Japan Geoscience Union Meeting 2018

Presentation information

[JJ] Oral

B (Biogeosciences) » B-PT Paleontology

[B-PT06] Biotic History

Sun. May 20, 2018 9:00 AM - 10:30 AM 101 (1F International Conference Hall, Makuhari Messe)

convener:Isao Motoyama(Department of Earth and Environmental Sciences, Yamagata University), Takao Ubukata(Division of Geology & Mineralogy, Department of Earth & Planetary Sciences, Kyoto University), Kazuyoshi Moriya(早稲田大学 教育・総合科学学術院 地球科学専修), Chairperson:Motoyama Isao, Ubukata Takao, Moriya Kazuyoshi

9:00 AM - 9:15 AM

[BPT06-01] three-step evolution of primordial life

*Shigenori Maruyama1 (1.Earth-Life Science Institute, Tokyo Institute of Technology)

Keywords:origin of life, birth of life, primordial life

It is assumed that the environmental changes of the Hadean Earth drove a series of prebiotic chemical evolution to emerge first life, which should have been a passive response of primitive life to the forcing effects of environmental change. This concept is consistent with Charles Darwin’s idea explaining “no environmental change, no evolution of life”. This leads us to propose a three-step model for life’s emergence, based on perspectives derived from Hadean geological history.

First, proto-life appears underground as ectosymbiotic biofilms, facilitated by high-energy aqueous electrons from a natural nuclear reactor. Second, proto-life evolves by utilizing solar energy to survive on Earth’s Hadean surface in lacustrine environments. Finally, third proto-life, which is the first life on the Earth, emerges after struggling against the effects of a toxic Hadean ocean.

These stepwise evolution was the result of environmental changes through time. First proto-life born underground could survive with abundant energy from a natural nuclear reactor, however, they need to fit to the Hadean surface environment through splashing of nuclear geyser, resulted in the evolution to second proto-life. Finally, second proto-life encounter the toxic ocean as a result of function of plate tectonics, then first prokaryote was born. Thus, the birth and evolution of life is a response against these environmental changes, and life’s evolution is closely interlinked with the environment.