2005 年 33 巻 3 号 p. 228-232
The symposium “Coevolution of earth and life” held in 30th SSOEL-Japan meeting- ISOLAB’05 is reported. In the symposium, keynote lecture was provided by Prof. J. L. Kirschvink, who reported on the Paleoproterozoic snowball earth hypothesis. He explained the possibility that the climate disaster is triggered by the evolution of oxygenic photosynthesis. Prof. A. Yamagishi reported his recent experimental results of the last common ancestor of all the living organisms, which he named Commonote. His experimental results supported the hypothesis that the common ancestor was hyperthermophilic. Prof. S. Itoh reported the significance of the photosynthesis on the early evolution of life and earth. He proposed that the photosynthetic system has much more variation than recognized earlier. Prof. T. Hashimoto reported on his resent results of the analysis of 22 genes of eukaryotic species. He emphasized that the deep branching of three amitochondriate lineages, Microsporidia, Diplomonadida and Parabasalia are caused by the long-branch attraction, and is misleading. Prof. Y. Isozaki reported the mass extinction events in the Paleozoic. He explained the possible relation of mantle plume and Paleozoic-Mesozoic extinction. These reports illuminated the ever-increasing knowledge in each of earth science and life science, though there are still many unsettled controversial issues. However, every audience have noticed that these two fields of science can’t proceed ignoring the other and that the clearer picture of early history of earth and life is now emerging by the concomitant progress of the two sciences.
