When Rosemary and Peter Grant first defined foot on Daphne Major, a tiny island in the Galpagos archipelago, in 1973, they had no idea it would become a second home. The husband and wife squad , now emeritus biology profs at Princeton University, were looking for a pristine surrounding in which to study evolution. They hoped that the various species of finches on the island would offer the perfect means for uncovering the factors that drive the formation of new species.
The diminutive island wasnt a particularly hospitable place for the Awards to expend their wintertimes. At less than one-hundredth the size of Manhattan, Daphne resembles the tip of a volcano rising from the sea. Guests must leap off the barge onto the edge of a steep ring of land that surrounds a central crater. The islands vegetation is sparse. Herbs, cactus shrubs and low trees provide food for finchessmall, medium and large ground finches, as well as cactus finchesand other birds. The Grant brought with them all the food and water they would need and cooked snacks in a shallow cave sheltered by a tarp from the baking sunshine. They camped on Daphnes one tiny flat spot, scarcely larger than a picnic table.
Though lacking in creature comforts, Daphne proved to be a fruitful alternative. The Galpagos extreme climateswinging between periods of severe drought and bountiful rainfurnished ample natural selection. Rainfall differed from a meter of rainfall in 1983 to none in 1985. A severe drought in 1977 killed off many of Daphnes finches, setting the stage for the Grants first major discovery. During the dry spell, big seeds became more plentiful than small ones. Birds with bigger noses were more successful at cracking the large seeds. As a outcome, big finches and their progeny triumphed during the drought, triggering a lasting increase in the birds average sizing. The Grant had observed evolution in action.
That striking detecting launched a prolific career for the pair. They visited Daphne for several months each year from 1973 to 2012, sometimes bringing their daughters. Over the course of their four-decade tenure, the couple tagged approximately 20,000 birds spanning at the least eight generations .( The longest-lived bird on the Grants watch survived a whopping 17 years .) They tracked almost every mating and its progeny, attaining big, multigenerational pedigrees for different finch species. They took blood samples and recorded the finches sings, which allowed them to track genetics and other factors long after the birds themselves succumbed. They have confirmed some of Darwins most basic predictions and have earned a variety of prestigious science awardings, including the Kyoto Prize in 2009.