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2. Which of the following statements can be associated with the concept of the “unity of life” and which can be associated with the concept of the “diversity of life”? Note that both concepts may apply to some statements.
The amino acid sequences of cytochrome c (an enzyme in mitochondria) in humans and chimpanzees differ by one amino acid.
If the gene for human insulin is inserted into bacteria, the bacteria can make human insulin.
Medium ground finches (Geospiza fortis) have beaks that are similar in shape but smaller than those of large ground finches (Geospiza magnirostris).
The basic forelimb structure of horses and moles is similar.
Scientists interested in curing human cancer may study cell division in yeasts.
Answer: This question is designed to make students think about the apparent contradiction that evolution can explain both the unity and diversity of life. Options b, d, and e are clearly related to the “unity of life”: These answers all show similarities among different species. Students may disagree on whether option a is associated with “unity” (there is lots of similarity) or “diversity” (there is one difference) and should be able to make good arguments for both. In option c, the similarity in shape would relate to the “unity of life,” but the difference in shape would relate to the “diversity of life.”

3. Imagine two species that are thought to have a recent common ancestor
Imagine two species that are thought to have a recent common ancestor. If this idea is correct, these two species most likely have ______.
no morphological similarities
few biochemical similarities
several homologous structures
a shared habitat
Answer: c 3

4. Imagine two species that are thought to have a recent common ancestor
Imagine two species that are thought to have a recent common ancestor. If this idea is correct, these two species most likely have ______.
no morphological similarities
few biochemical similarities
several homologous structures
a shared habitat 4

5. You find a section of sedimentary rock in which the strata and some fossils have been exposed. You notice that a clam fossil is in deeper strata than a fish fossil. Using relative dating, which fossil is most likely older?
clam
fish
not enough data to answer
Answer: The answer technically should be a, but students could argue that c or even b is correct, since tectonic activity could have altered these strata. 5

6. You find a section of sedimentary rock in which the strata and some fossils have been exposed. You notice that a clam fossil is in deeper strata than a fish fossil. Using relative dating, which fossil is most likely older?
clam
fish
not enough data to answer 6

7. You discover fish living in a cave with no natural light
You discover fish living in a cave with no natural light. The fish have no eyes, but they do have eye sockets. Using a Lamarckian thought process, which of the following would be the reason for this?
The fish were in a dark environment and therefore didn’t need eyes. Over time, they used their developmental energy for other more useful features, so because they didn’t use their eyes, they lost them.
The fish never had eyes but are slowly evolving to have them because they will need them someday.
Originally, all fish in the population had eyes and could see. However, in the dark, there was no longer selection for sight, and eyes were eventually lost due to random mutations.
Answer: a. Lamarck believed in the concept of use and disuse. 7

8. You discover fish living in a cave with no natural light
You discover fish living in a cave with no natural light. The fish have no eyes, but they do have eye sockets. Using a Darwinian thought process, which of the following would be the reason for this?
The fish were in a dark environment and therefore didn’t need eyes. Over time, they used their developmental energy for other more useful features, so because they didn’t use their eyes, they lost them.
The fish never had eyes but are slowly evolving to have them because they might need them in the future.
Originally, all fish in the population had eyes and could see. However, in the dark, there was no longer selection for sight, and eyes were eventually lost due to random mutations.
Answer: c. This illustrates that selection was occurring and that it was occurring at a population level. 8

9. Using the Galápagos finches example from the book, which of the following best explains the Darwinian reason why the insect-eating finch has such a long, narrow beak?
Variation existed in the finch population. Those that naturally had longer, narrower beaks could reach their food more easily, allowing finches with these features to survive and reproduce more often than those that did not.
Every day, finches who needed to eat insects would squeeze their beaks into tiny holes to reach insects, eventually changing the shape of their beaks; this shape was then passed on to future generations.
Those with longer, narrower beaks carried the dominant gene for that trait, causing it to become more prevalent.
Answer: a. Those with the best fit to the environment, those with the long, narrow beak, were able to eat and survive and therefore had a greater chance of passing on their genes. 9

10. MRSA infections are occurring at alarming rates
MRSA infections are occurring at alarming rates. One reason for this could be that people do not finish their antibiotics. Which of the following is the most likely reason that this could lead to something like MRSA?
Antibiotics take some time to start working, giving the bacteria time to mount defenses against the antibiotics over a few days.
Because antibiotics are often taken when there is no bacterial infection, the antibiotics aren’t using their medicinal/antibacterial properties and are losing them.
The first few days of antibiotics kill off the susceptible bacteria, making people feel better. Then, when people stop taking the antibiotics, the resistant bacteria that survived reproduce to create a more resistant population.
Answer: c. The antibiotics originally killed the weaker bacteria, leaving only the strong ones to breed with one another, changing the population into a more antibiotic-resistant group. 10

