1. Chapter 9 Section 1 Review Page 211-214

2. #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)

4. #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 ).

5. Geologic Columns

6. #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

7. #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.

8. #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.

9. Chapter 9 Section 1:
Geologic Time

11. 1
The geologic _____ ______ is a table that outlines the development of _______.
time scale
Earth

12. 2
The geologic column is an ordered arrangement of rock layers ______ on their ____.
based
ages

13. 3 On a geologic column, the ______ _____ are on the _______.
oldest rocks
bottom

14. 4
Scientists created the first _________ __________ by determining the relative ages of sedimentary rock in areas all over the world.
geologic
column

15. 5
Scientists have most accurately determined the _______ ages of rock layers by using radiometric dating methods.
absolute

16. 6
Rock _______ that match a similar layer in a geologic column may have formed at the ______ time.
layers
same

17. 7
_______ fossils can be used to _____ rocks.
Index
date

18. 8
Geologic time is divided into ______ ______.
four eons

19. 9 A _______ is a unit of geologic time into which an era is divided.
period

20. 10
A geologic _________ is usually named for the place where its characteristic ______ were first discovered.
period
fossils

21. The End????