APBIO 7

practice test

A moth's color is controlled by two alleles, G and g, at a single locus. G (gray) is dominant to g (white). A large population of moths was studied, and the frequency of the G allele in the population over time was documented, as shown in the figure below. In 1980 a random sample of 2,000 pupae was collected and moths were allowed to emerge. Assuming that the population was in Hardy-Weinberg equilibrium for the G locus, what percentage of moths in the natural population was white in 1962?

4%

The appearance of a fertile, polyploid individual within a population of diploid organisms is a possible source of a new species. If this individual is capable of reproducing to form a new population, scientists would consider this to be an example of

sympatric speciation

Blue-footed boobies, inhabitants of the Galapagos, mate only after a courtship display unique to the species. Part of the "script" calls for the male to high-step (e), a behavior that calls the female's attention to his bright blue feet. What type of barrier would this be if the female was not attracted to his movements?

Prezygotic

Which is generally considered the most accurate, morphological data or amino acid sequence data?

Amino acid sequence data

We learned in class that the following graph on Russian Silver Foxes was best described as resulting from artificial selection. Which of the following statements would justify that instead of artificial selection the results were due to genetic drift?

These results came from one zoo only.

Which of the following statements are true based upon the phylogenic tree below? Check all that apply.

Coyotes and wolves can switch positions on the tree and the information is the same,

Coyotes and wolves have more similar DNA sequences than wolves and otters.

Snails in the genus Bradybaena approach each other headfirst when they attempt to mate. Once their heads moved slightly past each other, the snails' genitals emerge, and if their shells spiral in the same direction, mating can occur (f). But if a snail attempts to mate with a snail whose shells spirals in the opposite direction (g), the two snails' genital openings (indicated by arrows) will not be aligned, and mating cannot be completed. What type of barrier is this?

Prezygotic

The enzyme lactase aids in the digestion of lactose, a sugar found in the milk of most mammals. In most mammal species, adults do not produce lactase. Continuing to produce lactase into adulthood in people is called lactase persistence. A number of different alleles have been identified that result in lactase persistence. The figure below shows the percentage of people in different geographic areas parts of the Old World that exhibit lactase persistence. Which of the following best explains the distribution of lactase persistence in the areas shown?

Mutations conferring lactase persistence likely arose independently in different geographic areas and offered a selective advantage.

A biologist spent many years researching the rate of evolutionary change in the finch populations of a group of islands. It was determined that the average beak size (both length and mass) of finches in a certain population increased dramatically during an intense drought between 1981 and 1987. During the drought, there was a reduction in the number of plants producing thin-walled seeds. Which of the following procedures was most likely followed to determine the change in beak size?

The beak size in a large number of finches was measured every year from 1981 to 1987.

How does Paul Anderson define evolution?

Changes to the gene pool

In an experiment, 100 mice were released into a field to which no other mice had access. Immediately after their release, a representative sample of mice was captured, their fur color was recorded, and they were returned to the field. After twenty years, a representative sample of mice was captured and the distribution of fur color was again recorded. Which of the following could best explain the change in fur color distribution, as shown in the table below?

The field was primarily composed of light-colored soil and little vegetation, affording gray mice protection from predators.

Which of the following are examples of postzygotic genetic isolating mechanisms?

The progeny of a cross between two different lizard species fail to develop properly.

In eastern gray squirrels, Sciurus carolinensis, the allele for black fur (B) is dominant to the allele for gray fur (b). In a particular population of gray squirrels, 64% have black fur and 36% have gray fur. A researcher calculated the allelic frequencies to be B=0.4 and b=0.6. Five years later, the researcher returned to the location and determined the allelic frequencies within the squirrel population to be B=0.6 and b=0.4. Which of the following could best explain the increase in the frequency of the B allele in the population after five years?

The environment selected against the b allele.

The environment selected for the B allele.

The amino acid sequence of cytochrome c was determined for five different species of vertebrates. The table below shows the number of differences in the sequences between each pair of species. Using the data in the table, which of the following characteristics would a resulting phylogenetic tree showing the relationship between the 5 species have? Check all that apply.

E. ferus and E. africanus would be close together.

E. ferus and D. polylepis would be on branches the furthest apart.

A survey reveals that 25 percent of a population of 1,000 individuals have attached earlobes (are homozygous recessive for the trait). For the following questions, assume that the population fits the parameters of the Hardy-Weinberg law. What is the frequency of the dominant allele?

