Geological Time: 648-650 Name____________________________________
Per______ Date___________________
Group 1: Fossils and the Rock Record
1. Place eras, periods, eons, and epochs in order from longest period of time to shortest.
Shortest Longest
2. What does the law of superposition state?
3. Fossils are the remains of __________ and _____________ that once lived on Earth.
4. __________________ ___________________ uses the decay rates of different types of radioactive minerals to determine the actual age of rocks or fossils.
Group 2: The Precambrian
1. How old is Earth?
2. Why was the early Earth hot? a. b. c.
3. How did Earth’s early atmosphere and oceans form?
4. What was the source of almost all of the Oxygen in the atmosphere?

Group 3: Early/Middle Paleozoic Era
1. Early in the Paleozoic, a shallow sea covered the ancient North American continent of ________________, which was located near the _______________.
2. During the middle Paleozoic Era, minerals like gypsum and halite formed because:
3. The following organisms dominated the seas: a. b. c.
4. _____________ evolved as the top predators.
5. _____________ moved on to land.
6. What is a mass extinction?
Group 4: Late Paleozoic Era
1. What supercontinent formed?
2. What is the difference between a glacial and an interglacial period?
3. What happened to the oceans during glacial and interglacial periods?
4. __________ and the ___________ _________ developed, which allowed __________ and ___________ to move onto dry land.
5. What happened at the end of the Permian Period?

Group 5: Mesozoic Era
1. What happened to Pangaea?
2. What caused that to happen to Pangaea?
3. _________ were the most common land plants and ________________ were the dominant land animals.
4. What happened at the end of the Cretaceous Period that might have led to the extinction of the dinosaurs?
5. What might have evolved from dinosaurs?
Group 6: Cenozoic Era
1. During the Pleistocene ice ages, how far did glaciers extend?
2. After the ice ages, these covered much of Central North America.
3. ___________ ______________ evolved to feed in Central North America.
4. Why did grazers become extinct when ice ages approached?
5. Primates emerged during the Cenozoic. What is a primate?