A History of Mass Extinctions

The video discusses Earth's mass extinction events, starting with the Ordovician Silurian extinction 439 million years ago, caused by sea level changes. The Late Devonian extinction followed, with unknown causes but significant marine life loss. The Permian Triassic extinction, the worst in history, was driven by volcanic eruptions and global warming. The end Triassic extinction had similar causes but was less severe. The Cretaceous Tertiary extinction, possibly worsened by a meteor impact, led to the dinosaurs' demise. Currently, a sixth mass extinction is underway, driven by human activities like pollution and overpopulation. Unlike past events caused by nature, this one is man-made, suggesting humans can also halt it.

What was a significant cause of the Permian-Triassic extinction?

• Meteor impact

• Ice age

• Volcanic eruptions

• Rapid sea level changes

How much marine life was lost during the Late Devonian extinction?

• 70%

• 50%

• 22%

• 95%

Which extinction event is associated with the extinction of the dinosaurs?

• End-Triassic extinction

• Late Devonian extinction

• Cretaceous-Tertiary extinction

• Ordovician-Silurian extinction

What is a common factor between the Permian-Triassic and end-Triassic extinctions?

• Sea level rise

• Global warming

• Ice age

• Meteor impact

What is a major factor contributing to the current sixth mass extinction?

• Natural climate change

• Human activities

• Volcanic eruptions

• Meteor impacts