TIMELINE DINOSAURIOS

Mesozoic

Cretaceous

Triassic

Jurassic

145-66 M.Y.A

252-201 M.Y.A

201-145 M.Y.A

TRIASIC 252-201 M.Y.A

The Triassic Period is a geological time period that occurred approximately 252 to 201 million years ago. It's part of the Mesozoic Era that follows the Permian Period. The Triassic Period is known for significant changes in Earth's flora and fauna following the mass extinction event at the end of the Permian. During the Triassic, the supercontinent Pangaea continued to exist, with a relatively dry and hot climate prevailing globally. The landmasses were dominated by vast deserts and arid conditions. However, there were also areas with lush forests and extensive swamps. The Triassic saw the diversification and emergence of several new groups of organisms. Reptiles began to dominate the land, with the rise of archosaurs, which eventually gave rise to dinosaurs, crocodiles, and birds.

The first mammals and turtles also appeared during this period. Marine life recovered gradually after the Permian extinction. Ammonites, which are shelled cephalopods, became important marine organisms, and new groups of fishes, such as ray-finned fishes, emerged. Invertebrates like corals, sponges, and mollusks also diversified. Plants in the Triassic included conifers, cycads, and ferns, but flowering plants had not yet evolved. The land was mainly inhabited by fern-like plants and gymnosperms. Towards the end of the Triassic Period, another mass extinction event occurred, known as the Triassic-Jurassic extinction event. This event, although not as severe as the Permian extinction, had a significant impact on the Earth's ecosystems and paved the way for the dominance of dinosaurs during the Jurassic Period.

Jurassic 201-145 M.Y.A

The Jurassic was a geological period and stratigraphic system that extended from about 201 to 145 million years ago. The Jurassic was characterised by a warm, humid climate, lush vegetation and abundant life. On land, the fauna changed from a Triassic fauna dominated jointly by dinosaurs and pseudosuchian archosaurs to one dominated solely by dinosaurs. The first birds appeared during the Jurassic, evolving from a branch of theropod dinosaurs.

The first sharks, rays and crabs also appeared. The end of the Jurassic is marked by a faunal turnover, with the increase in diversity of some groups and the decline of others.

Cretaceous 145-66 M.Y.A

The Cretaceous is a geological period that started 145 million years ago and ended around 66 million years ago with the Cretaceous-Paleogene mass extinction event. It was the third and final period of the Mesozoic Era and it was the longest, lasting around 79 million years. It was also sub-divided into the Early Cretaceous and the Late Cretaceous. This period of time had a relatively warm climate that made the sea level rise. The gymnosperm trees started to disappear as the flowering plants began to become more common.

The oceans and seas were populated with now-extinct marine reptiles, ammonites, and rudists. Dinosaurs continued to be the most abundant species on land. This period ended with the Cretaceous-Palogene mass extinction which was caused by a meteror hit in the Yucatan peninsula, killing more than 75% of the species in the world at that time.