The oxygen crisis that began only two billion years ago prompted the evolution of respiring bacteria. These microbes that used oxygen to derive bioch… - Lynn Margulis

Identity is not an object; it is a process with addresses for all the different directions and dimensions in which it moves, and so it cannot so easily be fixed with a single number.

Life is bacterial and those organisms that are not bacteria have evolved from organisms that were. ...Gene exchanges were indispensable to those that would rid themselves of environmental toxins. ...Replicating gene-carrying plasmids owned by the biosphere at large, when borrowed and returned by bacterial metabolic geniuses, alleviated most local environmental dangers, provided said plasmids could temporarily be incorporated into the cells of the threatened bacteria. The tiny bodies of the planetary patina spread to every reach, all microbes reproducing too rapidly for all offspring to survive in any finite universe. Undercover and unwitnessed, life back then was the prodigious progeny of bacteria. It still is.

The question "What is Life?" is... a linguistic trap. To answer according to the rules of grammar, we must supply a noun, a thing. But life on Earth is more like a verb. It repairs, maintains, re-creates, and outdoes itself.