After 40 years of research on Darwin’s finches, Peter and Rosemary Grant have written their valediction. The People Who Saw Evolution. Philornis downsi (family Muscidae; subfamily Azeliinae; tribe Reinwardtiini) is a semi-haematophagous obligate avian parasite in its three larval stages, whereas adult flies are non-parasitic and feed on organic matter [].Adults lay eggs inside the nares of newly hatched nestlings (usually at one to three days old), which hatch into first instar larvae [17, 24]. In the Galapagos islands, this is exemplified by the introduced guava (Psidium guajava), considered one of the greatest threats to the local biodiversity due to its effective spread in the archipelago and its ability to outcompete endemic species. Darwin’s finches vary in shades and tones, but not enough to make the changes in appearance as obvious as other species of birds. It was thought a species of large tree finches arrived first, and then diverged into a “medium” species and “small” species. The Galapagos Finches are one of the most widely recognized examples of research in evolutionary biology. On a desert island in the heart of the Galapagos archipelago, where Darwin received his first inklings of the theory of evolution, two scientists, Peter and Rosemary Grant, have spent twenty years proving that Darwin did not know the strength of his own theory. Previous studies have demonstrated some of the molecular mechanisms that regulate morphogenesis of the prenasal cartilage, which forms the initial beak skeleton. Starry Night Nudibranch via seaslugforum.net. The 13 species of finches that live in the Galápagos Islands evolved from a single common ancestor within the past 3 million years. Bird beaks display tremendous variation in shape and size, which is closely associated with the exploitation of multiple ecological niches and likely played a key role in the diversification of thousands of avian species. On first glance of a Marine Iguana, your first thoughts would probably be of a primitive dinosaur, with its dorsal crest and primitive features. Based on the adaptations Darwin observed in finches and tortoises in the Galapagos he wonderered if species living on different islands had once been member of the same species Darwin's observation that finches of different species on the Galapagos Islands have similar physical characteristics support the hypothesis that these finches Darwin’s finches, or Galapagos finches, are small land birds found in the Galapagos Islands. Image caption This is an image of the Big Bird lineage, which arose through the breeding of two distinct parent species: G. fortis and G. conirostris . The Galapagos Islands comprise an archipelago of 13 major and about a hundred smaller islands in the Pacific Ocean, off the coast of South America’s Ecuador.It was a study of the biodiversity of the species of these islands that gave rise to the famous scientific theory of evolution through natural selection by Charles Darwin.