Cretaceous Period

The Cretaceous Period is the third and final period of the Mesozoic Era, spanning from approximately 145 to 66 million years ago. It is named after the Latin word "creta," meaning chalk, which is abundant in the rocks formed during this time.

Geology

During the Cretaceous Period, the supercontinent Pangaea continued to break apart, leading to the formation of the Atlantic Ocean. The period was characterized by extensive shallow seas and a warm climate, resulting in high sea levels.

Climate

The climate of the Cretaceous was generally warm and temperate, with no polar ice caps. The high sea levels and warm temperatures led to the development of diverse marine ecosystems and lush vegetation on land.

Flora and Fauna

The Cretaceous Period saw the evolution of diverse plant and animal life. On land, the first flowering plants (angiosperms) appeared, leading to the spread of forests and the diversification of herbivorous and carnivorous dinosaurs. In the oceans, marine reptiles such as plesiosaurs and ichthyosaurs thrived, along with diverse mollusks and other marine invertebrates.

Extinction Event

The Cretaceous Period ended with a mass extinction event approximately 66 million years ago, marking the boundary between the Cretaceous and the subsequent Paleogene Period. This event is widely attributed to the impact of a large asteroid or comet, which led to the extinction of non-avian dinosaurs, as well as many other plant and animal species.

Study Guide

1. What is the significance of the name "Cretaceous"?
2. Describe the geological changes that occurred during the Cretaceous Period.
3. Explain the climate of the Cretaceous and its impact on ecosystems.
4. Discuss the evolution of flora and fauna during the Cretaceous Period.
5. What caused the mass extinction event at the end of the Cretaceous Period?

Use this study guide to review and deepen your understanding of the Cretaceous Period and its importance in the history of the Earth.

[Cretaceous] Related Worksheets and Study Guides:

• Geologic timeScience • Eighth Grade