The evolutionary process, Galapagos Finches. Darwin’s finches, inhabiting the Galápagos archipelago and Cocos Island, constitute an iconic model for studies of speciation and adaptive evolution. Based on Darwin’s observations, our understanding of evolution explains that a new species arises when the population of the ancestor is divided. Beak Variation in Darwin's Finches: It's in the Genes . Field studies have shown that beaks evolve by natural selection in response to variation in local ecological conditions. Darwin's finches are well known for their remarkable diversity in beak form and function. The medium ground finch (Geospiza fortis) is a species of bird in the family Thraupidae.It is endemic to the Galapagos Islands.Its natural habitats are subtropical or tropical dry forests and subtropical or tropical dry shrubland.One of Darwin's finches, the species was the first which scientists have observed evolving in real-time.. They comprise 14 closely related species that differ in beak shapes and sizes and live on the Gala pagos islands. We posit a new hypothesis: As a consequence of beak evolution, there have been changes in the structure of finch vocal signals. Darwin’s finches are described in every biology textbook as a classic example of evolution in action. The Galápagos finches are probably one of the most well-known examples of evolution and will … And those finches equipped with Swiss army knife beaks. The finches Darwin collected all had different sized beaks due to Evolution and the different islands they lived on.