The Mesozoic era consisted of the Triassic, the Jurassic, and the cretaceous time periods. It lasted about 180 million years, and there are many ideas on how it ended. It is thought that a mass extinction happened during this time where most of the life forms disappeared, especially the dinosaurs. There are also hypotheses that state disease, volcanic eruptions, or even giant impacts hitting the earth could have ended this era. After that came the Cenozoic era in which humans were thought to show up.
