The Mesozoic era was a time 248 million to 65 million years ago. It is called “The Age of the Reptiles.” The Mesozoic was separated into three sections, the Triassic Period, the Jurassic Period, and the Cretaceous Period. The Jurassic period stretched from 206-144 million years ago. During that time, seasons were mild, the sea level was very high, and there was no more polar ice.
Date of the Jurassic Era:
206-144 million years ago
The Beginning:
This era had global changes in continental arrangements, oceanographic patterns, and biological systems. During this era, Pangea split apart, letting the development of the central Atlantic Ocean and the Gulf of Mexico. Because of this, it led to volcanic activity, mountain-building events, and the attachment of islands onto some continents. Seaways covered a lot of continents, and marine sediments were deposited, which preserved a variety of fossils.
Landforms:
There were mountains, volcanoes, oceans, rivers, and plateaus during the Jurassic Era. But, the Jurassic period also had tons of desserts. There were also forests in which the dinosaurs lived in. This era was filled with much greenery, wildlife, and desserts.
Climate:
Oxygen found in ocean fossils suggests that Jurassic temperatures were warm. Chemical evidence suggests that shallow waters in the low latitudes were around 20 °C or 68 °F. Deep waters, however, were about 17 °C (63 °F). The cool temperatures existed during the Middle Jurassic and warm temperatures in the Late Jurassic. Earth's climate changed quickly from hot and dry to humid and subtropical.
Scientists have suggested that the sudden increase in volcanic and seafloor-spreading activity during the Jurassic era, released amounts of carbon dioxide and led to higher global temperatures. There is no evidence of polar ice caps in the Jurassic, and this might be caused by the lack of a continental landmass in generally warm conditions.
Life Forms:
In the ocean, life on the seafloor became more complex with an alarming increase of mollusks and coral reef builders by the Middle Jurassic period. Modern fishes became common in Jurassic seas, and they shared the waters with ammonites and other organisms, but they are all extinct today.
On land, an interesting set of plants and animals was dominant by the Early Jurassic. Gymnosperms, also known as naked-seed plants, replaced the seed ferns that dominated older ecosystems. Dinosaurs and mammals replaced the early reptiles and mammal groups found in Late Triassic times. Bird fossils were found in Jurassic rocks, however, groups of birds now living were present in Jurassic terrestrial ecosystems. The communities would have been very different because dinosaurs were the dominant animals.
Reptiles have overcome the growing difficulties of support and look-alikes that limited amphibians. They also have strong body tissue skeletons supported by advanced muscular systems for body support and movement. Some reptiles in the Jurassic Era were large marine carnivores named Plesiosaurs. These reptiles normally had broad bodies and long necks with four flipper-shaped limbs. On the other hand, Ichthyosaurs was a more fish-shaped reptile that was common in the early Jurassic Period.
