新托福听写训练 第6期（在线收听）

Nature often sends signals indicating what is going to do. Some of these signals are pretty obvious others not so much. Smoke beginning to pour some out of volcano probably means that it will erupt sometime soon. Less obvious and easily overlooked is the fur of the woolly worm. It's been claimed that you can make a long range weather forecast based on the thickness of woolly worm's fur. The thicker the fur, the harsher the winter is predicted to be. The thinking of course is that the worm know what they have to prepare for in order to survive. However, I don't know of any research on this. I want to share with you something biologists have noticed in the last few years. Amphibians, especially frogs have been disappearing in alarming numbers. In places where a couple of years ago there were populations, now there are none. Surly nature is urgently signaling something. But what? What makes this particularly worrisome is the fact that the phenomenon isn't restricted to any specific climate, altitude, country. There is no common link. No one element that scientists can point to and blame. It'll be easy to say the global warming or loss habitat due to the over population. But these don't begin explain the scope of the problem. Amphibians evolved involved around 350 million years ago, which means they came long before the dinosaurs. They have endured phenomenon change in the earth, all of which add to the mystery in concerns. Why was the population that such ancient older animals change so suddenly after that much time?