1. The preserved or mineralized remains of an organism is a _____________________
2. Intermediate forms are also called _________________________
3. Most scientists agree that the earth is about __________ billion years old.
4. Give one reason why we do not have fossils of every organism that ever lived on the earth. _________________________________________________________________
5. A person who studies fossils is called a(n) __________________________________

6. Whale Evolution - Fill out the chart below using the information from Figure 13-9

	Name of Organism	When it Existed	Method of Movement
	modern whale

7. A ___________________________ is a species from which two or more species have diverged.
8. Species that share a more recent common ancestor will have [ more / fewer ] amino acid differences.
9. A _________________________ shows how organisms are related through evolution.

10. Humans are more closely related to a [ chicken / gorilla ] than they are to a frog.
11. Structures that are reduced in size or serve no important functions are called _____________________________
12. The forelimbs of all vertebrates share the same basic bones. This is an example of _____________________________
13. Using figure 13-13, which vertebrate has the longest phalanges? ______________
14. The evolutionary history of organisms can also be seen in the development of ______________________________
15. Using Figure 13-14, which species have a tail at some point during the embryological development? _____________________________________________
16. The model in which gradual change leads to species formation is called ___________________________________
17. The model in of evolution in which periods of rapid change occur is called ___________________________________

Exploring Further (page 289)

18. What kinds of drastic events can lead to changes in climate? ________________
___________________________________________________________________

19. Draw a diagram of gradualism

20. Draw a diagram of punctuated equilibrium