association mapping, will allow the identification of the genes underlying traits such as these.

Adaptive radiations continue to offer a rich resource for understanding the process of evolution. As we have outlined here, they are ideal for identifying general evolutionary trends and often consist of the repeated evolution of the same traits, allowing tests of whether evolution follows predictable trajectories. As we move forward in an era when genomic resources will be increasingly available, adaptive radiations offer additional advantages. Because recent rapid radiations have resulted in closely related taxa with distinct adaptive features, the genomes are likely to be remarkably similar overall, thus leaving relatively clear signals of which genes are likely involved with speciation and adaptation [e.g., Turner et al. (2005)]. Furthermore, the development of genomic tools for 1 species will likely be transferable to other taxa in an adaptive radiation (Abzhanov et al., 2008). Exploration of phenotypes in the field and their genetic basis provides a powerful approach for describing evolutionary processes that have shaped biodiversity. For the reasons outlined above, adaptive radiations maximize our ability to detect patterns and test both long-standing and emerging hypotheses about the nature of adaptive evolutionary change.

We thank John Avise and Francisco Ayala for the opportunity to discuss our work at the Sackler Colloquium and John Avise, Dolph Schluter, and an anonymous referee for providing comments that greatly improved the manuscript. This work was supported by National Science Foundation Grant EF-0412727.