When Life Almost Ended: Mass Extinctions Through Time

Earth’s biosphere has seen six mass extinctions, from the Great Dying to the dinosaurs. Learn how extinction events shaped life—and why scientists warn a 6th may be underway today.

01:41 What causes mass extinction events?
02:42 What do many people think led to the extinction of the dinosaurs?
03:52 How did the extinction of the dinosaurs help mammals thrive?
05:11 What is causing the sixth mass extinction event?

Check out this lesson on our website → https://www.oerproject.com/Big-History-Project/Unit-3/Extinction-Events?WT.mc_id=09_00_2025__YTupdate_OER-YT_&WT.tsrc=OERYT

Stay Connected:
- Join the conversation on our community forum: https://community.oerproject.com/?WT.mc_id=08_00_2025__YTupdate_OER-YT_&WT.tsrc=OERYT
- Follow us on social: https://www.instagram.com/oerproject/ https://www.facebook.com/OERProject

About OER Project:
OER Project supports social studies teachers with free, high-quality curriculum, primary sources, and teaching tools.