Science 7
Unit 2
Earth & Life History
Name: ______________________________
Date: ______________ Period: __________
Sec 5.3 Earth’s Past is Revealed in Rocks and Fossils
Fossils and original remains give clues about the past.
1. What are fossils?
Types of Fossils
2. List three different types of fossils.
________________________ ________________________
________________________
Fossil Formation
3. Rock fossils form mostly in what type or rock? Why are fossils not found in igneous rock?
____________________not igneous because____________________________________________
4. Which of the organisms below is least likely to become preserved in a fossil? Explain why this is so.
_____________________because ____________________________________________________
Fossils in Rocks
5. A worm leaves a mark in the sediment as it burrows and searches for food. What kind of fossil would
this become? ______________________________________________________
6.
6. Fill in the concept map for fossils in rocks.
7. What kind of fossil is illustrated in the picture below? ______________________
Original Remains
8. Name three examples of original remains. a. _____________________________________
b. ______________________________ c. _____________________________________
9. The soft parts of dead plants and animals do not often become fossils because they decompose. List
three substances that might prevent decay.
________________________
________________________
________________________
Fossils and other natural evidence show changes in life and the environment.
10. Suppose the fossil of an ancient fish was discovered high atop a mountain. What might this indicate
about Earth’s past?
___________________________________________________________________
11. What are the earliest fossils? What do they indicate about the environment in which they lived?
___________________________________________________________________
Ice Cores and Tree Rings
12. Ice cores and tree rings provide geologists with a lot of information. Increases in ash in ice rings give
evidence of ___________________________. Scientists can study tree rings to develop
________________________________.
13. How are ice cores useful to scientists?
___________________________________________________________________
14. What does it mean if a tree ring for a particular year is thin?
___________________________________________________________________
Finding the Age of Fossils
15. What are the two ways scientists use to determine the age of fossils?
__________________________________ _________________________________
16. Why does radiometric dating usually not work on very old fossils?
___________________________________________________________________