Bios Megafauna 2nd EditionStart as a plant or animal making first landfall half a billion years ago, then evolve it on drifting continents in the face of competition and huge ecological events: Win if become the dominant herbivore or carnivore. In the full game you can grow from 200 grams to 20 tonnes. The atmosphere is tracked for oxygen, cloud cover, and greenhouse gases, and the decisions the players make influence the climate.