Section Review 9-3Section Review 9-3

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Permian mass extinctionsPermian 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.

#1#1List the periods of the Mesozoic Era and describe one

major life-form in each division.

Triassic: ammonites

Jurassic: dinosaurs

Cretaceous: flowering plants

#2#2Identify two major geologic and two major biological developments of the Mesozoic Era.

Geologic: Pangaea broke apartMajor meteorite impact

Biological: Birds first appearedFlowering plants appeared

#3#3List 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

#4#4Identify two major geologic and two major

biological developments of the Cenozoic Era.

Geologic: continents moved to their present locationsice sheets advanced and retreated several times

Biological: mammals became dominanthumans developed

Break up of PangaeaBreak up of Pangaea

#5#5Explain 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.

#6#6Identify the era, period, and epoch we are in today.

Cenozoic EraQuaternary PeriodHolocene Epoch

#7#7Describe 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.

88. Suppose you have a shark’s tooth . Suppose you have a shark’s tooth that you suspect is about 15,000 that you suspect is about 15,000

years old. Would you use years old. Would you use 238238U or U or 1414C C to date the tooth? Explain your to date the tooth? Explain your

answer.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.

The End????The End????

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