Chapter six looks at the Triassic period, which came after a major extinction event that marked the end of the Permian. It took millions of years for the major groups of animals to recover, but when it did, the world would look very different. Gone were the Therapsids that dominated the Permian. In their place were the reptile groups that would give rise to various forms of crocodiles and that most well known of ancient animals, the dinosaurs. Why this happened is still subject to research.