REVIEW FOR CHAPTER 12
NAME___KEY_______
Key Terms to know: SEE THE BOOK AND YOUR VOCABULARY TERMS FROM NOTES
Principle of Uniformitarianism
Altered remains
Trace fossil
Principle of cross-cutting relationships
Relative dating
Principle of fossil succession
Law of superposition
Correlation
Unconformity
Index fossil
Disconformity
Radioactivity
Nonconformity
Radiocarbon dating
Geologic Time Scale
Eon
Phanerozoic
Paleozoic
Review Questions:
1. In what type of rock do geologists find evidence of past life? SEDIMENTARY
2. What type of geologic events can be recorded in rock? VOLCANIC ACTIVITY
3. What did each of the following scientist contribute to determining Earth’s history:
a. James Hutton PRINCIPLE OF UNIFORMITARIANISM
b. Nicolas Steno LAW OF SUPERPOSITION
c. John Wesley Powell FIRST TO NAVIGATE THE COLORADO RIVER
4. What are fossils and where are they found? REMAINS OR TRACES OF PREHISTORIC LIFE,
SEDIMENTARY ROCK
5. What type of environment will you not find fossils? IGNEOUS ROCK FORMED BY COOLING
MAGMA
6. What determines the type of fossil that is formed? THE CONDITIONS UNDER WHICH THE
ORGANISM DIED AND HOW IT IS BURIED
7. What type of fossil if petrified wood? ALTERED REMAINS
8. What type of fossil is a dinosaur footprint? TRACE FOSSIL
9. What is important to an organism becoming a fossil? RAPID BURIAL OR HARD BODY
PARTS
10. For organisms that have a shell, what environments would they most likely be preserved?
BOTTOM OF A LAKE BURIED BY A LANDSLIDE
11. Why would worms stand a poor chance at becoming a fossil? WORMS HAVE NO HARD
BODY PARTS
12. What must be true for fossils to be index fossils? ORGANISM MUST BE WIDESPREAD
GEOGRAPHICALLY, MUST BE ABUNDANT, LIMITED TO A SHORT SPAN OF
GEOLOGIC TIME
13. Radiometric dating is possible because why? DECAY OF ISOTOPES IS CONSTANT
14. What is a half-life? TIME THAT IT TAKES FOR A RADIOACTIVE ISOTOPE TO
TRANSMUT INTO A STABLE ISOTOPE
15. Review half-life problems given in class. SEE CLASS PROBLEMS
16. What 2 isotopes do geologists use for radiocarbon dating? CARBON-12 AND CARBON-14
17. Where does carbon-14 found in living organisms come from? CARBON DIOXIDE IN THE
ATMOSPHERE
18. Give an example of how radiocarbon dating could be used. DATE BONE OF ANIMALS 60000
YEARS OLD
19. What length of time does the geologic time scale cover? 4.6 BILLION YEARS
20. What is the currently accepted age of Earth? 4.6 BILLION YEARS
21. Put the following in order from longest to shortest: epoch, period, eon. ERA, PERIOD, EPOCH
22. When did abundant fossil evidence appear in the geologic record? 540 MILLION YEARS AGO
23. Most of Earth’s history occurred during what time period? PRECAMBRIAN