All dinosaurs branch off from dinosauria. The two major branches are saurischia and ornithiscia.
The two main branches of saurischia are therapoda and sauropoda.
The three main branches of ornithischia are marginocephalia, thyreophora, and ornithopoda.
An example of a dinosaur belonging to therapoda is velociraptor.
An example of a dinosaur belonging to sauropoda is saltasaurus.
An example of a dinosaur belonging to marginocephalia is einiosaurus
An example of a dinosaur belonging to thyreophora is ankylosaurus
An example of a dinosaur belonging to ornithopoda is parasauralophus
The dinosaurs went extinct because a large volcanic eruption threw ash in the air, and a massive meteor hit Earth
The meteor stirred up lots of dust. That dust blocked out the sun.
Without the sun, plants could not grow. Without plants, plant eating dinosaurs starved.
Without the plant eating dinosaurs, the meat eating dinosaurs died.
That was how the dinosaurs went extinct
Pterosaurs were winged creatures that were not dinosaurs. Pterosaurs went extinct along with dinosaurs. An example of a pterosaur is quetzalcoatlus.
Icthyosaurs were ancient dolphinlike creatures that lived in the ocean. An example of an icthyosaur is shonisaurus.
Mosasuars were predators in the ocean during the time of dinosaurs. An example of a mosasaur is mosasaurus.
Many creatures lived beside the dinosaurs, but most of them went extinct with the dinosaurs.