Putting Nature At The Center
Life may be unique to Earth. Even if single-celled organisms can readily evolve in conditions that exist on millions or billions of other planets, we have no actual evidence that complex, multi-cellular life exists anywhere else in the vastness of space.
Bacteria appeared on our planet roughly 3.7 billion years ago; by 2 billion years ago, the tree of life was branching into what would become a stunning web of creatures, huge and tiny. Plants, animals, and fungi proliferated, formed relationships, and produced ecosystems. The result was a planet full of life, and one whose atmosphere, temperature, chemical composition, and weather are all largely shaped by the side effects of the strategies that organisms use to thrive.