Unit 7 Review 𖦹⋆｡°✩

Question 1

African elephants, Loxodonta africana, are often hunted illegally for their tusks. Both male and female elephants have tusks, although the tusks are much larger in the males. Researchers have followed the elephant population in Gorongosa National Park in Mozambique for many years. Figure 1 shows the percent of tuskless female elephants expected in wild populations throughout the species’ range, as well as the percent of tuskless females that survived the hunting between 1977 and 1992 (those over 25 years old) and the percent of female elephants born after 1992 without tusks in the park. The data are based on 200 known female elephants in the park. Which of the following best describes the process responsible for the change in the percent of tuskless female elephants in the Gorongosa National Park population shown in Figure 1 ?

Answer 1

A. Human hunting of elephants with tusks between 1977 and 1992.

B. Sexual selection for females without tusks between 1977 and 1992.

C. Tusklessness in female elephants is a dominant trait that is only expressed in females.

D. After 1992, female elephants from neighboring populations merged, with the population in the park adding more tuskless individuals to the population.

Question 2

✩CORRECT ANSWER FOR 7.1, 1✩

Answer 2

A

Question 3

Scientists investigated the role that beak depth plays in the ability of one species of seed-eating finch to reproduce. The scientists calculated the average beak depth of finches in mating pairs and then observed whether or not the pairs produced at least one offspring that survived to the next season. The data are represented in Figure 1. Based on the data in Figure 1, which of the following best describes the concept illustrated?

Answer 3

A. Parental pairs with a specific beak depth had the highest reproductive fitness.

B. Parental pairs with a specific beak depth ate the most nutritious seeds.

C. Finches with a certain beak depth rarely find mates.

D. Increasing average beak depth results in increasing finch fitness.

Question 4

✩CORRECT ANSWER FOR 7.1, 2✩

Answer 4

A

Question 5

Staphylococcus aureus is a pathogenic bacterium that can infect a wide range of host species, including humans. S. aureus has a particular protein that binds with hemoglobin from the host organism. Hemoglobin is the iron-containing protein used to transport oxygen in the blood. Since iron is important for growth, S. aureus have evolved the ability to absorb the iron from the host’s hemoglobin. Different S. aureus strains preferentially infect different hosts and have different amino acid sequences at their hemoglobin-binding domains (Table 1; letters indicate different amino acids). In an experiment, different S. aureus strains were mixed with hemoglobin from macaque monkeys and their binding ability was measured (Figure 1). The differences in amino acid sequences contributed to the differential binding abilities observed. Which of the following processes is most consistent with the differences in the amino acid sequences listed in Table 1 ?

Answer 5

A. Each host transcribes and translates this gene differently.

B. S. aureus develops a mutualistic relationship with each host species.

C. Changes in amino acid sequence are unrelated to protein function.

D. Each strain is best adapted to a specific host species.

Question 6

✩CORRECT ANSWER FOR 7.1, 3✩

Answer 6

D

Question 7

A current challenge for doctors involves the bacterial strain Clostridioides difficile, which no longer responds to traditional antibiotic treatments. Which of the following best explains why this particular strain of bacteria is resistant to antibiotic treatment?

Answer 7

A. Mutations creating new alleles occur more frequently in this species of bacteria than in other species.

B. The bacteria have high genetic variability and high reproductive rates.

C. Crossing over during meiosis increased genetic variability in the bacteria.

D. The bacteria are able to recognize and destroy the antibiotics by breaking them down extracellularly.

Question 8

✩CORRECT ANSWER FOR 7.2, 1✩

Answer 8

B

Question 9

The bird, Parus major, is commonly found in man-made habitats. During the summer these birds primarily feed on insects, and in the winter, when insects are scarce, they forage in gardens and bird feeders for seeds, nuts, and berries. Recently, climate change has led to a decrease in food available from gardens, and scientists have observed that the average beak length of the birds has increased. Which of the following best explains the directional shift in beak length in these birds?

Answer 9

A. Longer beaks allow the birds to better fend off predators.

B. Longer beaks increase the fitness of the birds in wild habitats.

C. Longer beaks allow the birds to better access seeds in bird feeders.

D. Longer beaks decrease the fitness of the birds in wild habitats.

Question 10

✩CORRECT ANSWER FOR 7.2, 2✩

Answer 10

C

Question 11

✩CORRECT ANSWER FOR 7.2, 3✩
… short answer question

Question 12

Climate change is disrupting the length of winter in various ecosystems, resulting in less snowfall and milder winters. Scientists in Finland have been observing the tawny owl, a fairly large owl species that is commonly found in woodlands across much of Europe and Asia. Typically, the feathers of the upper body are either brown (BB) or gray (bb). Scientists studying tawny owls in Finland have found that the percentage of tawny owls that have brown feathers has increased over the past 28 years. Which of the following best explains why the brown-feathered phenotype in tawny owls has increased over the past 28 years?

