Jurassic

The Jurassic was the second period of the Mesozoic Era and lasted from about 201 to 145 million years ago. It followed the Triassic Period and came before the Cretaceous Period. During the Jurassic, dinosaurs became more common on land, and many new species appeared. The first known birds developed during this time, and large marine reptiles lived in the oceans.

At the beginning of the Jurassic, the supercontinent Pangaea continued to break apart. This slow movement separated land into two main parts: Laurasia in the north and Gondwana in the south. As the continents shifted, new coastlines formed, creating shallow seas and new habitats. These changes in land and sea helped shape the environments where plants and animals lived.

The Jurassic climate was generally warm and humid. This allowed large forests to grow, made up of conifers, cycads, and tree ferns. These forests supported many plant-eating dinosaurs, which in turn supported the predators that hunted them. Fossils show that plant and animal life spread widely during this period, filling forests, plains, and coastal areas.

Dinosaurs were a major part of Jurassic life. Long-necked plant eaters like sauropods lived in herds and could reach leaves high in trees. Other plant-eaters, such as stegosaurs, had hard plates or spikes for protection. Meat-eating dinosaurs, including early relatives of species like Allosaurus, lived in different environments and may have hunted alone or in groups. The first birds appeared in the late Jurassic, developing feathers and wings from earlier theropod dinosaurs.

In the oceans, life was also diverse. Marine reptiles such as plesiosaurs and ichthyosaurs swam in open waters and hunted fish and other sea animals. Large schools of fish and many kinds of invertebrates lived in the seas. Coral reefs grew in warm areas, forming complex ecosystems similar to modern reefs. Fossils of shells, bones, and teeth help scientists understand how ocean life functioned in the Jurassic.

The Jurassic Period ended around 145 million years ago. It did not end with a major extinction, but many species slowly changed or disappeared as environments continued to shift. The following Cretaceous Period saw even more changes in plant and animal groups. The Jurassic remains an important period for studying how dinosaurs spread and how early birds and marine reptiles developed.