The Gaian ecosystem, the self-organized system that we know as Earth, came into being with the emergence of the global bacterial community. That bacterial community still is the foundation of this world. It is Gaia. It is the interconnected network of millions of bacterial biofilms, individual bacteria, and symbiogenic, bacterially generated, complex life-forms that lies deep within the crust of the Earth (perhaps by as much as 5 kilometers), covers the entire surface of the planet, and extends at least 50 kilometers above the Earth’s surface. The Earth itself is around 4.5 billion years old but sometime in its first half to one billion years of existence bacterial life emerged.