Answer 12

A. Since the brown genotype is dominant, it will eventually eliminate the recessive gray genotype from the population.

B. Darker feather color in tawny owls makes them less visible to predators as they sit in the trees.

C. With milder winters, the advantage of gray feathers that blend into a snowy environment has decreased.

D. The directional selection toward a darker phenotype is random and likely due to a bottleneck event.

Question 13

✩CORRECT ANSWER FOR 7.2, 4✩

Answer 13

C

Question 14

Two species of fish that live in extremely cold environments produce near-identical antifreeze glycoproteins, called AFGPs. Scientists have determined the origins of the AFGP gene in both species. Selected characteristics of the two fish species are provided in Table 1. Based on the information in Table 1, which of the following statements best describes the production of nearly identical AFGPs in these two species of fish?

Answer 14

A. The fish eat the same type of food, which resulted in the evolution of similar digestive proteins.

B. The fish live in environments with similar selective pressures, and those that produce AFGPs are better able to survive.

C. The Antarctic fish species evolved into a separate species after being geographically isolated from the Arctic population because of commercial fishing.

D. The production of similar AFGPs was due to random splicing of exons in both species.

Question 15

✩CORRECT ANSWER FOR 7.3, 1✩

Answer 15

B

Question 16

Over many years of a breeding program, a zoo has an established population of foxes that is well adapted for living in captivity. A representative sample of wild foxes from the neighboring forest was used to start the zoo population. A study was conducted to compare the behavior of the zoo fox population with the wild fox population in the neighboring forest. The behaviors of equal numbers of foxes from each population were assessed. Each fox’s behavior was scored on a continuum from docile to aggressive based on its interaction with a trained behaviorist. The data is shown in Figure 1. The phenotypic variation in behavior between the two populations can best be described as resulting from

Answer 16

A. sexual selection

B. natural selection

C. artificial selection

D. genetic drift

Question 17

✩CORRECT ANSWER FOR 7.3, 2✩

Answer 17

C

Question 18

Table 1 shows a trend of increasing milk yield for cows. Part of the increase in milk production can be attributed to improved nutrition and health protocols for dairy cows. Based on the information provided, which of the following best describes the source of the rapid increase in milk production from 1976 to 2015 ?

Answer 18

A. From the 1970s to the early 2000s, dairy cows were not used for beef production.

B. Starting in the 1970s, farmers increased the selective breeding of cows and bulls for offspring that produced more milk.

C. Reproduction rates in cows and bulls increased significantly in the 1970s.

D. Cows were healthier after the 1970s, so they lived longer and produced more milk during their lifetime.

Question 19

✩CORRECT ANSWER FOR 7.3, 3✩

Answer 19

B

Question 20

In humans, one allele of the APOE gene, called APOE-e2, can result in a high tolerance of cholesterol. Cholesterol is a vital substance for humans but may lead to heart disease in an older adult with a history of high cholesterol diets. High cholesterol diets are becoming more prevalent in the United States. Currently only about 2% of humans carry the APOE-e2 allele. Which of the following states a valid null hypothesis about the future distribution of APOE alleles in future generations in the United States?

Answer 20

A. The APOE-e2 allele was the result of chance mutations so it is not possible to predict how its frequency will change in the future.

B. As high cholesterol diets become more common in the United States, individuals with the APOE-e2 allele will have a better survival rate from heart disease than those without the allele, so the allele will increase in frequency.

C. The low frequency of the APOE-e2
allele indicates it is probably a recessive allele, so it will become less frequent as the dominant allele becomes more frequent.

D. The variant protects an individual from a condition that is only common among humans beyond reproductive age, so the frequency of the allele will likely not change much in the future because it is not influenced by natural selection.

Question 21

✩CORRECT ANSWER FOR 7.4, 1✩

Answer 21

D

Question 22

Students observed the distribution of different color phenotypes in northern ravine salamanders (Plethodon electromorphus) before and after a spring flood. The data are shown in Table 1. Which of the following is an appropriate null hypothesis regarding the phenotypic frequencies of this population of salamanders before and after the flood?

Answer 22

A. More black salamanders survived because they could better hide from predators on the dark muddy soil, so the frequency of the black phenotype significantly increased in the population after the flood.

B. Fewer light-brown salamanders survived because they had a reduced chance of finding mates due to the high water levels, so the frequency of the light-brown phenotype in the population decreased after the flood.

