What did Peter and Rosemary grnt notice in the galapigos islands?

Peter and Rosemary Grant are evolutionary biologists who have studied Darwin's finches on the Galápagos Islands since the 1970s. Their research has provided some of the most important evidence for natural selection acting on a contemporary timescale.

One of the most significant things that the Grants noticed in the Galápagos Islands was the variation in beak size among the different species of finches. They found that the finches with longer beaks were better able to crack open large seeds, while the finches with shorter beaks were better able to eat small seeds. This variation in beak size was due to natural selection, which favored the finches with the most advantageous beaks for their particular environment.

The Grants also noticed that that beak size of medium ground finches (Geospiza fortis) on Daphne Major changed between 1977 and 1982 following a severe drought. With few small seeds left because of the drying drought conditions, finches with larger beaks, better at crushing larger, harder seeds survived and left more offsprings. The average beak size and therefore their fitness increased. By observing populations over years rather than the span of evolutionary history the Grants provided real-time data of evolution taking place before observers' eyes.