Asano, Katsura2021-03-052021-03-05https://hdl.handle.net/2097/41274This article is an English translation of the following original article written in the Japanese language and published in 2008. Its English translation was completed and posted by the same author in March, 2021. Life on Earth is generally classified into bacteria, archaea, and eukaryotes, but how eukaryotes, including humans, were originated is a mystery. Recent achievements in geobiochemistry and genomic biology have overturned previous thoughts that the eukaryotes are relatively new and instead showed that their origin can be as old as those of bacteria and archaea. Therefore, searching for the origin of eukaryotes must be reconciled with searching for the origin of cells, and a certain scenario emerges when this problem is considered along with Earth’s geological history.en-USThis Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).https://rightsstatements.org/vocab/InC/1.0/Text