The first animals may have appeared during this period according to genetics. Early animals were sponge-like and lived in low-oxygen waters.
850 BC - 550 BC
The First Freeze
A deep freeze occurred that affected all of the Earth.
Warming of Earth
The volcanoes increased the atmospheric carbon dioxide levels enough to warm the earth above freezing levels. The algae levels in the ocean also increased which is evident due to the steranes that have been found.
The Second Freeze
After a period of warmth, the Earth began to freeze again.
635 BC - 542 BC
Ediacaran life was primarily soft bodied marine life that is likely not related to any phyla seen today.
The Earth began warming again. Volcanoes increased the amount of carbon dioxide in the atmosphere and this helped trigger the warming.
This marks the beginning of the Cambrian Explosion which lasted 35 million years. Many extant phyla can be traced back to this time. The climate likely had more oxygen due to plants and algae and was better able to support more complex life.