Major episodes of extiction punctuated the long history of life on Earth. The Class Aves participated in several of them, starting in the late Cretaceous. In another episode at the beginning of the Pleistocene epoch about 3 million years ago, climatic changes caused the extiction of at least 25 precent of the existing bird species. (查看原文)
The carbon-isotope signatures of eggs and natal down of the hatchling do not match those of estuaring ecosystems. Instead, they are typical of the Arctic tundra, demonstrating the direct transfer of resources ingested after arrival in the Arctic. (查看原文)
还没人写过短评呢
还没人写过短评呢