11. Plants in “Mediterranean” ecosystems have similar adaptations for surviving hot, dry summers and fire. Given that these ecosystems are presently found in southern Europe, California, Chile, South Africa, and southern Australia, which of the following best explains the origin of these adaptations?
These adaptations likely arose in a common ancestor on Pangea, and continental drift later moved these drought- and fire-adapted plants to their present locations.
These plants likely share a recent common ancestor and have been subjected to the same selective pressures.
Although these plants likely do not share a recent common ancestor, they have been subjected to the same selective pressures.
Answer: c. These regions are widely spaced around the Earth, making it unlikely that the plants all descended from the same recent common ancestor. It is more likely that the common environmental factors (drought and fire) selected for the same types of adaptations (making this a case of evolutionary convergence). 11

12. A number of scientists influenced Darwin’s thinking about evolution
A number of scientists influenced Darwin’s thinking about evolution. Which of the following scientists had proposed that the geological processes of the past (e.g., rivers forming valleys over time) were still in operation?
Cuvier
Lyell
Linnaeus
Malthus
Wallace
Answer: b. It was Lyell’s book Principles of Geology that Darwin read during his voyage on the Beagle. 12

13. On Darwin’s tour of South America, which of the following facts became clear to him?
The Earth must be very old.
Regardless of habitat, living South American organisms resembled each other more than they did the organisms of England.
South American fossils resembled living South American organisms.
The Galápagos Islands were colonized from the continental mainland.
all of the above
Answer: e

14. The Lamarckian and Darwinian views of evolution share all of the following ideas except
life evolves over time.
the environment plays a role in evolution.
inheritance from generation to generation is a key factor in evolution.
organisms have an innate drive to become more complex.
Answer: d

15. There are many categories of evidence that support evolution by natural selection. Which type of evidence would have been unfamiliar to Darwin during his life?
fossils
breeding (artificial selection)
DNA and genetics
biogeography
homology
Answer: c. Darwin may not have known the terms “biogeography or “homology,” but he would have been conversant with the topics they represent.

16. Artificial selection (breeding) was a very important factor in the development of Darwin’s ideas on natural selection. In which of the following respects is artificial selection distinct from natural selection?
Artificial selection does not require heritable variation.
Artificial selection does not result in evolutionary change.
Artificial selection does not rely exclusively on the environment to determine relative survival and reproduction rates.
Artificial selection does not result in an increase in favorable characteristics.
Answer: c. This question is designed to highlight the overall similarities of the two processes. The real difference is that with artificial selection, it is humans, directly or indirectly, who choose relative survival and reproduction rates.

17. Under which of the following conditions could evolution by natural selection not occur?
no genetic variation in a population
very long generation times
very short generation times
very stable environment
no predation
Answer: a. Genetic variation is a fundamental requirement for natural selection to work. Generation time is not a factor. Many students think that a changing environment or some predation pressure are required, but they are not. There must be some environmental constraint, but not any particular constraint.

18. Considering how MRSA arose, what is a reasonable prediction for what will happen as the new antibiotic “teixobactin” is applied to MRSA?
Some MRSA cells will be naturally resistant to teixobactin and will become more prevalent due to selection.
Some MRSA cells will become resistant by evolving new genes in direct response to teixobactin.
MRSA will be completely eradicated because teixobactin is a new antibiotic.
A new bacteria will evolve to take the place of MRSA.
Answer: a

19. Should bat wings be considered homologous to whale flippers
Should bat wings be considered homologous to whale flippers? Which of the following is the best answer and argument?
Yes. They are both limbs and are both used for locomotion.
No. They have very different uses—flight versus swimming.
Yes. They have similar bone structure inherited from a common ancestor.
No. There is no common ancestor of bats and whales.
Answer: c. This question highlights the definition of homology and uncovers some common misconceptions about homology.

20. Suppose two species have a similar feature, and you are trying to decide whether the feature is homologous or convergent. What is the best strategy to use?
Determine if the feature is shared with a third species.
Determine if their common ancestor also had the feature.
Determine if the feature is used for the same purpose in the two species.
Determine if the feature is vestigial.
Determine if the two species also share other features.
Answer: b. Ancestry is the key to homology.

21. Adaptations can be thought of as features that increase an organism’s ability to survive and reproduce in a given environment. Which of the following factors can be considered adaptations?
avoiding predators
using available shelter
attracting mates
metabolic efficiency
all of the above
Answer: e. This is a simple question to elicit discussion on the many types of adaptations. This can be followed up with open discussion to add to the list.