I Contain Multitudes: The Microbes Within Us and a Grander View of Life

by Ed Yong

For roughly the first 2.5 billion years of life on Earth, bacteria and archaea charted largely separate evolutionary courses. Then, on one fateful occasion, a bacterium somehow merged with an archaeon, losing its free-living existence and becoming entrapped forever within its new host. That is how many scientists believe eukaryotes came to be. It’s our creation story: two great domains of life merging to create a third, in the greatest symbiosis of all time.

microbes, every host is effectively an island – a world surrounded by void.