Final answer:
The Mesozoic Era, notably the Age of Dinosaurs, was defined by the breakup of the supercontinent Pangea, leading to significant climatic and biological changes and culminating in the extinction of the dinosaurs.
Step-by-step explanation:
The Mesozoic Era, often referred to as the Age of Dinosaurs, was a period characterized by significant geological and biological changes that lasted from about 245 to 65 million years ago. This era was marked by the breakup of Pangea, the supercontinent that encompassed all of today's continents. This tectonic shift was one of the most significant occurrences in the Mesozoic, leading to altered climates, extensive volcanic activity, and eventually the dispersal of continental landmasses into their more modern configuration.
During the Mesozoic, Pangea started to separate into Laurasia and Gondwanaland, which respectively became today's Northern and Southern Hemisphere continents. This breakup began in earnest during the Jurassic period and continued through the era. The tectonic activities during this time had profound effects on the flora and fauna, contributing to massive extinctions, including the end of the dinosaurs at the close of the Cretaceous period due to an asteroid impact and volcanic activities. Following the Mesozoic, the Cenozoic Era saw mammals and birds dominate in new niches left by the extinct dinosaurs.