From “Brazil’s Islands in the Sky Defy Evolution” (Creation-Evolution Headlines, August 9, 2012), we learn
Isolated table mountains with sheer cliffs in South America should be natural laboratories for evolution. Why aren’t they?
Substantial diversity was the expectation based on the amount of time these creatures are believed to have been isolated. But when they made the “analyses of two mitochondrial gene fragments evolving at different rates,” they were very surprised: “populations of a given species on individual summits are often closely related to those on other summits (e.g., Oreophrynella), or to those from the surrounding uplands (e.g., Tepuihyla).” Many of the differences were less than 1%. “Uncorrected pairwise distances in both genes indicate unexpectedly low genetic divergence — as low as zero — among multiple tepui summit species or populations in five of the six groups (Stefania being the only exception), as well as among some summit species or populations and uplands populations described as distinct species.”
With such a dramatic clash between theory and practice, the scientists went into damage-control mode. No one is going to buy the idea that the frogs and snakes decided to move from one tepui to another. That would mean going down one 1000 meter cliff, crossing a completely different ecosystem at lower elevation, then climbing up another 1000 meters. The scientists looked at other options:
Judt so … just so … just so …