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Galápagos Finches: Famous Beaks 5 Activity 122 to collect samples of unknown plants and animals. Darwin captured some of the Galápagos nches for his collection, but at the time, he was more interested in plants and rocks and in the islands’ stranger inhabitants. In his diary he mentioned the “hideous” lizards that gathered seaweed in the ocean and giant tortoises that were big enough to ride on. Years later, however, it was the collection of little nches that puzzled and in- spired him most. Darwin wondered why there were so many species of nches on the Galápagos Islands, and why they were as dierent and as similar as they were. Finches don’t migrate, so the birds he collected must have evolved on the islands. He speculated that the rst birds blew to the Galápagos from the coast of South America, evolving in a dozen directions on dierent islands. Te nches’ beaks gave Darwin a clue about how a species could evolve. Te size and shape of a bird’s beak determine the kinds of food the bird can eat and the kinds it can’t. A slight dierence might give one bird an advantage over another in surviving and reproducing, and the advantaged ospring, in turn, would be more likely than others to survive and reproduce. Darwin called this process natural selection. Others described it as “survival of the ttest.” Darwin thought that natural selection worked too slowly to be seen in one’s lifetime. More than a hundred years after Darwin’s visit, Rosemary and Peter Grant trav- eled to the Galápagos Islands to take a closer look at the nches. Te Grants won- dered: If they took careful measurements of the nches and the foods they ate, would they be able to see the changes that Darwin imagined? Te Grants and their students set up a research camp on Daphne Major, an island in the center of the Galápagos. Daphne Major is a biologist’s dream because Rosemary and Peter Grant study the evolution of nches on the Galápagos Islands. They are professors at Princeton University. Photos courtesy Rosemary and Peter Grant. Copyright © 2006 NSTA. All rights reserved. For more information, go to www.nsta.org/permissions.