1. 23
Broad Patterns of Evolution

2. Which of the following is a rich source for the earliest prokaryote fossils?
sedimentary rock
metamorphic rock
coral reefs
stromatolites
Answer: D. This is a good question for checking to see whether students have read the chapter.
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3. Which of the following is a rich source for the earliest prokaryote fossils?
sedimentary rock
metamorphic rock
coral reefs
stromatolites
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4. Radiometric dating _____.
can be used to directly date fossils in sedimentary rock
relies on the fact that the daughter isotope decays to the parent isotope at a constant rate
allows us to indirectly date fossils up to billions of years old based on minerals in surrounding volcanic strata
works only on rocks younger than 75,000 years
allows us to determine an absolute, errorless date
Answer: C
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5. Radiometric dating _____.
can be used to directly date fossils in sedimentary rock
relies on the fact that the daughter isotope decays to the parent isotope at a constant rate
allows us to indirectly date fossils up to billions of years old based on minerals in surrounding volcanic strata
works only on rocks younger than 75,000 years
allows us to determine an absolute, errorless date
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6. You discover three fossil organisms and want to determine their dates
You discover three fossil organisms and want to determine their dates. You measure the percentage of carbon-14 (half-life of 5,730 years) remaining in the fossils. Which of the following correctly places them in order from oldest to youngest?
A, B, C
B, C, A
C, A, B
A, C, B
Fossil
% 14C A
38.7 B
77.0 C
52.1
Answer: D. This question is aimed at Concept 23.1 and focuses on radiometric dating. It is the first of two questions that might be used together.
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7. You discover three fossil organisms and want to determine their dates
You discover three fossil organisms and want to determine their dates. You measure the percentage of carbon-14 (half-life of 5,730 years) remaining in the fossils. Which of the following correctly places them in order from oldest to youngest?
A, B, C
B, C, A
C, A, B
A, C, B
Fossil
% 14C A
38.7 B
77.0 C
52.1
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8. You discover a series of fossil organisms and want to determine their dates. You decide to use carbon-14 dating (half-life of 5,730 years). Based on the table below, about how old are fossils A and B?
57,300 years
5,730 years
2,865 years
1,432 years
other
Sample
14C to 12C ratio
Normal
1 to 1 million
Fossil A
0.74 to 1 million
Fossil B
0.76 to 1 million
Answer: C. This question is aimed at Concept Students learn how samples are dated using radiometric dating techniques. This question can be altered easily by changing the carbon ratios.
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9. You discover a series of fossil organisms and want to determine their dates. You decide to use carbon-14 dating (half-life of 5,730 years). Based on the table below, about how old are fossils A and B?
57,300 years
5,730 years
2,865 years
1,432 years
other
Sample
14C to 12C ratio
Normal
1 to 1 million
Fossil A
0.74 to 1 million
Fossil B
0.76 to 1 million
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10. When did the first prokaryotes arise, according to the fossil record?
2.5 billion years ago
4 million years ago
3.5 billion years ago
2,000 years ago
Answer: C. The earliest fossils found so far are 3.5 billion years old.
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11. When did the first prokaryotes arise, according to the fossil record?
2.5 billion years ago
4 million years ago
3.5 billion years ago
2,000 years ago
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12. One species of finch colonizes an island and, over a relatively short period of time, speciates into several different finch species. This is an example of
adaptive radiation.
sympatric speciation.
allopatric speciation.
symbiosis.
Answer: A. Adaptive radiation is when one species evolves into several different species over a short period of time.
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13. One species of finch colonizes an island and, over a relatively short period of time, speciates into several different finch species. This is an example of
adaptive radiation.
sympatric speciation.
allopatric speciation.
symbiosis.
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14. Potassium-40 is a commonly used isotope for radiometric dating
Potassium-40 is a commonly used isotope for radiometric dating. It decays to argon-40, with a half-life of 1.3 billion years. A volcanic rock is found to have 1/8 as much potassium-40 as liquid lava. How old is the rock?
162 million years
1.3 billion years
3.9 billion years
10.4 billion years
Answer: C. A = simply 1/8 of 1.3 billion; B = only 1 half-life; C = the correct recognition that 1/8 is three half-lives; D = 8 times 1.3 billion.
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15. Potassium-40 is a commonly used isotope for radiometric dating
Potassium-40 is a commonly used isotope for radiometric dating. It decays to argon-40, with a half-life of 1.3 billion years. A volcanic rock is found to have 1/8 as much potassium-40 as liquid lava. How old is the rock?
