Popular Science: Lots of amphibians (a third to a half of all species) are dying, and their deaths are the breaking-edge of what many scientists are calling the first mass extinction since the dinosaurs checked out 65 million years ago, researchers say in a new paper published online in the Journal Proceedings of the National Academy of Sciences. Scientists are not sure when this extinction crisis began–it could have started 10,000 years ago, or during the industrial revolution, or this century. But …