20,000,000 years ago, hardly any time at all on the Universe scale, began the Devonian extinctions, up to seven events spread over 10 million years, 50% of life was exterminated. The subject to be covered in some detail soon.
65,000,000 The 170 million year period of the dinosaurs ends. Everest-size asteroid hits Mexico at 70,000 kilometres perhour. 180 kilometre wide crater 75% of species extinct including the dinosaurs. (The K-Pg extinction)
117 Triassic extinction (probable volcanic creating climate change). Crocodiles (dinosaurs) and 60% of amphibians survive. Jurassic period begins.