Jurassic period
The Jurassic began after the mass extinction event that ended the Triassic. Life, however, was quick to recover from this blow and the Jurassic eventually became host to the most diverse range of organisms that Earth had yet seen. Amongst them were the first birds and some of the dinosaurs. Continental break-up during this time gave rise to the sea that would eventually widen to become the Atlantic Ocean. The ocean floor that formed at this time is the oldest surviving on the planet - all older ones having now been 'recycled' through plate tectonics.
Began: Triassic-Jurassic mass extinction
205 million years ago
205 million years ago
Ended: 142 million years ago