Evolution does not always lead to more advanced species. Evolution is simply a description of the way change occurs in biological creatures over many generations in order to better exploit a certain environment. Evolution sometimes leads to progress, but it sometimes leads in the opposite direction. For instance, the Texas blind salamander has lost his eyes after many generations of evolution due to the uselessness of eyes in the dark caves where he dwells. As reported by biologist David M. Hillis, these salamanders have successfully adapted to their environment by loosing their eyes. But going blind does not seem to be much in the way of progress from a global perspective.