Evolution Unit StudyLesson 7: We learned about the asteroid impact which ended the Cretaceous Period.
Scientists divide historic time into three eras; Paleozoic, Mesozic and Cenozic. Each era is further divided into periods. At the end of each era and period extinct events wiped out life. The extinction events which occurred at the end of each era were much more devastating to existing life. After each extinction event new and different life forms were allowed flourish.
The first major extinction event began with a complete freeze of the Earth and happened at the beginning of the Paleozoic Era. The second mass extinction event occurred between the Paleozoic and Mesozic Eras and was brought on by a massive volcanic eruption in Sibera. The final mass extinction event was caused by an asteroid impact at the end of the Mesozic Era.
Today it is widely accepted that 65 million years ago an asteroid struck our planet and wiped out most life on Earth including the dinosaurs. The video below tells the story.