Answer:
Dramatic reduction in population due to drought in the Galapagos Islands would have prevented the evolution of the many different species of finches.
Step-by-step explanation:
Darwin observed that the shape of beak varies among the finch species. He suggested the ancestral species of finch might have overcrowded the island as a result of competition groups of finches adapted to feed over different food sources.
As a result of the natural selection, the traits for survival were passed down in the generation. However, if the population was reduced due to drought this evolution can be prevented.