evolution of dinosaurs through four of the periods in which they lived and evloved. I started with Dimetrodon, a lizard in in the early Permian period, which the dinosaurs evolved from. Then I used Asilisaurus from the Triassic period. I then used Brachiosaurus from the Jurassic Period. Then I used tyrannosaurus Rex from the Cretaceous Period. Then just for fun I put in an asteroid.