During his visit to the islands, Darwin noted that the unique creatures were similar from island to island, but perfectly adapted to their environments which led him to ponder the origin of the islands' inhabitants.
Among those that struck Darwin so greatly were the finches that are now named in his honor. Darwin would later base some of his thought from the supposing that these finches were all descendents of the same lineage.
Years later in 1859, Darwin finally consolidated all of his observations into his famous book On The Origin of Species, drastically and controversially altering the scientific view on the biological origins of life.