0.5

A small number of lizards from a mainland population have been deposited on four isolated islands because of the effects of a rare strong storm. Which of the following best describes this?

Founder effect

Scientists are interested in determining the evolution of seven lizard species found on different islands of the Canary Island group. They isolated DNA from individuals of each species and sequenced the mitochondrial gene that encodes cytochrome b. The numbers of genetic differences between species are shown in the table below. Based on the data in the table, which of the following lizard species will be likely furtherest apart on a phylogenetic tree?

Species G and species A

Which of the following has been theorized as being the first to hold genetic material?

RNA

Compare and contrast analogous and homologous structures.

Ultimately what causes variation among organisms?

Mutations

Many species of corals are threatened by the increasing temperatures and decreasing pH of ocean waters. One species, Stylophora pistillata, has been found to thrive in water that is warmer and has a lower pH than the water that corals typically thrive in. Additionally, researchers have found that the tolerance for the new water conditions is heritable. Which of the following statements best explains the changes seen in S. pistillata in response to the changing water conditions?

Directional natural selection

Which of the following descriptions explains the graph below?

Natural stabilizing selection

Which of the following is most responsible for how bacteria share antibiotic resistance with other bacteria?

Plasmids

If p equals the frequency of the dominant allele and q equals the frequency of the recessive allele, which of the following terms represents the frequency of the individuals who show the heterozygous genotype?

2pq

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?

The bacteria have high genetic variability and high reproductive rates.

The condition in which there are barriers to successful interbreeding between individuals of different species in the same community is referred to as

reproductive isolation

Which of the following is a great use for the H/W Equilibrium considering that it is rare to find in nature?

It makes for a great negative control or null-hypothesis.

Undersea landslides can disrupt marine habitats by burying organisms that live on the ocean floor. The graph above shows the size of a population of a certain organism that lives on the ocean floor. The population was affected by a recent landslide at the time indicated on the graph. Which of the following best predicts how the population will be affected by the landslide?

The reduced population will likely have allelic frequencies that are different from the initial population.

Which of the following could explain the variation in shell colors in the below snail population? Check all that apply.

Recessive alleles

Mutations

Evolution occurs when

Hardy-Weinberg Equilibrium is altered.

Are amphibians going extinct?

Yes, if current extinction rates are outpacing speciation rates.

BONUS: Gregor Mendel completed 2 important crosses, the P cross and the F1 cross, resulting in 3 distinct generations. What was the allele frequency over these 3 generations of the F and f alleles?

P Gen (F=0.5 & f=0.5); F1 (F=0.5 & f=0.5); F2 (F=0.5 & f=0.5)

Which of the following observations would provide the strongest evidence that two plants belong to different biological species?

They produce viable but sterile offspring.

The medium ground finch (Geospiza fortis) is a Galapagos island bird species that in 1977 experience a drought so severe that the population fell from approximately 1200 members to 180. PREDICT what happened based upon the data shown below. Check all that apply.

Directional selection

Bottleneck Effect

Living cells typically have biosynthetic pathways to synthesize at least some of the amino acids used in making proteins. Some strains of E. coli, a prokaryote, can synthesize the amino acid tryptophan, while other E. coli strains cannot. Similarly, some strains of the yeast S. cerevisiae, a eukaryote, can synthesize tryptophan, while other S. cerevisiae strains cannot. Which of the following describes the most likely source of genetic variation found in the tryptophan synthesis pathways of both species?

Errors in DNA replication lead to genetic variation.

When was Lamarck right?

Epigenetics

Blackcap birds (Sylvia atricapilla) migrate out of Germany before wintertime. Prior to the 1960s, all members of a particular blackcap population flew to Spain, which had an abundant natural food source. Now, some members of the same blackcap population fly to the United Kingdom, where food placed in feeders by humans is abundant. The blackcaps return to the same forests in Germany to nest during the breeding season. Some blackcaps that migrate to the United Kingdom have become distinguishable by certain physical and behavioral traits from blackcaps that migrate to Spain. Which of the following best predicts the effect on the blackcap population if humans in the United Kingdom continue to place food in feeders during the winter?

The blackcaps that migrate to the United Kingdom will become reproductively isolated from the blackcaps that migrate to Spain, resulting in speciation in the blackcap population.