Lichens and other things, on wood.

“It is easy to overlook this thought that life just is. As humans we are inclined to feel that life must have a point. We have plans and aspirations and desires. We want to take constant advantage of the intoxicating existence we've been endowed with. But what's life to a lichen? Yet its impulse to exist, to be , is every bit as strong as ours-arguably even stronger. If I were told that I had to spend decades being a furry growth on a rock in the woods, I believe I would lose the will to go on. Lichens don't. Like virtually all living things, they will suffer any hardship, endure any insult, for a moment's additions existence. Life, in short just wants to be.” 

― Bill Bryson, A Short History of Nearly Everything