Name:_____________________ Chapter 8 Review Directions: Please answer the following questions using complete sentences. 1. Define the term fossil and describe what fossils help scientists have a better understanding of. 2. What is an index fossil? 3. What percentage of organisms actually end up apart of the fossil record? 4. What type of rock are fossils generally found in? (metamorphic, sedimentary, or igneous) 5. Define radioactive dating and half-life. Does radioactive dating help us determine the relative or absolute age of rocks? 6. Define the law of superposition and uniformitarianism. 7. Older fossils that are found lower in the rock layers tend to be simpler/more complex than fossils of more recent organisms. (circle the correct option) 8. The geologic time period is broken up into main ___________________ which are then broken up into smaller ____________________. 9. Define petrified fossil and trace fossil and describe the difference between the two. 10. What is an intrusion? Is it older or younger than the surrounding layers? 11. What are three different object that can fossilize? 12. What are three different WAYS that objects can be fossilized? 13. Review the different fossils that are shown to you in class Wednesday. What are the names of the fossils? 14. What can a fossilized tooth tell us about the organism? 15. True/False: Most fossils are 2 million years old. ***Study the fossil quiz, the great fossil find sheet, the law of superposition lab, the handouts from class on radioactive dating and geologic time, this review guide, and the book.