C. More dark-brown salamanders migrated to a new, drier area because of the flood and fewer of them remained in the original habitat, so the frequency of dark-brown salamander significantly decreased in the population after the flood.

D. The proportions of black, dark-brown, and light-brown salamanders before and after the flood are not significantly different, and any observed differences are due to random chance.

Question 23

✩CORRECT ANSWER FOR 7.4, 2✩

Answer 23

D

Question 24

The California newt, Taricha torosa, lives in the coastal areas around Los Angeles. Which of the following is a valid null hypothesis relating fitness to survival of a bottleneck event in a coastal area where a small, isolated population of California newts resides?

Answer 24

A. Only those salamanders with the lowest evolutionary fitness will be eliminated by the bottleneck effect, lowering the allelic frequencies of their traits.

B. Only those salamanders with the highest evolutionary fitness will survive the bottleneck event, raising the allelic frequencies of their traits.

C. Surviving the bottleneck event will be random, so any change in the allelic frequencies of the salamander population is not attributed to fitness.

D. Surviving the bottleneck event will be random, so there will be no changes to the allelic frequencies due to the bottleneck event.

Question 25

✩CORRECT ANSWER FOR 7.4, 3✩

Answer 25

C

Question 26

Students analyzed several photosynthetic eukaryotic organisms in the laboratory to determine their phylogenetic relationships. The organisms were Spirogyra (a green alga), a moss, a spruce tree, and an apple tree. Table 1 compares several characteristics in the organisms (+ indicates the trait is present, - indicates the trait is absent). Which of the following rows of data listed in table 1 best supports the possibility of a common ancestor for the organisms listed there?

Answer 26

A. Vascular tissue

B. Seeds enclosed in fruit

C. Cell wall composed of cellulose

D. Flagellated sperm cells

Question 27

✩CORRECT ANSWER FOR 7.6, 1✩

Answer 27

C

Question 28

Researchers studying the evolutionary relationships of three species of snails collected the data shown in Table 1. Which of the following data sets is most likely to provide reliable information about the evolutionary relationships among these three snail species?

Answer 28

A. Shell composition and shell orientation

B. Trophic level and DNA analysis

C. Location of fossils and shell orientation

D. Shell composition and location of fossils

Question 29

✩CORRECT ANSWER FOR 7.6, 2✩

Answer 29

C

Question 30

Hemoglobin is a highly conserved protein used by all mammals to transport oxygen. Table 1 was constructed by comparing the amino acid sequence in the hemoglobin molecules from five different mammal species. Which of the following best describes the importance of the number of amino acid differences indicated in Table 1 ?

Answer 30

A. They reflect the different environments where the organisms were captured.

B. They reflect the number of base pair changes in the DNA.

C. They reflect random changes due to translation errors.

D. They reflect the number of oxygen molecules each hemoglobin molecule carries.

Question 31

✩CORRECT ANSWER FOR 7.6, 3✩

Answer 31

B

Question 32

Researchers observed selected internal structures of four different microscopic organisms as part of a larger study on the divergence between eukaryotes and prokaryotes. Their observations are recorded in Figure 1. Which organism would the researchers most likely predict to be the most distantly related to eukaryotes?

Answer 32

A. Organism I

B. Organism II

C. Organism III

D. Organism IV

Question 33

✩CORRECT ANSWER FOR 7.7, 1✩

Answer 33

A

Question 34

Figure 1 illustrates a process that occurs in a certain group of organisms. Which of the following best predicts the importance of this process?

Answer 34

A. This process is common to all members of Eukarya and allows noncoding regions of RNA to be removed so that proteins with the correct amino acid sequence are produced.

B. This process is common to all members of Archaea and allows these organisms to survive harsh environments.

C. This process is common to all organisms and is a conserved DNA repair mechanism.

D. This process is common to vertebrates and allows the production of large and complicated proteins.

Question 35

✩CORRECT ANSWER FOR 7.7, 2✩

Answer 35

A

Question 36

Transposable elements are significant features in the genomes of almost all eukaryotic organisms. The accumulation of these elements in various species can help determine their relatedness. Table 1 indicates the presence (+) or absence (-) of 5 segments of DNA that have been moved by transposition (transposons) in 6 primate species. Which of the following best predicts how phylogenetic relationships might be revised if transposon 1 was not found in chimpanzees?

