‘Plants caused end-Ordovician mass extinction’

This 12 May 2020 video says about itself:

How Plants Caused the First Mass Extinction

In the middle of the Cambrian, life on land was about to get a little more crowded. And those newcomers would end up changing the world. The arrival of plants on land would make the world colder, drain much of the oxygen out of the oceans and eventually, it would help cause a massive extinction event.

The first mass die-off on Earth was also one of the deadliest. Scientists continue to piece together the story of what happened. https://t.co/SMjTfMwoBe

— Discover Magazine (@DiscoverMag) January 20, 2021