Lesson 3.1: The Great Cooling

In this lesson, you leave behind the age of dinosaurs. As well, you watch seas drain, climates become cooler, grasslands expand, and mammals flourish.

• Read pages 368 to 371 of the textbook. Answer the questions as you encounter them.

Check your answers with those in the “Practice Answers” in the online course.

Temperatures in the distant past can be inferred from the number of fossils of animals, plants, or merely pollen grains found in sedimentary rock. But inferences can also be based on something far less obvious—the nuclear properties of oxygen atoms found in sedimentary rock at the ocean’s bottom. You will find more information in the next investigation.

 

• Read “3.1 Summary” on page 374 of the textbook. Then, complete “3.1 Questions”.
  
  Check your answers with those in the “Suggested Answers” in the online course.

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Go to Assignment 3.1: The Great Cooling.