Chapter 9 Section 1 Review Page 211-214

#1 Describe the major events in any one period of geologic time. Example: During the Devonian Period fish dominated Earth and amphibians first appeared. (see page 213; the Geologic Time Scale for more)

#2 Explain why constructing geologic columns is useful to Earth scientists. A geologic column is useful because it shows the relative ages of fossils and rocks. (see Figure 1 on page 211 for example ).

Geologic Columns

#3 From shortest to longest: year, age, epoch, period, era, eon List the following units of time in order of length from shortest to longest: year, period, era, eon, age, and epoch. From shortest to longest: year, age, epoch, period, era, eon

#4 When a scientist discovers a new type of fossil, what characteristics of the rock around the fossil would he or she want to learn first? The first thing a geologist would want to learn is the age of the rock in which the fossil was found.

#5 How would our understanding of Earth’s past change if a scientist discovered a mammal fossil from the Paleozoic Era? It would change our thinking completely because we would have to rethink the entire evolution of animals and the conditions on Earth all the way back to and including the Paleozoic. That is 500 million years of geologic history to rewrite.

Chapter 9 Section 1: Geologic Time

1 The geologic _____ ______ is a table that outlines the development of _______. time scale Earth

2 The geologic column is an ordered arrangement of rock layers ______ on their ____. based ages

3 On a geologic column, the ______ _____ are on the _______. oldest rocks bottom

4 Scientists created the first _________ __________ by determining the relative ages of sedimentary rock in areas all over the world. geologic column

5 Scientists have most accurately determined the _______ ages of rock layers by using radiometric dating methods. absolute

6 Rock _______ that match a similar layer in a geologic column may have formed at the ______ time. layers same

7 _______ fossils can be used to _____ rocks. Index date

8 Geologic time is divided into ______ ______. four eons

9 A _______ is a unit of geologic time into which an era is divided. period

10 A geologic _________ is usually named for the place where its characteristic ______ were first discovered. period fossils

The End????