Major events during the Jurassic included the further breakup of the supercontinent Pangaea, the development of subtropical conditions and larger dinosaurs. The earliest bird also took flight during the late Jurassic, and early mammals emerged that would later dominate the Earth.
The Jurassic period was a time when Pangaea's breakup accelerated. Laurasia, which became the northern portion of North America, broke away. The southern half, in the form of Gondwana, dislodged from the continent in the middle of the Jurassic. The eastern part, which included later-day Australia, Madagascar, India and Antarctica, became an independent land mass from the western portion of the future South America and Africa. Oceans formed between the breakages, and mountain formations from the seafloor raised sea levels.
The oceans gave rise to sea animals that included the finned plesiosaurs, rays, sharks and giant crocodiles. On land, arid regions grew different types of vegetation. This allowed large dinosaurs to survive, such as the Brachiosaurus, which stood 52 feet tall and was 82 feet in length. The Diplodocus was another massive herbivore that was 92 feet long. The size of these animals protected them from predators, such as the Allosaurus. The Archaeopteryx was an early bird that may have evolved from a coelurosaurian dinosaur. The mammals of the Jurassic were small, but they came to have a more prominent role on Earth when the dinosaurs became extinct during the late Cretaceous.