For several decades, scientists have been meticulously documenting minute changes in different finch species on the Galapagos Islands, an archipelago that's been referred to as a "natural laboratory for evolution."
How it started: The initial hybridization event happened in 1981 on the Galapagos island of Daphne Major, where evolutionary biologists Peter and Rosemary Grant conducted most of their research. They studied the group so closely that they noticed when a male large cactus finch, native to a different island 65 miles away, arrived on the island and began breeding with a local population.
What happened: Native females didn't recognize the songs of the new hybrid males, so instead of breeding with the local population as expected, the hybrids bred within their population. This paper shows that after just two generations, they stopped breeding with other populations and have remained reproductively isolated ever since.
Taking off: "In most cases, the offspring of cross-species matings are poorly adapted to their environment," writes Rory Galloway for the BBC. But the large size of these hybrids has allowed them to exploit resources the native birds weren't using, so the birds have flourished.
Go deeper: It just so happens that Darwin's personally annotated copy of The Origin of Species is up for auction. The Guardian has the story.
