Phanerozoic the Mesozoic features the rise of reptiles on their 150 million year conquest of the Earth on the land, in the seas, and in the air. There are three periods in the Mesozoic: Triassic, Jurassic, and Cretaceous. The Triassic ranges from 250 million to 200 million years ago. The Triassic is a transitional time in Earth's history between the Permian Extinction and the lush Jurassic Period. It has three major epochs: Early Triassic, Middle Triassic and Late Triassic. The Early Triassic lasted between 250 million to 247 million years ago, and was dominated by deserts as Pangaea had not yet
Early Triassic have revealed that temperatures rose in the first 3 million years of the Triassic, ultimately reaching sea surface temperatures of in the tropics around 249 million years ago. Large and mobile species disappeared from the tropics, and amongst the immobile species such as molluscs, only the ones that could cope with the heat survived; half the bivalves disappeared. On land, the tropics were practically devoid of life. Big, active animals only returned to the tropics, and plants recolonised on land when temperatures returned to normal around 247 million years ago. Early Triassic The Early Triassic is the first of three