If you have been keeping up with the Geosciences section, you may know that the last two months, the climate of the Triassic period and the Jurassic period were covered, in a mini-series designed to look at the climate of the different periods of the Mesozoic era. Now, a closer look at the last period in the Mesozoic era, the Cretaceous period (145 – 65 million years ago), will be reviewed.
The early Cretaceous was not much different than the late Jurassic. Sea levels continued to rise as continents continued to move, and tectonic plates continued to shift. As was happening in the Jurassic period, dinosaurs were evolving independent of one another, and becoming more and more specialized. One of these specialized predators includes the infamous Tyrannosaurus Rex.
Vegetation wise, the first of the angiosperms (flowering plants) started to grow. These plants started off small and weedy during the early Cretaceous, but by the late Cretaceous, large flowers had begun to form. These angiosperms had allowed a lot of grazing dinosaurs, like Triceratops, to flourish.
The end of the Cretaceous also saw a rise in today’s dominant life form: mammals. None of the mammals got any larger than a cat or small dog, most being mouse- or rat-size. Another evolution seen in the Cretaceous were small reptiles and amphibians, such as salamanders, turtles, or lizards.
It was also the end of the Cretaceous that changes in climate would start dramatically affecting future life on earth. Sea levels started to fall again, and temperatures started to lower. Volcanic activity was also occurring, causing a global cooling.
From here, the story is one we all know the ending to: A large asteroid collided with Earth, and more than half of the world’s animals, including the dinosaurs, went extinct. Despite this melancholy ending, the dinosaurs still remain some of the most fascinating creatures, and by looking at the climate of the Mesozoic era, a better understanding of them can be appreciated.
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© 2018 Weather Forecaster Joseph Fogarty