mesozoïcum

Mesozoïcum, known in English as the Mesozoic Era, is the geological era that spans roughly 252 to 66 million years ago, between the Paleozoic and Cenozoic. It is characterized by the rise of dinosaurs, the first birds, and major evolutionary innovations in plants and animals. The era is divided into three periods: Triassic, Jurassic, and Cretaceous.

During the Triassic (about 252–201 million years ago), life recovered from the Permian extinction and the supercontinent Pangaea began to break apart. The Jurassic (201–145 Ma) saw further fragmentation of landmasses, warm global climates, and the peak diversification of dinosaurs. The Cretaceous (145–66 Ma) featured high sea levels, thriving dinosaurs, and the rise of flowering plants.

Ecologically, the Mesozoic hosts marine reptiles, pterosaurs, and diverse marine life alongside herbivorous and predatory dinosaurs. Early birds appear in the late Jurassic, and mammals remained small. Plants were dominated by gymnosperms early on, with angiosperms (flowering plants) expanding in the late Cretaceous.

Toward its end, the Mesozoic ended with a mass extinction about 66 million years ago, extinguishing most dinosaurs and many other groups. The causes include an asteroid impact at Chicxulub and large-scale volcanism of the Deccan Traps, along with climatic changes. The extinction event paved the way for the Cenozoic, when mammals and birds diversified to occupy many ecological roles left vacant by the dinosaurs.