● Continents came together to form the supercontinent Pangaea.
● By the end of the period, the reptiles split from a second amniote lineage (which would lead to the mammals).
● Ray-finned fishes became common in fresh waters.
● At end of the Permian, massive volcanic eruptions, ash blocked sunlight, caused climate cooling, resulting in the largest glaciers in Earth’s history.
● O2 dropped to ~12%, most animals unable to survive >500 m ASL. Result: greatest mass extinction in Earth’s history (96% of all spp extinct).