Mesozoic

The Mesozoic Era (from Greek mesos meaning "middle," and zoon meaning "animal" or "life"; meaning "Middle Life") is one of the three geologic eras of the Phanerozoic Eon, spanning from roughly 251.902 million to 66 million years ago. It is informally known as the Age of Reptiles, due to the dominance of reptiles, particularly dinosaurs, on land.

The Mesozoic Era is divided into three periods:

• Triassic Period: The earliest period, lasting from approximately 251.902 to 201.3 million years ago. It followed the Permian-Triassic extinction event, and was characterized by the initial diversification of reptiles and the emergence of the first dinosaurs.

• Jurassic Period: The middle period, lasting from approximately 201.3 to 145 million years ago. It saw the continued dominance of dinosaurs, including large sauropods and theropods. The first birds also appeared during this period.

• Cretaceous Period: The latest period, lasting from approximately 145 to 66 million years ago. It was characterized by the continued diversification of dinosaurs, as well as the appearance of flowering plants (angiosperms). The Cretaceous-Paleogene extinction event, which wiped out non-avian dinosaurs, marked the end of the Mesozoic Era.

Geologically, the Mesozoic was a time of significant plate tectonic activity. The supercontinent Pangaea began to break apart, leading to the formation of the Atlantic Ocean and the separation of continents into their modern-day configurations. Climates during the Mesozoic were generally warmer than today, with no evidence of widespread glaciation.