What did the grants study what did they observe?

The Grants study, conducted in the 1950s and 1960s on the island of Daphne Major in the Galápagos, focused on the evolution of finch populations. Researchers observed how environmental changes, particularly variations in food availability due to droughts, affected the beak size and shape of finches over generations. They documented rapid evolutionary changes, demonstrating natural selection in action, as birds with beak sizes better suited for available food sources had higher survival and reproductive success. This research provided crucial evidence for Darwin's theory of evolution by natural selection.