Earth During the Mesozoic Era

The time is about 250 million years ago. The Paleozoic Era has come to an end. The Mesozoic Era is beginning. The Mesozoic Era is divided into three periods. The first is the Triassic Period. In the Triassic Period, Pangaea is beginning to break up. The ocean floor is slowly expanding along the rifts between land masses. New oceans will soon form. Dinosaurs first appeared.

The climate in the Triassic Period is unusual. The land is still in a large mass. Much of the land is far from the ocean. This causes extreme conditions. Over all the Earth, the temperature is warm. There is little change between the equator and the poles. However, on land there are big changes. On land the temperature changes a lot with the seasons. Summers are very hot. Winters are very cold. Most of the time, the weather is dry. During parts of the year, though, monsoons bring heavy rainfall.

After 50 million years, the Triassic Period comes to an end. As the Jurassic Period begins, Pangaea is now two separate land masses. The ocean has entered the space between the two. The water helps stabilize the weather on land. Temperatures fluctuate less. Humidity increases. The climate becomes wetter.

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