The Jurassic coastline in Dorset, England, is famous for its fossils.
The Jurassic period is a geological time period dating from around 210 million years ago to about 146 million years ago. This was the time when the Earth's original supercontinent, Pangaea, broke up into Laurasia and Gondwana, and the Gulf of Mexico began to open. It was the middle period of the Mesozoic Era, which began with the onset of the Triassic period some 250 million years ago and ended with the close of the Cretaceous about 65 million years ago.
Dinosaurs
Tyrannosaurus rex was a fierce Jurassic predator.
Dinosaurs were the dominant form of life on land during the Jurassic period. The precursors of birds, they had an erect posture, were both herbivorous and carnivorous and occurred in thousands of varieties. Dinosaurs ranged in size between 1 foot and 200 feet, and in weight from between 2lbs. to over 120 tons. Some were two-legged, others four-legged. They reproduced by laying eggs. The Tyrannosaurus rex was a 42-foot long, two-legged carnivore. Dinosaur fossils are found all over the world.
Ichthyosaurs
Dolphins are descended from ichthyosaurs.
These were giant marine reptiles that looked like fish but were more related to dolphins. They grew to about 13 feet in length, though some could grow to about 40 feet. They used fins for stabilization and fed on smaller reptiles, shellfish and squid. Like dolphins, ichthyosaurs gave birth to live young. They began to decrease in the Middle Jurassic period and became extinct before the dinosaurs died out.
Cephalopods
Ammonites are popular cephalopod fossils.
These were the precursors of today's mollusks and squids, and had symmetrical shells. The animal inside the shell fed by capturing prey using its tentacles. They had advanced vision and were the predators at the top of their food chain during the Jurassic period. Ammonites and nautiloids are the best known cephalopods of the Jurassic period.
Cycads
Ferns developed from cycads.
These were seed plants with a crown of leaves. The leaves grew out from a cylindrical trunk. Cycads had male and female genders and could live for 1,000 years. Cycads are still extant and grow in tropical and subtropical environments.
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