Figure 43.8: Intra- and Interspecific Competition Influence the Morphology of Coexisting Species In the Galápagos archipelago, seed-eating finches (Geospiza spp.) use their beaks to crack open seeds, which are often in short supply. Individuals with big beaks can crack large, hard seeds that individuals with small beaks cannot eat, whereas small-beaked birds gain more fitness than do large-beaked birds from eating small, soft seeds. Dolph Schluter and Peter Grant documented how the islands differed both in their seed resources and in the morphology of Geospiza species present.a