Cretaceous Period

The Cretaceous Period is the third and final period of the Mesozoic Era, spanning from about 145 to 66 million years ago. It is known for being the period in which dinosaurs were the dominant terrestrial vertebrates and for the emergence of flowering plants.

Climate

The climate during the Cretaceous Period was generally warm and mild, with high sea levels and a relatively stable climate. However, there were fluctuations in temperature and sea levels during this time.

Geography

During the Cretaceous Period, the continents were still in the process of breaking apart from the supercontinent Pangaea. This resulted in the formation of new oceans and the separation of landmasses, leading to the development of distinct biogeographic regions.

Life Forms

The Cretaceous Period saw the evolution and diversification of many new groups of organisms, including the rise of flowering plants (angiosperms) and the emergence of new types of dinosaurs. It was also a time of significant diversification among marine reptiles and the emergence of early mammals.

Extinction Event

The Cretaceous Period ended with a mass extinction event about 66 million years ago, which led to the extinction of the non-avian dinosaurs, as well as many other forms of life. This event is thought to have been triggered by a combination of volcanic activity, asteroid impact, and climate change.

Study Guide

• What is the Cretaceous Period?
• Describe the climate during the Cretaceous Period.
• How did the geography change during the Cretaceous Period?
• What were some of the key life forms that emerged during the Cretaceous Period?
• What caused the mass extinction event that ended the Cretaceous Period?

[Cretaceous] Related Worksheets and Study Guides:

• Geologic timeScience • Eighth Grade