There have been 5 major extinction events in the history of life on planet earth. Now a study done on Sierra Nevada amphibians, published in the Proceedings of the National Academy of Sciences, found that Sierra Nevada amphibians are in severe danger of extinction and that this may be a sign of things to come - even suggesting that we may be in the midst of the sixth major extinction event. From LA Times Greenspace:
Of the Sierra Nevada's seven amphibian species, five are threatened. Two of these species, the Sierra Nevada yellow-legged frog and the Southern yellow-legged frog, had their populations decline by up to 98% over the last few years, even in highly-protected areas such as Yosemite National Park.
