Lots of neutral mutations occur, and they don't get selected in or out. They just persevere in the gene pool. Every now and then, a change in the environment makes such mutations advantageous to have. If they didn't exist, the species might go extinct -- most of them do. But sometimes, some of them may possess just the right characteristics (previously neutral mutations) for continued survival.
Looks like the soft sciences (biology, genetics, etc.) are taking over from the hard sciences (paleontology, geology, etc.).
At least paleontologists, geologists and archaeologists aren't afraid of getting their hands dirty!