The Paleozoic era's Silurian period saw animals and plants finally emerge on land. But first there was a period of biological regrouping following the disastrous climax to the Ordovician.

However, in 2018 two University of Cambridge scientists named their paper The Silurian hypothesis ... "This short time period ...

Learn about the time period that took place 416 to 359 million ... a group that first appeared during the Silurian with powerful jaws lined with bladelike plates that acted as teeth.