Tue. May 28, 2019 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall8, Makuhari Messe)

convener:Yukio Isozaki(Department of Earth Science and Astronomy, Multi-disciplinary Sciences - General Systems Studies, Graduate School of Arts and Sciences, The University of Tokyo), Yusuke Sawaki(The University of Tokyo)

Phanerozoic biodiversity is the consequence of repeated extinctions and following diversifications in the past, which were caused by large-scale environmental changes, in particular, by extremely rapid and drastic forcing that changed the environments of the biosphere. Irreversible and episodic changes in material cycling on the planet and influences of severe galactic cosmic radiation enhanced by encounter with dark cloud are nominated as major driving mechanisms for the alleged rapid, large-scale environmental perturbations. The biodiversity change in the fossiliferous Phanerozoic record is characterized by 5 major mass extinctions within the long-term trend of diversity increase. Nonetheless, each extinction event has been explained rather in ad hoc manner, without any universal explanation. Therefore, ultimate triggers that caused the Phanerozoic biodiversity still remain as unsolved issues. This session discusses the ancient environmental changes related to Phanerozoic biodiversity under a new light of the recent progress in geology.