Does life improve habitability? (Introduction)

by dhw, Wednesday, May 04, 2016, 12:38 (3124 days ago) @ David Turell

DAVID: A very interesting question, because the author points out necessary cycles on Earth that require life to take part: - http://www.scientificamerican.com/article/which-came-first-on-earth-habitability-or-lif... - QUOTE: "Some wonder if previously overlooked mechanisms—including life itself—could broaden the habitable zone well beyond its current definition. Colin Goldblatt, a planetary scientist at the University of Victoria in British Columbia, even argues that life's ability to alter a planet's climate poses a new paradox: A planet's habitability could depend on whether life has already made itself at home there, a situation that would place habitability and life in a baffling chicken-or-egg scenario.” (My bold) - The article is certainly thought-provoking, but I don't see the chicken-and-egg scenario when it comes to the origin of life. Habitability means conditions suitable for life. It may well be that once there is life, it can change conditions in such a way that they will lead to new forms of life and “improve habitability” (which seems to have been the case here on Earth). But can life begin and survive in conditions unsuitable for life? That wouldn't make sense. No baffling chicken and egg scenario for me. Habitability first, then life, then improvement.