162 million years
1.3 billion years
3.9 billion years
10.4 billion years
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16. The Cambrian explosion marks the relatively “sudden” appearance of many animal phyla approximately 542 million years ago. Approximately what percentage of Earth’s history has occurred since the appearance of animals? 1%
13%
50%
87%
Answer: B. This question helps put the enormous amount of pre-Cambrian geologic time into perspective. Graphics like Table 23.1 tend to overemphasize the Phanerozoic.
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17. The Cambrian explosion marks the relatively “sudden” appearance of many animal phyla approximately 542 million years ago. Approximately what percentage of Earth’s history has occurred since the appearance of animals? 1%
13%
50%
87%
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18. Which of the following is a reasonable prediction concerning plate tectonics and continental drift?
Continents should slowly stabilize their current positions.
Continents will stabilize their positions once they are as far apart as possible.
Continents should eventually re-aggregate into a supercontinent before breaking up again.
No new mountain ranges should form.
Answer: C
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19. Which of the following is a reasonable prediction concerning plate tectonics and continental drift?
Continents should slowly stabilize their current positions.
Continents will stabilize their positions once they are as far apart as possible.
Continents should eventually re-aggregate into a supercontinent before breaking up again.
No new mountain ranges should form.
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20. A basic tenet of evolution by natural selection is that species should continually become more fit for their environment. What, then, can account for extinction?
Natural selection temporarily stops working.
New mutations decrease fitness.
The environment changes more rapidly than species can adapt.
Species have fixed life spans.
Answer: C
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21. A basic tenet of evolution by natural selection is that species should continually become more fit for their environment. What, then, can account for extinction?
Natural selection temporarily stops working.
New mutations decrease fitness.
The environment changes more rapidly than species can adapt.
Species have fixed life spans.
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22. When was the largest mass extinction in the history of our planet?
542 million years ago
252 million years ago
65 million years ago
currently ongoing
Answer: B. This was the Permian extinction.
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23. When was the largest mass extinction in the history of our planet?
542 million years ago
252 million years ago
65 million years ago
currently ongoing
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24. The hundreds of varied fruit fly species on the Hawaiian Islands arose through adaptive radiation. Which piece of evidence would best support this claim?
The Hawaiian fruit fly species all physically resemble one another more than they do non-Hawaiian fruit flies.
The Hawaiian fruit fly species are more closely related to each other genetically than they are to non-Hawaiian fruit flies.
The Hawaiian fruit fly species all occupy similar ecological niches.
The Hawaiian fruit fly species are radioactive.
Answer: B. Photos of various Hawaiian fruit flies could be shown here.
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25. The hundreds of varied fruit fly species on the Hawaiian Islands arose through adaptive radiation. Which piece of evidence would best support this claim?
The Hawaiian fruit fly species all physically resemble one another more than they do non-Hawaiian fruit flies.
The Hawaiian fruit fly species are more closely related to each other genetically than they are to non-Hawaiian fruit flies.
The Hawaiian fruit fly species all occupy similar ecological niches.
The Hawaiian fruit fly species are radioactive.
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26. Which statement concerning evolutionary novelties has the least evidence to support it?
New evolutionary structures require new genes.
New evolutionary structures can arise from changes in the expression of existing genes.
Complex structures can evolve in stepwise fashion.
Structures evolved in one context can be co-opted for another function.
Answer: A
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27. Which statement concerning evolutionary novelties has the least evidence to support it?
New evolutionary structures require new genes.
New evolutionary structures can arise from changes in the expression of existing genes.
Complex structures can evolve in stepwise fashion.
Structures evolved in one context can be co-opted for another function.
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28. Which of the following evolutionary novelties is least consistent with being facilitated by a Hox gene?
crustacean feeding appendages
paedomorphosis in salamanders
loss of limbs in snakes
wing number in insects
Answer: B
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29. Which of the following evolutionary novelties is least consistent with being facilitated by a Hox gene?
crustacean feeding appendages
paedomorphosis in salamanders
loss of limbs in snakes
wing number in insects
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30. The gene Pax6 is expressed and required in the developing eye of both molluscs and vertebrates. What is the simplest explanation for this?
Pax6 is a homeotic gene.
Pax6 was independently co-opted into the developing eyes of both molluscs and vertebrates.
Mollusc eyes and vertebrate eyes both evolved from simple photoreceptors present in a common ancestor that used the Pax6 gene.
Mollusc eyes and vertebrate eyes have very similar structure that requires the Pax6 gene.
Answer: C
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31. The gene Pax6 is expressed and required in the developing eye of both molluscs and vertebrates. What is the simplest explanation for this?
Pax6 is a homeotic gene.
Pax6 was independently co-opted into the developing eyes of both molluscs and vertebrates.
Mollusc eyes and vertebrate eyes both evolved from simple photoreceptors present in a common ancestor that used the Pax6 gene.
Mollusc eyes and vertebrate eyes have very similar structure that requires the Pax6 gene.
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