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 were the main factors contributing to the Cretaceous Tertiary extinction?

What human activities are currently contributing to the 6th mass extinction?