Our two body plans compete for dominance of the first terrestrial ecosystems. 0:00 - Climate 1:17 - Chemophytes 2:10 - Saprotrophs 3:17 - Lophostomes 4:31 - Malacoforms 7:20 - Diplostomes 10:56 - Stenostracans 11:57 - Coleostracans 13:45 - Osteopods 16:24 - Niche partitioning 17:37 - Platydonts 18:30 - Desmostracans 19:35 - Megalobrachids 20:34 - Dromaeopods 21:16 - Elastospondyls 22:47 - Deinognathans