<humour> I belong to the group of 400! </humour> If we look at WP [0] there were way more than five extinctions in the past, but each extinction is preceded by

<humour> I belong to the group of 400! </humour> If we look at WP [0] there were way more than five extinctions in the past, but each extinction is preceded by an explosion of new life forms, and that is what define many "geologic periods": * Great Oxygenation Event: Multicellular life forms emerge. * End-Ediacaran extinction led to the Cambrian explosion: Animal phyla appears * Cambrian–Ordovician extinction event led to the Great Ordovician Biodiversification Event: Pelagic life forms colonize reefs and shallow waters. * Ordovician–Silurian extinction events led to Silurian period which saw multi-cellular life moving to earth, not only on sea. On sea, fishes and sharks were now thriving. * Plants thrived in Devonian after most Silurian life disappeared in another "extinction". * etc, etc [0] https://en.wikipedia.org/wiki/Extinction_event#List_of_extinction_events https://en.wikipedia.org/wiki/Extinction_event#List_of_extin... (edited)