1. The Changing Earth Chapter 4: Views of Earth’s Past

2. Section 4.1 Earth’s Past is Revealed in Rocks and Fossils

4. Continued – See page 112

6. Continued – See page 113

7. Continued – See page 115 Some fossils are not original remains, but rather impressions or traces made of rock. They provide indirect evidence of the organism (example: shoe print)

12. Section 4.2 Rocks Provide a Timeline for Earth

14. Continued – See page 120

15. Continued – See page 121

17. Continued – See page 122

19. Continued – See page 123

20. Continued Sr-87 Strontium 47.0 billion years Rb-87 Rubidium Pb-208 Lead 14.1 billion years Th-232 Thorium Pb-206 Lead 4.5 billion years U-238 Uranium Ar-40 Argon 1.3 billion years K-40 Potassium Decay Product Half-Life Element Common Radioactive Elements Used for Dating Rocks

21. Continued – See page 124 Scientists use the breakdown or radioactivity of atoms to determine relative ages of rocks.

22. Section 4.3 The Geologic Time Scale Shows Earth’s Past.

26. Continued – See page 130

27. Continued – See page 131

28. Continued – See page 132