When did it occur?
It occurred 543 million years ago and went on for 295 million years.
What was it like back then?
A lot of the land was water back then but that made it better for plants to grow. Animals usually lived near the ocean and hunted for food and drank sea water or puddles from rain.
What animals lived during this time period?
Small dinosaurs, hard shelled mammals, and small sea creatures. Most animals were small during the start of this time. But towards the middle of it bigger animals came along.