Mezozoik

Mezozoik, known in English as the Mesozoic, is the geologic era that stretches between the Paleozoic and the Cenozoic. The term is derived from Greek roots meaning middle life or middle animals, reflecting its position in the standard geologic timescale.

The era lasted roughly 186 million years, from about 252 to 66 million years ago. It is divided into three main periods: the Triassic (approximately 251.9–201.3 Ma), the Jurassic (about 201.3–145 Ma), and the Cretaceous (roughly 145–66 Ma). These subdivisions help scientists organize the evolution of life and the changing environments across vast spans of time.

Climate and geography during the Mezozoik were generally warmer than today, with high atmospheric carbon dioxide levels and a lack of extensive polar ice. The supercontinent Pangaea began to break apart in the Triassic, leading to rising sea levels and new coastal environments. This tectonic activity influenced global climate patterns and the distribution of organisms.

Biologically, the Mezozoik saw the rise and diversification of the dinosaurs, as well as other archosaurs, marine reptiles, and early mammals. The first true birds appeared in the late Jurassic, and flowering plants (angiosperms) emerged and diversified in the Cretaceous. Ecosystems included coastal lagoons, vast inland seas, and lush forests.

Two major mass extinction events mark the era’s end and its transitions. The end-Triassic extinction opened ecological niches later filled by dinosaurs, while the end-Cretaceous (K-Pg) extinction erased most non-avian dinosaurs and many other groups, paving the way for mammals and birds to become dominant in the following Cenozoic. The Mezozoik thus shaped modern animal and plant lineages and the configuration of Earth’s continents.