An important look at a groundbreaking forty-year study of Darwin's
finches
Renowned evolutionary biologists Peter and Rosemary Grant have produced
landmark studies of the Galápagos finches first made famous by Charles
Darwin. In How and Why Species Multiply, they offered a complete
evolutionary history of Darwin's finches since their origin almost three
million years ago. Now, in their richly illustrated new book, 40 Years
of Evolution, the authors turn their attention to events taking place
on a contemporary scale. By continuously tracking finch populations over
a period of four decades, they uncover 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.
