1. PaleontologyStudy Guide Answers Please take a sheet of paper and label it “extra info”

2. #1 How do scientists date material older than 50,000 years? Younger than 50,000? • Older than 50,000 = Uranium lead Method • Younger than 50,000 = Carbon-14 Method

3. #2 What type of rock are most fossils found in? Sedimentary

4. #3 What can fossils tell us about an area’s history? • Where dry land was once under water Example: shark tooth in Georgia • How the environment has changed

5. #4 What does the law of superposition state? • Younger rocks are on the top. • Older rocks are on the bottom. • Layers must be undisturbed

6. #5 What is petrification? • Mineral Replacement • Usually happens to wood or bones

7. #6 List the Geological era’s in order from earliest to most recent Precambrian Paleozoic Mesozoic Cenozoic *Currently we are in the cenozoic Hint: Think Alphabet

8. #7 How old is the Eath’s History date back to? Approximately 4.6 BILLION Years

9. #8 What’s the difference between index and trace fossils Trace fossils are indirect evidence of prehistoric life. • Can tell us about the activityof an animal • Examples: Footprints, trails, poop Index fossils are used to determine relative age. Index fossils are widespread geographically, are limited to a short span of geologic time, and occur in large numbers. It’s an actual FOSSIL

11. #9 What is relative age and how do you find the relative age? • Sequence • Age COMPARED to other rocks • Older or younger • NO NUMBER • Uses: • Index fossils • Law of superposition • Law of original horizontality

14. #10 What is absolute age? • Most precise • Gives an actual age • Puts a number to the age. This is why we use it! Uses: • Radioactive decay • Carbon 14 or uranium lead • Half-life

18. #11 What can scientists learn from studying fossils? • Geological changes such as dry areas that were once under water • Organisms have become more complex and how they have evolved • How the environment looked in the past • How rock layers in different areas match up • How environment/animals have changed • The age of certain layers of rocks

19. #12 What is uniformitarianism? What is original horizontality Uniformitarianism – the idea that the same geologic processes shaping the Earth today have been at work throughout Earth’s history

20. The principle of original horizontality means that layers of sediment are generally deposited in a horizontal position.

21. #13 How is the geologic time scale broken down Eons-eras-periods-epochs • Broken up so it’s more manageable • Eras are broken by a huge climate change or mass extinction

22. #14 What slows down the decaying process Dry And Freezing Temperatures

23. #15 What do scientists think caused the extinction of dinosaurs? Climate change Maybe: Pange breaking apart Or Asteroid causing a huge dust cloud

25. #16 Are fossil records complete or incomplete? Why? Incomplete Most organisms don’t become fossils

26. #17 What is a catastrophic event? Flood, mudslide, volcanic ash, earthquake, etc. Can lead to the formation of fossils

27. #18 cast vs. mold Mold: cavity where an organism once was (cakepan) Cast: sediment that fills the cavity (batter)

29. #19. How are fossils formed? Needs to have a rapid burial and have the hard parts of the organism be preserved!!!

30. #20. what do fossil records tell us about organisms They’ve become more complex One cell to humans