1. Section Review 9-3
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2. Permian mass extinctions
A theory that an abrupt and dramatic rise in atmospheric levels of carbon dioxide triggered the massive die-off 251 million years ago.

3. #1
List the periods of the Mesozoic Era and describe one major life-form in each division.
Triassic: ammonites
Jurassic: dinosaurs
Cretaceous: flowering plants

4. #2
Identify two major geologic and two major biological developments of the Mesozoic Era.
Geologic: Pangaea broke apart
Major meteorite impact
Biological: Birds first appeared
Flowering plants appeared

5. #3
List the periods and epochs of the Cenozoic Era and describe one major life-form in each division.
Tertiary Period
Paleocene Epoch: rodents
Eocene Epoch: horses
Oligocene Epoch: cats
Miocene Epoch: grazing herds
Pliocene Epoch: bears
Quaternary Period
Pleistocene Epoch: mammoths
Holocene Epoch: humans

6. #4
Identify two major geologic and two major biological developments of the Cenozoic Era.
Geologic: continents moved to their present locations
ice sheets advanced and retreated several times
Biological: mammals became dominant
humans developed

7. Break up of Pangaea

8. #5
Explain how the ice ages affected animal life during the Cenozoic Era.
Ice ages led to the rise of hairy, warm-blooded mammals that could survive the cold.

9. #6 Cenozoic Era Quaternary Period Holocene Epoch
Identify the era, period, and epoch we are in today.
Cenozoic Era
Quaternary Period
Holocene Epoch

10. #7
Describe the worldwide environmental changes that set the stage for the Age of Mammals.
A combination of environmental changes and a meteorite impact caused the extinction of the dinosaurs and many other organisms, leaving many niches open for mammalian species to fill. Mammals were able to survive worldwide cooling and the following ice ages.

11. 8. Suppose you have a shark’s tooth that you suspect is about 15,000 years old. Would you use 238U or 14C to date the tooth? Explain your answer.
You would use radiocarbon (14C) dating because the object is organic and because it is too young to be accurately dated by using 238U.

12. The End????