Notes:
We thank Frank Zok, J. Herbert Waite, Shane Anderson, Nemil Vora, Corey Hardin, Amy Butros, and Armand Kuris for helpful suggestions. DK and NV were supported by a University of California, Riverside Undergraduate Research Grant (#A01009-07431-40-43). JCW and DEM were supported by grants from NASA (NAG1-01-003 and NCC-1-02037); the Institute for Collaborative Biotechnologies, Army Research Office (DAAD19-03D-0004); the NOAA National Sea Grant College Program, U.S. Department of Commerce (NA36RG0537, Project R=MP-92); and the MRSEC Program of the National Science Foundation (DMR-00-8034). PF acknowledges support by the Max Planck Research Award from the Alexander von Humboldt Foundation. BFC acknowledges support from the U.S. National Science Foundation (grant CBET-0829182).