Earth’s History- Geologic Time Scale Test
Multiple Choice:
Write the letter of the correct answer
1. What are fossils?
a. molds and casts of organisms that live today
b. drawings of ancient animals and other organisms
c. footprints or burrows of small animals that live today
d. the preserved remains or traces of organisms that lived in the past
2. What has the study of fossils allowed scientists to do?
a. describe past environments and the history of life
b. study present ocean temperatures at different depths
c. analyze the chemical composition of sedimentary rocks and minerals
d. predict which organisms will become extinct in the future
3. All of the following show examples of relative ages EXCEPT:
a. Melissa is much older than Scott
b. Rachel is younger then Wes but the same age as Donna
c. Sara is several years younger then Anthony
d. Tommy is 10 years old.
4. Geologists use radioactive dating to
a. determine the relative ages of rock layers.
b. tell the difference between molds and casts.
c. tell where one soil horizon ends and the next one begins.
d. determine the absolute ages of rocks.
5. A type of organism that no longer exists on Earth is said to be
a. fossilized.
c. extinct.
b. sedimentary.
d. petrified.
6. What principle states that the geologic processes that change Earth today also changed Earth
in the past?
a. uniformitarianism
c. superposition
b. evolution
d. erosion
7. What is the age of an intrusion of igneous rock in relation to the sedimentary rock layers through which it
passes?
a. always older
c. always younger
b. sometimes younger, sometimes older
d. the same age as the other rock layers
8. Trilobites lived approximately 500 million years ago. If a fossilized tooth is found in a rock layer above
trilobite fossils, which of the following is true?
a. The absolute age of the trilobite tooth is 240 million years old.
b. The fossilized tooth is from a trilobite.
c. The relative age of the fossilized tooth is older than the trilobite fossil.
d. The relative age of the fossilized tooth is younger than the trilobite fossil.
9. The fossil record shows that life on Earth has changed over time. For example, paleontologists have
found that older rocks contain fossils of _______________________.
a. only organisms that are alive today.
b. organisms that are more complex than those alive today.
c. simpler organisms.
d. both simple and complex organisms.
Completion
Fill in the blank to complete each statement.
10. An extrusion occurs when ____________ hardens on Earth’s surface.
11. Scientists who study fossils are called. ___________
12. A(n) ____________________ fossil forms when dissolved minerals replace the remains of an organism
and then harden to form rock.
13. A(n) ____________________ is a gap in the geologic record where some rock layers have been lost
because of erosion.
14. Potassium-40 is useful for dating very old rocks because it has a(n) ____________________ of 1.3
billion years.
Earth’s surface has constantly changed over billions of years. Continents that were once joined have
been separated and then joined again. Rocks that were once under the ocean have been pushed up
and today are dry land. New layers of rock have formed on top of older layers and then have been
covered by even newer layers. Rocks on land have been pushed under the ocean. By studying fossils,
scientists can make inferences about Earth’s history.
Imagine that you are studying the fossil data describe below. For each piece of evidence, write an
inference you can make about Earth’s history or the age of a rock layer.
Evidence
Fossil A is found in a lower layer of rock
than Fossil B.
Fossils of a kind of organism that lived for
only a short time 400 million years ago are
found at different locations around the
world.
Inference
15.
16.
17. In the picture above, put layers
A-E in order from oldest to youngest.
18. In the picture above, what is
letter A an example of
How many layers of rock are younger in age than layer “C”?
Support your answer with 3 pieces of evidence and include the principles of relative dating.
Claim: Your claim should be the answer to the question above.
Evidence: Is Layer “M” older or younger than layer “C”?
Reasoning: What geologic principle did you use to come up with your answer? Explain.
Evidence: Is the fault line “H” younger or older than layer “C”?
Reasoning: What geologic principle did you use to come up with your answer? Explain.
Evidence: Is intrusion “A” younger or older than layer “M”?
Reasoning: What geologic principle did you use to come up with your answer? Explain.
Re-state Claim: Write a concluding sentence that includes your original claim.