Peter and Rosemary Grant are well known for How and Why Species Multiply, an evolutionary history of the Galapagos finches first studied by Charles Darwin. Now, in this richly illustrated new work, 40 Years of Evolution, they explore contemporary events, tracking the finch populations over four decades, and reveal the causes and consequences of events that lead to evolutionary change. The authors measure the changes on Daphne Major, one of the smaller islands of the Galapagos archipelago using massive amounts of data which include song recordings, DNA analyses and feeding and breeding behaviour. Their discoveries show that the finches rarely hybridize and exchange genes and how the competition for food in times of drought results in populations that differ significantly in beak size and shape from those of forty years ago. They even discover a new lineage which behaves as a new species, differing in size, song and other characteristics.
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.