The Cretaceous Period - The period that ended Mesozoic Era

#cretaceous #mesozoic #jurassic

The Cretaceous period, the period that ended the mesozoic era, lasted from 146 to 65 million years ago. During this period, Gondwanaland and Laurasia were divided into smaller land-masses that more closely resembled those of the modern continents. The climate remained mild and moist but the seasons became more marked. Many cycads, seed ferns, and conifers have been replaced by flowering plants and deciduous trees. With the evolution of new mammals, insects, fish, crustaceans, and turtles,animal species have become more varied. Dinosaurs evolved into a wide variety of species during Cretaceous times; more than half of all known dinosaurs - including Iguanodon, Deinonychus, Tyrannosaurus, and Hypsilophodon-lived during this period. However, dinosaurs became extinct at the end of the Cretaceous period. It is still unknown how the mass extinction occurred, but it is thought to be caused by climatic changes due to either a catastrophic meteor impact with the Earth or extensive volcanic eruptions.