The First Hypothesis: Darwin’s Finches
Darwin (1835; Galápagos): Diversity in structure in one small, intimately related group of birds (…) one species has been modified for different ends”
Beak size and shape correspond to primary food ? natural selection
Supporting evidence: 1970’s - dry year ? tender seeds rare ? birds must resort to larger, dry seeds ? larger beak birds show higher survival rate (increase in beak size) beak size inherited ? genetic variation