Topic 8 Review on Geologic Time

1. Sophia had been reading about the history of the Earth. She was surprised to learn about the different ways geologists learn about the age of rocks. Why is it important for geologists to use both relative and absolute ages to determine the age of rocks.

• Scientists want to know about the age of rocks.

• Scientists need only one way to determine the age of rocks.

• Scientists use the age of rocks compared to each other and themselves to get a better understanding of the rocks in rock layers

• Scientists are not interested in the ages of rocks.

2. Thomas was interested in how the disruption of rock layers can be used to find a rock's age. Which of the following are examples of how rock layers may be disturbed or changed?

• igneous intrusion

• superposition

• sedimentary rock layers

• index fossils

3. Geologists use index fossils to find the relative ages of rock layers and to determine how the layers at different locations correspond with each other. Which rock layers has an index fossil in the picture below?

• layers A and V

• layer V and B

• Layer F and Y

• Layer X and V

4 After looking at the diagrams below, Basheem noticed that the rock layers at location 4 differed from those at the other three locations What likely occurred at location 4?

• Location 4 held index fossils similar to other locations.

• Location 4 had heavy erosion and soon a rock layer will be deposited on top of it.

• Layer B was eroded away and layers C and D were deposited on top of it at a later time.

5. Ezra was interested in how geologists date rocks and she learned about two methods. She learned that potassium-40 and carbon-14 are used to find the _________ of ancient rocks.

• absolute age

• half life

• relative age

• a rock's color

6. Nikki was putting together a presentation on the geologic time scale to share in class. What is the purpose of the geologic time scale?

• to show the evolution of life forms and to model how these life forms behaved and what they ate

• to organize and sequence events in history of Earth and to serve as a model for the vast amount of time covered

• to determine the relative ages of rocks and when and how they formed; to create a timeline for their development

7. CHOOSE TWO THAT APPLY. Roman's part in a group project on the history of the Earth was researching and presenting on Precambrian time. CHOOSE TWO phrases that best characterize the Precambrian time?

• a time of great evolutionary change

• a time with multiple periods in it

• a time with few fossils

• a time that covers 88% of the Earth's history

8. Daniel recently read a news article about geologists updating the geologic time scale. How are geologists able to update the geologic time scale?

• because geologists are really smart and have degrees to do what they want

• because new physical evidence, such as a new index fossil, has been discovered

• because humans have been around for a very long time and are really smart

9. Javier was organizing his notes about the geologic time scale by matching major events to their eras. Please match the major event to its corresponding era below. During the _________Era, mammals were abundant.

10. Patrick learned about the geologic time scale at school. He grew interested in learning more about the mass extinctions that have taken place throughout the history of the Earth. Which is NOT a possible cause of mass extinctions?

• multiple volcanic eruptions

• a rise in global temperatures

• an increase in carbon dioxide and decrease in oxygen

• an asteroid hitting the planet

• a tsunami