The last period of the Paleozoic Era was called the Permian Period. It ended with the Permian-Triassic extinction event, also known as the Great Dying, which was the most severe mass extinction event in Earth's history. It resulted in the extinction of around 96% of marine species and 70% of terrestrial vertebrate species. The exact cause of this event is still debated, but it is believed to be due to a combination of volcanic activity, climate change, and an asteroid impact.
