~540 Mya rapid diversification of most animal phyla. Causes debated: O2 rise, Hox-gene innovation, predation. Burgess Shale + Chengjiang fossil records.
~540 Mya rapid diversification of most animal phyla. Causes debated: O2 rise, Hox-gene innovation, predation. Burgess Shale + Chengjiang fossil records.