Zhe-Xi Luo, Douglas H. Erwin, Samuel A. Bowring, Jin Yugan, and Xiangdong Wang
The history of earth and its diverse life are characterized by several critical transitions. These include the origins of metazoan animal phyla during the Neoproterozoic, the great biotic extinction and subsequent recovery through the Permo-Triassic transition, the Mesozoic origins of flower plants and living vertebrate lineages, and the radiation of mammals in the early Cenozoic. A critical issue in understanding these transitions is the relative importance of ecological processes and response to changes in physical environment. Over the past decade important discoveries and research advances for understanding these great evolutionary transitions have come from China and the United States, the two countries with remarkable scientific resources and complementary strength in geological and paleontological research.