Why does everybody agree that atmospheric oxygen... comes from life, but no one speaks about the other gases coming from life? - Lynn Margulis

The fundamental division of forms of life on Earth is not that between plants and animals, as is commonly assumed, but between prokaryotes—organisms composed of cells with no nucleus, that is, bacteria—and eukaryotes—all other life forms.

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.

There is little doubt that the planetary patina—including ourselves—is autopoietic. Life at the surface of the Earth seems to regulate itself in the face of external perturbation, and does so without regard for the individuals and species that compose it. More than 99.99 percent of the species that have ever existed have become extinct, but the planetary patina, with its army of cells, have continued for more than three billion years. ...trillions of communicating, evolving microbes. The visible world is a late-arriving, overgrown portion of the microcosm, and it functions only because of its well-developed connection with the microcosm's activities.