I have my optimistic side. Humans are only the second most destructive species in history -- the first being the one that discovered photosynthesis, harnessed the power of the sun, and farted so much oxygen that it flipped the atmosphere from reducing to oxidizing. And almost everything else died.

So I'm looking around the current mass extinction for what's doing well. Jellyfish, for instance, including box jellyfish and men'o'war, are thriving in warm waters where fish struggle to survive. And they're communal organisms; if the singleton biosphere really crashes, they might just take over. I'm also keeping an eye on carnivorous plants because they've already figured out both survival in harsh conditions and movement; they just need to realize they could move around to avoid hazards or seek resources.