizards. Ecology and Evolution.
• Slater, G. J., L. J. Harmon, P. Joyce, L J. Revell, and M. E. Alfaro. In press. Using Approximate Bayesian Computation to fit models of continuous trait evolution and lineage diversification to incompletely resolved phylogenetic trees. Evolution.
• Eastman, J. M., L. J. Harmon, H.-J. La, P. Joyce, and L. J. Forney. In press. The onion model, a simple neutral model for the evolution of diversity in bacterial biofilms. J. Evol. Biol.
• Eastman, J. M., M. E. Alfaro, P. Joyce, A. L. Hipp, and L. J. Harmon. In press. AUTEUR: A novel comparative method for modeling shifts in the rate of character evolution on trees. Evolution.
• Stack, J., L. J. Harmon, and B. O’Meara. In press. RBrownie: An R package for testing hypotheses about rates of evolutionary change. Methods in Ecology and Evolution.
• Davies, T. J., G. Smith, D. U. Bellstedt, J. Boatwright, B. Bytebier, R. Cowling, F. Forest, L. J. Harmon, A. M. Muasya, B. D. Schrire, Y. Steenkamp, M. van de Bank, and V. Savolainen. 2011. Extinction risk and diversification are linked in a plant biodiversity hotspot. PLoS Biology 9: e1000620.
• Smith, K. L.†, L. J. Harmon, L. Shoo†, and J. Melville. 2011. Evidence of constrained phenotypic evolution in a cryptic species complex of agamid lizards. Evolution 65: 976-992.
• Brock, C. D. †, L. J. Harmon, and M. E. Alfaro. 2011. Testing for Temporal Variation in Diversification Rates When Sampling is Incomplete and Nonrandom. Systematic Biology 60: 410-419.
• Carlson, B. A., S. M. Hasan, M. Hollmann, D. B. Miller, L. J. Harmon, and M. E. Arnegard. 2011. Brain evolution triggers explosive diversification of species and signals. Science 332: 583-586.
• Rosenblum, E. B. and L. J. Harmon. 2011. Same same but different: replicated ecological speciation at White Sands. Evolution 65: 946-960.

• Arnegard, M. E., P. B. McIntyre, L. J. Harmon, M. L. Zelditch, W. G. R. Crampton, J. K. Davis, J.  P. Sullivan, S. Lavoué, and C. D. Hopkins. 2010. Sexual signal evolution outpaces ecological divergence during electric fish species radiation. American Naturalist 176:335-356.

• Yoder, J. B.†, S. Des Roches†, J. M. Eastman†, L. Gentry†, W. K. W. Godsoe, T. Hagey†, D. Jochimsen†, B. P. Oswald†, J. Robertson, B. A. J. Sarver†, J. J. Schenk†, S. F. Spear†, and L. J. Harmon. 2010. Ecological opportunity and the origin of adaptive radiations. Journal of Evolutionary Biology 23: 1581-1596, doi:10.1111/j.1420-9101.2010.02029.x.

• Harmon, L. J., J. B. Losos, J. Davies, R. G. Gillespie, J. L. Gittleman, W. B. Jennings, K. Kozak, M. A. McPeek, F. Moreno-Roark†, T. J. Near, A. Purvis, R. E. Ricklefs, D. Schluter, J. A. Schulte II, O. Seehausen, B. Sidlauskas, O. Torres-Carvajal†, J. T. Weir†, & A. Ø. Mooers. 2010. Early bursts of body size and shape evolution are rare in comparative data. Evolution 64: 2385-2396.  doi:10.1111/j.1558-5646.2010.01025.x.

• Adaptive radiation:
  We are investigating repeated and predictable patterns of speciation and trait change across clades of diversifying species. If adaptive radiations are driven by divergent natural selection following entry into new adaptive zones, then diversification during such radiations may be both repeatable and predictable. We test these hypotheses using natural experiments of lizards, mammals, fish, plants, and other organisms.
• Comparative methods:
  We are developing new comparative approaches to answer ecological and evolutionary questions about the tempo and mode of diversification. The statistical techniques that I have developed in my work are now implemented in a software package, Geiger, written in the R language.
• “Reading” the Tree of Life: 
  We are searching for the signature of diversification and species interactions across broad sections of the tree of life. First, we are working to combine both paleontological data (fossils) and phylogenetic data together to fit models of diversification through time. Second, we have implemented more advanced statistical approaches that can more flexibly fit a wider range of models to data, including models that capture the dynamics of species’ interactions. These new approaches amay help us understand the processes that cause new species to form on the Earth.