Unit 4 Quiz

1. Although it is incomplete, the fossil record provides scientists with a great deal of information about species that have lived on Earth throughout its history. Which of the following statements does the fossil record support?

• A - All organisms that have ever existed on Earth continue to live on Earth today.

• B - Earth’s organisms have remained unchanged throughout its history.

• C - Dinosaurs are the only types of organisms that have become extinct.

• D - Not all species that are alive today were alive in the past.

2. What can you infer about how the canyon looked a thousand years ago?

• A- The canyon was just as deep but had no water.

• B - The canyon was not as deep as it is today.

• C - The canyon was much deeper than it is today.

• D - The canyon looked exactly like it does today.

3. How does the use of radioactive dating help scientists develop the evolutionary tree of fossilized organisms?

• A - It tells when a fossilized organism was born.

• B - It tells where a fossilized organism was found.

• C - It tells the approximate age of a fossilized organism.

• D - It tells how quickly new species evolved from fossilized organisms.

4. Fossils are the preserved remains of organisms that lived long ago. According to the law of superposition, the rock layers that contain fossils should be far below Earth’s surface. Which answer best explains why fossils are sometimes found at or near the surface?

• A - Fossils are moved to the surface by other organisms.

• B - Fossils are less dense than rock, so they rise to the surface.

• C - Sedimentary rock layers are relatively soft, and new fossils sink through upper layers into older, deeper layers.

• D - Some rock layers with fossils have been exposed because of different processes, such as faulting, folding, and weathering.

5. The rock layers that make up the Grand Canyon range in age from 2 billion to 230 million years. What would a scientist need in order to compare the ages of rocks from two different parts of the canyon?

• A - the location of each rock

• B - the amounts of radioactive elements in each rock

• C - the size of the crystals that make up each rock

• D - the size and hardness of each rock

Imagine two rocks. One rock contains nearly all of its original potassium-40. In a second rock, most of the potassium-40 has decayed. Which statement about the first rock is true?

• A - It is a metamorphic rock.

• B - It is harder than the second rock.

• C - It is younger than the second rock.

• D - It is older than the second rock.

7. What does the term half-life mean when using radioactive dating to determine the age of fossils?

• A - Half-life is used to describe half the amount of time it takes for a fossil to become radioactive.

• B - Half-life is used to describe half the amount of time it takes for an organism to fossilize in radioactive sediment.

• C - Half-life is used to describe the amount of time it takes for half of a radioactive substance to decay.

• D - Half-life is used to describe the amount of geologic time represented by half of a horizontal layer in radioactive sediment.

8. Scientists find a fossil of a fish on top of a mountain. What kind of evidence does the fossil provide scientists about the way this area might have changed over time?

• A - It shows that the mountain may have once been under water and raised up by natural processes.

• B - It shows that oceans can change quickly and become land.

• C - It shows that the animals found on the mountain today evolved from fish.

• D - It shows that fish were once able to live without water.

9. Berta knows that sharks have been around for millions of years. She has found a fossil of a shark tooth while taking a core sample of the ocean floor.

Assuming that the layers of sediment in the core sample were undisturbed, what is the best way to determine the age of the shark tooth fossil?

• A - Compare it to the teeth of modern sharks to see how different it is.

• B - Test the hardness of the fossil to determine how long it has been fossilizing.

• C - Examine the tooth’s surface to study microscopic evidence of the fossil’s age.

• D - Determine the age of the layer of sediment in which the fossil was found relative to other layers above and below it.