Name ______________________________ Class ___________________ Date __________________
Skills Worksheet
Critical Thinking – Unit 11A – CH 8
ANALOGIES
In the space provided, write the letter of the pair of terms or phrases that best
complete the analogy shown. An analogy is a relationship between two pairs of
words or phrases written as a : b :: c : d. The symbol : is read is to, and the symbol
:: is read as.
_____ 1. relative age : absolute age ::
a. younger : older
b. numeric age : older
c. older : numeric age
d. older : younger
_____ 6. geology : paleontology ::
a. fossils : rocks
b. month : millennium
c. small : large
d. rocks : fossils
_____ 2. nonconformity :
unconformity ::
a. set : subset
b. subset : set
c. break : layer
d. break : fast
_____ 7. trace fossil : tracks ::
a. advance : defeat
b. find : encyclopedia
c. finding : classifying
d. index fossil : dating
_____ 3. varve : sedimentary rock ::
a. annual : biannual
b. tree ring : tree
c. rock : plant
d. night : day
_____ 8. geology :
uniformitarianism ::
a. economics : communism
b. biology : evolution
c. physics : astrophysics
d. subset : set
_____ 4. uranium-238 : billion ::
a. week : month
b. thousand : million
c. carbon-14 : thousand
d. isotope : element
_____ 9. fault : intrusion ::
a. summer : winter
b. crack : layer
c. blame : annoyance
d. crack : magma
_____ 5. atomic number : mass
number ::
a. protons : neutrons
b. protons : nucleus
c. neutrons : nucleus
d. neutrons : protons
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Holt McDougal Earth Science
3
The Rock Record
Name ______________________________ Class ___________________ Date __________________
Critical Thinking continued
INTERPRETING OBSERVATIONS
Read the following passage, and answer the questions below.
Hominids are extinct, human-like creatures that pre-date modern humans. Some of
the oldest known hominid fossils have been found at Olduvai Gorge in Tanzania.
The gorge is a 15-mile long eroded canyon, 328 feet deep, with undisturbed
stratified layers of sediment and rock that geologists can date back nearly
2 million years. The remains of at least 48 hominids have been found at Olduvai
Gorge.
But 30 miles south of Olduvai Gorge, at Laetoli, hominid bones have been
found that date to about 3.5 million years ago, and 59 footprints preserved in a
volcanic ash layer have been found nearby. From the footprints, scientists have
deduced that the hominids walked upright like modern humans and that the adults
were under five feet tall.
10. Could scientists use carbon dating to determine the age of early hominids?
Explain.
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11. How would scientists have dated fossil bones found in Olduvai Gorge?
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12. What method of dating fossil bones did scientists most likely use to discover
that the bones at Laetoli were about 3.5 million years old?
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13. What is the term for the preserved footprints the paleontologists found? How
do you think scientists determined the height of the hominids using the
footprints?
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Holt McDougal Earth Science
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The Rock Record
Name ______________________________ Class ___________________ Date __________________
Critical Thinking continued
AGREE OR DISAGREE
Agree or disagree with the following statements, and support your answers.
14. A sedimentary rock layer is always younger if it is above another sedimentary
rock layer.
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15. Studying rates of erosion is a dependable method of dating the Grand Canyon.
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16. Fossils can always be dated by the rock strata in which they are found.
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17. Uranium-238 would be useful in dating a geologic sample that is
approximately 20 million to 50 million years old.
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Holt McDougal Earth Science
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The Rock Record
Name ______________________________ Class ___________________ Date __________________
Critical Thinking continued
REFINING CONCEPTS
The statements below challenge you to refine your understanding of concepts
covered in the chapter. Think carefully, and answer the questions that follow.
18. At the time James Hutton developed his theory of uniformitarianism, many
people thought that Earth was about 6,000 years old. Why do most scientists
today believe that Earth is much older—more than 4.5 billion years old?
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19. Erosion and deposition play a part in all unconformities. Describe an
unconformity, and give an example of how erosion and deposition are
involved in the formation of an unconformity.
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20. An alpha particle consists of two protons and two neutrons. What is the
relationship between alpha decay and the dating of geologic formations?
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Original content Copyright © Holt McDougal. All rights reserved. Additions and changes to the original content are the responsibility of the instructor.
Holt McDougal Earth Science
6
The Rock Record