Peter and Rosemary Grant conducted a 25 year study of the medium ground finch on Daphne Major Island in the Galapagos. They observed and recorded data that clearly showed a shift in the average population beak size to a shorter beak size being more prominent after periods of severe droughts occurring from 1976-1978 and again in
1981-1982. This example of the change in beak depth demonstrates -

Group of answer choices

directional natural selection.

that evolution occurs so slowly that it is not possible to determine if the change has happened in less than a million years.

the environment in the Galapagos Islands has always favored bigger and bigger beaks in the medium ground finch.

disruptive natural selection.