Answer 36

A. Bonobos would be more closely related to humans than to chimpanzees.

B. Chimpanzees would be more closely related to humans than to bonobos.

C. Orangutans would be more closely related to humans than to chimpanzees.

D. Chimpanzees would be more closely related to gibbons than to gorillas.

Question 37

✩CORRECT ANSWER FOR 7.7, 3✩

Answer 37

B

Question 38

Researchers examined the ability of cultures of the bacterium Pseudomonas aeruginosa to adapt to the antibiotics ceftazidime and avibactam when they are administered together. The researchers grew four replicate cultures in growth medium with no antibiotics added (control) and four additional replicate cultures in the same growth medium with added ceftazidime and avibactam. At the conclusion of the experiment, samples of the replicates exposed to the antibiotics were removed and their genomes were sequenced. All of the antibiotic-resistant mutants were missing three genes (hmgA, galU, mexXY). It is known that one of these three genes makes wild-type P. aeruginosa susceptible to the two antibiotics. However, the researchers do not know which gene it is. Which of the following experiments would specifically determine which gene is responsible for ceftazidime-avibactam sensitivity in P. aeruginosa ?

Answer 38

A. Clone the three deleted genes from a wild-type P. aeruginosa strain, and insert these sequences into the mutant bacterial strains to restore sensitivity to ceftazidime-avibactam.

B. Delete genes that are homologous to the three deleted genes in other bacterial species, and determine if doing so also confers ceftazidime-avibactam resistance in those bacteria.

C. Perform gene knockout (targeted mutation) of either the hmgA, galU, or mexXY gene on separate cultures of the wild-type P. aeruginosa. For each individual mutant, determine whether or not ceftazidime-avibactam resistance has occurred.

D. Perform gene knockout (targeted mutation) of both the hmgA and galU genes of the wild-type P. aeruginosa in a single culture, and then determine if ceftazidime-avibactam resistance has occurred in the mutant strain.

Question 39

✩CORRECT ANSWER FOR 7.8, 1✩

Answer 39

C

Question 40

Low doses of antibiotics are often added to livestock feed to increase production. Studies have shown that bacterial populations constantly exposed to the sublethal doses can evolve resistance to the antibiotics. A research group claimed that when a population of bacteria are constantly exposed to sublethal doses of streptomycin, their fitness declines due to the increased energy requirements for survival in the presence of the antibiotic. For subsequent studies, the researchers wish to determine whether adding a low, sublethal dose of an additional antibiotic causes further decline in the fitness of the bacteria. Which of the following best represents the next step the researchers should take with respect to experimental design?

Answer 40

A. Group 1: high dose of streptomycin
low dose of additional antibiotic
Group 2: low dose of streptomycin
high dose of additional antibiotic

B. Group 1: low dose of streptomycin
no dose of additional antibiotic
Group 2: low dose of streptomycin
low dose of additional antibiotic

C. Group 1: no dose of streptomycin
no dose of additional antibiotic
Group 2: low dose of streptomycin
low dose of additional antibiotic

D. Group 1: low dose of streptomycin
low dose of additional antibiotic
Group 2: high dose of streptomycin
high dose of additional antibiotic

Question 41

✩CORRECT ANSWER FOR 7.8, 2✩

Answer 41

B

Question 42

Staphylococcus aureus is a pathogenic bacterium that can infect a wide range of host species, including humans. S. aureus has a particular protein that binds with hemoglobin from the host organism. Hemoglobin is the iron-containing protein used to transport oxygen in the blood. Since iron is important for growth, S. aureus have evolved the ability to absorb the iron from the host’s hemoglobin. Different S. aureus strains preferentially infect different hosts and have different amino acid sequences at their hemoglobin-binding domains (Table 1; letters indicate different amino acids). In an experiment, different S. aureus strains were mixed with hemoglobin from macaque monkeys and their binding ability was measured (Figure 1). The differences in amino acid sequences contributed to the differential binding abilities observed. Which of the following experiments would be most appropriate to determine whether populations of S. aureus are continuously adapting in order to obtain iron from hosts more effectively?

Answer 42

A. Grow S. aureus in media with macaque hemoglobin and abundant free iron. Record bacterial growth over time and compare it to growth of the original population.

B. Culture S. aureus bacteria with hemoglobin from a mixture of host species. Then transfer the bacteria to media with a known effective antibiotic and record bacterial growth.

C. Sequence the genes of different S. aureus strains and construct a cladogram representing their relatedness.

D. Culture S. aureus bacteria with hemoglobin from a novel host species as the only source of iron for many generations, then compare protein structure from bacteria in this culture with bacteria from the original culture.

Question 43

✩CORRECT ANSWER FOR 7.8, 3✩

Answer 43

D

Question 44

✩WAITING ON SPECIATION QUIZ RESULTS✩