Peter and Rosemary Grant dedicated most of their life researching and studying the evolution of finches in the Galápagos. Together they wrote a
book called 40 Years of Evolution where they tracked finch populations over a period of four decades and concluded the causes and consequences
of significant events leading to evolutionary changes in species. The authors used a vast and unparalleled range of ecological, behavioral, and
genetic data–including song recordings, DNA analyses, and feeding and breeding behavior–to measure changes in finch populations on the small
island of Daphne Major in the Galápagos archipelago. They find that natural selection happens repeatedly, that finches hybridize and exchange
genes rarely, and that they compete for scarce food in times of drought, with the remarkable result that the finch populations today differ
significantly in average beak size and shape from those of forty years ago. The authors’ most spectacular discovery is the initiation and
establishment of a new lineage that now behaves as a new species, differing from others in size, song, and other characteristics. The authors
emphasize the immeasurable value of continuous long-term studies of natural populations and of critical opportunities for detecting and
understanding rare but significant events. By following the fates of finches for several generations, 40 Years of Evolution offers unparalleled
insights into ecological and evolutionary changes in natural environments. Peter R. Grant and B. Rosemary Grant are both emeritus professors in
the Department of Ecology and Evolutionary Biology at Princeton University. They are the coauthors of How and Why Species Multiply and
coeditors of In Search of the Causes of Evolution (both Princeton).