Name: _______________________________________ Date: ________________ Period: _____
Views of Earth’s Past
Read chapter 2 section 1 (pages A45 through A51) and answer the following questions.
1. What do scientists study to learn about Earth’s changes?
2. How long ago did dinosaurs become extinct?
3. What are two examples of dinosaur fossils?
4. Scientists have formed a theory about how the dinosaurs became extinct. They think that a
__________________ __________________ (like ______________________________________________
______________________________________________) led to ____________________ atmospheric or
other changes.
5. What are most fossils?
6. What are original remains?
7. List the three places where original remains are preserved. List one type of fossil found in each place.
8. Which is more likely to be preserved as a fossil: a bone or a leaf?
9. In what type of rock are fossils found?
10. List the four kinds of fossils that form in rocks. Using the information on page A48 and A49, explain how
each of the four are formed.
11. According to fossil evidence, has Earth stayed the same or changed over time?
12. What kinds of fossils found in the South Pole region prove that the South Pole was once much closer to the
equator?
13. What are the earliest known fossils?
14. Why are tree rings an important part of learning about Earth’s past?
15. How deep and how old is some of the ice found in Greenland and Antarctica?
16. What do scientists analyze when they examine ice cores?
Read chapter 2 section 2 (pages A53 through A59) and answer the following questions.
1. What is relative age?
2. Give an example of something that you know the relative age of. What information did you use to
determine the relative age?
3. Do scientists still use relative age dating today?
4. Where are the oldest rock layers normally found in undisturbed rock layers?
5. Where are the youngest rock layers normally found in undisturbed rock layers?
6. What can disturb rock layers?
7. How can igneous rock disturb sedimentary rock layers?
8. How do fossils in sedimentary rock layers provide information about the age of the rock or how long ago it
formed?
9. What are index fossils?
10. How does an index fossil tell the age of a rock?
11. Look at the chart on page A56. If a fossil of a fish were found beside a Nerinea trinodosa, it would have
lived between ______ and ______ mya (million years ago).
12. What is absolute age?
13. What is the difference between relative age and absolute age?
14. What is radioactivity?
15. What object does our text compare radioactivity to? Why does it compare it to this object?
16. Explain half-life.
17. Look at page A58. How do the relative amounts of uranium 235 and lead 207 in the igneous rock change
over time?
18. In what type of rock does radioactive dating work best?
19. What do scientists use Carbon 14 to date?
20. How might the absolute age of an igneous rock layer help scientists to determine the ages of nearby
sedimentary rock layers?