“Life on earth writ large, the grand network of life, is a greater and more dynamic terraforming engine than any person could ever conceive. It has been operating ceaselessly for several billions of years…On what type of timeframe were you imagining that the shoebox of lichen you send to Mars was going to transform Frozen Airless Radioactive Desert Hell into a place where people could grow wheat?”
https://defector.com/neither-elon-musk-nor-anybody-else-will-ever-colonize-mars