The Fossil Record Documents the History of Life

Name Period

Chapter 25: Tracing Phylogeny Overview The fossil record documents the history of life

1. In what type of rock are fossils found?

2. Rocks and fossils are dated in several ways. Explain the difference between Relative Dating and Radiometric Dating.

3. What is the age range for which carbon-14 dating may be used?

4. To date fossils outside the rage of carbon-14 dating, researchers use indirect methods of establishing absolute fossil age. Explain how this could be done using radioisotopes with longer half- lives.

5. What are three groups of tetrapods?

Key events in life’s history include the origins of single-celled and multicelled organisms and the colonization of land

6. What was the earliest form of life on the planet? How long ago did this life-form first occur?

7. What unique ability was originated with cyanobacteria? How did this alter life on Earth and lead to a wave of mass extinctions?

8. The first eukaryotes did not appear until approximately 2.1 billion years ago. Explain the evolution of eukaryotes by endosymbiosis. (p.522-524 or online)

9. Summarize three lines of evidence that support the model of endosymbiosis. (p.522-524 or online) The rise and fall of groups of organisms reflect differences in speciation and extinction rates

10. If you have not studied geology, you will find this concept introduces a fascinating look at the changes in our planet as explained by continental drift. Define continental drift. How can continents move?

11. A mass extinction is the loss of large numbers of species in a short period, caused by global environmental changes. What caused the Permian mass extinction 250 million years ago (mya)? Summarize the species that were lost.

12. A second important mass extinction is the Cretaceous mass extinction that happened about 65 mya. Everyone’s favorite group, the dinosaurs, was lost, along with more than half of all marine species. What caused it?

13. What are adaptive radiations?

14. Why did a large-scale adaptive radiation occur after each mass extinction?

15. What is systematics? How is it used to develop phylogenetic trees?

Phylogenies show evolutionary relationships

16. What’s taxonomy?

17. Every organism on Earth may be referred to by a unique binomial, or a two-part name. These are in Latin, or latinized. What is your binomial? What does it mean? 18. What are the two components of every binomial?

19. Taxonomy uses hierarchical categories that nest within each other, like Russian dolls. The figure below shows the categories, each called a taxon. Label each taxonomic category and then give the one that applies exclusively to this panther to the side of each box.

D K P C O F G S or Dear King Phillip Comes Over For Good Spaghetti

20. So, which are more closely related, organisms in the same phylum, or those in the same order?

21. Here is a phylogenetic tree. Recall that branch points represent common ancestors of the two lineages beyond the branch or node. Circle the common ancestor of badgers and otters, and label it as A. Circle the common ancestor of cats and dogs, and label it as B.

Shared characters are used to construct phylogenetic trees

22. The following figure shows three cladograms. What is a clade? Circle a clade that is not highlighted below.

23. Why is Group I monophyletic?

24. Explain why Group II is paraphyletic.

25. What is a polyphyletic group? 26. Clades are derived by using shared derived characters. What are these?

27. Explain why for mammals, hair is a shared derived character, but a backbone is a shared ancestral character.