With a hat tip to Lynn Margulis, a biologist who was not really a Darwinian:
The more we look through a Gaian lens, the more we see that nearly every aspect of our planet has been biologically distorted beyond recognition. Earth’s rocks contain more than 4,000 different minerals (the crystalline molecules that make up rocks). This is a much more varied smorgasbord of mineral types than we have seen on any other world. Geochemists studying the mineral history of Earth have concluded that by far the majority of these would not exist without the presence of life on our planet. So, on Earth’s life altered surface, the very rocks themselves are biological byproducts. A big leap in this mineral diversity occurred after life oxygenated Earth’s atmosphere, leading to a plethora of new oxidized minerals that sprinkled colorful rocks throughout Earth’s sediments. Observed on a distant planet, such vast and varied mineral diversity could be a sign of a living world, so this is a potential biosignature (or Gaiasignature) we can add to the more commonly cited Lovelock criterion of searching for atmospheric gases that have been knocked out of equilibrium by life. In fact, minerals and life seem to have fed off each other going all the way back to the beginning. Evidence has increased that minerals were vital catalysts and physical substrates for the origin of life on Earth. Is it really a huge leap, then, to regard the mineral surface of Earth as part of a global living system, part of the body of Gaia?
David Grinspoon, “Why Most Planets Will Either Be Lush or Dead” at Nautilus
Grinspoon argues that life helping shape Earth means that most planets will either be lush or dead.
Maybe. David, find us one that isn’t dead and we promise to get back to you soon.
Note: Lynn Margulis: “(born March 5, 1938, Chicago, Illinois, U.S.—died November 22, 2011, Amherst, Massachusetts), American biologist whose serial endosymbiotic theory of eukaryotic cell development revolutionized the modern concept of how life arose on Earth.” –Britannica
See also: What becomes of science when the evidence does not matter? (fine-tuning)
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