How does life colonize a desolate environment for the first time?
Let’s say a volcano erupts and wipes out all life on an island. Is this island destined for desolation? Fortunately not, thanks to “pioneer species” who colonize bare earth after a disturbance, or when the environment is too harsh to allow for colonization by other species.
Pioneer species are usually hearty plants and lichens with few soil requirements. They typically travel by sea or by air with wind-blown seeds (or spores) that serendipitously land on virgin land. They enjoy the competition-free environment, produce their own food through photosynthesis, and if successful, bootstrap a new ecosystem.