Visit our textbook-specific Online Learning Center Web site at www.mhhe.com/relethford8e to access the exercises that follow.
The Scientific Case for Common Descent
The site "29 + Evidences for Macroevolution: The Scientific Case for Common Descent" (http://www.talkorigins.org/faqs/comdesc/) delves further into the subject of macroevolution. It provides evidence that favors both common descent and macroevolution.
Read through the "Introduction" section. You will learn more about the definition of universal common descent and evidence supporting it.
What is considered "scientific evidence"? If you wish to read more about it, click on the following link to "Scientific 'proof,' scientific evidence, and the Scientific Method": http://www.talkorigins.org/faqs/comdesc/sciproof.html.
Now, define universal common descent.
Do you think that there is any validity to this theory? Why or why not?
Name three mechanisms by which speciation occurs. Come up with an existing example for each type (e.g., Darwin's finches demonstrate adaptive radiation).
What evolutionary process do the house mice of Madeira demonstrate? How did the island's original house mouse population evolve into six separate "races" or species?
What Killed the Dinosaurs?
http://www.pbs.org/wgbh/evolution/extinction/dinosaurs/index.html.
Visit the PBS Web site on evolution and extinction. Follow the animated program "What Killed the Dinosaurs?" You will arrive at a table of "Hypotheses and Evidence" about the demise of the dinosaurs.
Click on the various hypotheses, and watch the animations that explain them. You also can click on the bodies of evidence to examine them.
Which hypothesis seems most probable to you? Why?
Which hypothesis has the most convincing evidence to support it?
Now click on the "Conclusion" link and read it. Does this conclusion agree with your own? This mystery is open-ended, so the PBS conclusion is not necessarily the only possibility.
Do you have an alternative interpretation of the evidence?
