The  given figure shows finches (with variety of beaks), which Darwin found in Galapagos Islands. The ancestors of these different species of finches were

Darwin's finches show a variety of beaks suited for eating large seeds, insects and fruits, cactus, worms, etc. Ancestral stock of Darwin's finches were seed-eating and they radiated out from South America mainland to different geographical areas of the Galapagos Islands, where they found competitor-free new habitats.