ECOLOGY, SPECIATION, AND ADAPTIVE RADIATION: THE LONG VIEW

Abstract

Review of: How and Why Species Multiply: The Radiation of Darwin's Finches. Peter R. Grant and B. Rosemary Grant, 2007. Princeton University Press, Princeton, New Jersey, xvii + 272 pp. HB $35.00, ISBN 978-0-691-13360-7. We owe a debt of grati tude those who have the foresight and fortitude pursue long term studies, foremost among them Peter Grant and Rosemary Grant. It is unusual enough pursue a research program for years on end, learning from the research subjects what questions ask and dauntlessly pursuing the answers. It is even more impressive when this has required returning the field for 34 years, mostly on the small island of Daphne Minor, a dry, hot, unremittingly windy cinder cone lacking shade, water, even level ground except for a small spot near the crest, where the Grants set their tent and subsisted on supplies unloaded from rowboats on pitching seas (D. Schluter, pers. comm.). Here, together with their and other collaborators, they tracked the life of every individual bird and its descendants. The Grants planned and assiduously carried out an extraordinary array of studies, which they here summarize and weave together in a book written to capture the essentials and the highlights for an intended audience of students (p. xvii). With inspiring acknowledgment that we build on the insights and work of our predecessors, they dedicate the book the memory of David Lack, who doubtless would have been deeply satisfied see some of his conclusions supported and other explorations he probably could not have imagined. This book is at once a compact summary of the Grants' re search and a fine teaching tool, as they intended: it is an ideal study, for undergraduate or graduate student alike, of how evolutionary and hypotheses can be tested by observation and ex periment, of how initial questions lead deeper questions still, of how diverse strands of information and theory?from geologi cal and phylogenetic history genetics, development, population ecology and behavior?can and must be woven into a tapestry of explanation, and how questions and further research yet remain even after so long and comprehensive effort. It is also, for those mo e widely read, a portrait of a stage in the history of a question in evolutionary biology and its attempted answer. As recently as 15 years ago, few people seem have realized that there ex isted almost no strong evidence that speciation?the evolution of reproductive isolation?is caused by divergent selec tion, even though this hypothesis was widely held. Since then, ecological (Rundle and Nosil 2005) has come center stage in speciation studies and has acquired considerable evi ence (Schluter 2000; Funk et al. 2006; Funk and Nosil 2008). Among the most prominent leaders of this movement have been the Grants and their (see Schluter 2000; Price 2008), and their students' in turn (e.g., Rundle 2002). Some of the e rliest and perhaps most influential evidence of spe ciation came from the Grants' studies of Darwin's finches. As I