A change in atmosphere and vegetation forces our terrestrial clades to adapt to life in open habitats. 0:00 - Climate change 2:12 - Brachyphytes 4:32 - Lophostomes 5:19 - Opisthopterans 11:15 - Titanopods 15:24 - Eurycheirids 18:49 - Leptopods 21:41 - Onychodonts