Islands and Evolution

Back in middle shool I remember we had an assignment where we had to go to the school library, find a biography, and write a book report about it. I chose a biography about Charles Darwin. I remember learning about Darwin's Finches. Onboard the HMS Beagle, he was meant to be the geologist on board. Related to the field, however, was his interest in the geographical distribution of species. He collected some bird samples, thinking they were unrelated species of birds, and brought them back for study. His bird nerd scientist buddies back home later revealed to him that they were all closely related to the same species of finch. Much later, through genetic testing, we learned that Darwin's finches actually belong to the Tanager family, though their common names still identify them as Finches. Birds are unique in that they can fly to an island that is otherwise cut off for other wildlife back at the mainland. For birds that happen across the island, they'll find vast niches of resources at their disposal with very little competition. This is an example of Adaptive Radiation. Due to the unique isolation provided by islands, many living varieties of a few lucky migrants can flourish and survive near enough to each other and for long enough for humans to notice. This became a key piece of evidence for Charle's Darwin's book On the Origin of Species. It introduced the concepts of evolution through natural selection to a wider audience and was a major catalyst in the development of the field of Evolutionary Biology. This post was inspired by reading this article Why Evolution Goes Wild On Islands: The Science Of Adaptive Radiation . From that article I learned about two other Islands where Adaptive Radiation took place. The Vangas of Madagascar, where a woodpecker evolved from a warbler; and the Honeycreepers in Hawaii where over 50 different honeycreeper species evolved from a common ancestor. Here is a house finch I snapped a picture of in my back yard. It's probably not very closely related to the finches on the Galapogos, but we're talking about finches so why not?