Colonizing bare rock
My guess is, lichens were the first terrestrial forms of life on earth [because they can live on bare rock], and mosses were the second - because they can live on rock too, especially if lichens have already created a little organic matter there.
Moss actually grows pretty aggressively when it's wet, as you can see all the new clumps that are forming. And when it's dry, the moss turns brown and sits there until the rain comes again, and then it greens right up, in a matter of minutes.
Colonizing bare rock
My guess is, lichens were the first terrestrial forms of life on earth [because they can live on bare rock], and mosses were the second - because they can live on rock too, especially if lichens have already created a little organic matter there.
Moss actually grows pretty aggressively when it's wet, as you can see all the new clumps that are forming. And when it's dry, the moss turns brown and sits there until the rain comes again, and then it greens right up, in a matter of minutes.