The Permian Period
When was it?
286 to 245 million years ago.
What was going on?
Therapsids, aka "mammal-like reptiles", appear. Pangaea begins to form.
A really big mass extinction at the end of the Period.
What were the continents like?
Godwanaland and the equatorial continents continue to move together to form what will become
Pangaea.
What kind of life existed?
The big change from the Carboniferous is the evolution of mammal-like reptiles, which are
probably our ancestors; also, true reptile and insect species continue to evolve and diversify.
Then, at the end of the Permian, a really big mass extinction -- often thought to be the
biggest ever -- hits, wiping out many of the new land vertebrates, as well as a great
diversity of marine life.