Students in BIO105/BIO103 at UWL, in the Pacific Northwest, and in the greater Boston area agreed to allow us to use their data and helped us to refine the test, study design, and lesson plan. UWL Department of Biology graduate assistants were helpful and excited about teaching using this method. UWL Department of Biology work-study students and graduate student Patrick Kelley and UC Santa Barbara graduate student Alice Nguyen were of great help in gathering and organizing the data. Mike Abler, Lee Baines, Eric Strauss, Renee Redman, Anton Sanderfoot, and Rick Gillis helped gather data in their classes. Faye Ellis arranged the administration of the lab. Eric S. J. Harris and Mac Cannady provided useful comments on early drafts of this paper. Two anonymous reviewers provided extensive and constructive comments as well. Many people at SimBio worked on putting together the virtual lab, most prominently Susan Maruca, Derek Stal, Jennifer Wallner, and Steve Allison-Bunnell. We thank Eric Klopfer and his colleagues at the Scheller Teacher Education Program at the Massachusetts Institute of Technology for support of this study and for lab space. The University of Wisconsin Institute for Race and Ethnicity Faculty Diversity Research Grant provided support for K.E.P. This research was funded in part by grant 0717495 from the National Science Foundation (NSF). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the NSF.