AP Bio Unit 7 Quiz

Humans vary in their ability to taste the bitter chemical compound phenylthiocarbamide (PTCPTC). The taster phenotype is dominant to the nontaster phenotype. Researchers tested the PTCPTC taster phenotype of individuals from an isolated population. In the sample, 780 individuals were able to taste PTCPTC and 70 individuals were not able to taste PTCPTC. Assuming the population is in Hardy-Weinberg equilibrium, what is the frequency of the non-taster allele?

0.29

In a long‑term study of a population of gray squirrels, researchers observed that most of the squirrels had gray fur. However, there were some individuals in the population with white fur (albino). Genetic analysis revealed that the albino condition is expressed by individuals who are homozygous recessive (gg)(��). Over a ten-year period, the average frequency of albino squirrels in the population was 0.18. If the population is assumed to be in Hardy-Weinberg equilibrium, the average frequency of the dominant allele is closest to which of the following?

0.58

Gaucher disease type 1 (GD1GD1) is a recessive genetic disease that affects 1 in 900 individuals in a particular population. GD1GD1 is caused by a mutation in the enzyme glucocerebrosidase. Assuming the population is in Hardy-Weinberg equilibrium, calculate the frequency of the wild-type (nonmutant) allele for the enzyme glucocerebrosidase.

0.967

In a large, isolated population of an insect species, a specific gene locus has one dominant allele (A)(�) and one recessive allele (a)(�). The genotype frequencies of the gene were collected for ten generations, as shown in Table 1. Which of the following could best account for the change in genotypic frequencies over the ten generations?

Because the A� allele is unstable, over the course of the study most of the A� alleles mutated to become a� alleles.

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?

Cell wall composed of cellulose

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 DNADNA 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?

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

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.

Human hunting of elephants with tusks between 1977 and 1992.

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?

Location of fossils and shell orientation

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?

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

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?

Organism I

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.

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

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 ?

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

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?

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

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.

Two species of fish that live in extremely cold environments produce near-identical antifreeze glycoproteins, called AFGPsAFGPs. Scientists have determined the origins of the AFGPAFGP 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 AFGPsAFGPs in these two species of fish?

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

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�=0.4 and b=0.6�=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�=0.6 and b=0.4�=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 frequency of the B� allele increased due to the selective pressures of the environment.

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?

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.

In humans, one allele of the APOE gene, called APOE-ε22, 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-ε22 allele. Which of the following states a valid null hypothesis about the future distribution of APOE alleles in future generations in the United States?

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.

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 ?

They reflect the number of base pair changes in the DNA

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

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

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?

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

Which of the following statements best explains how a condition of Hardy-Weinberg equilibrium results in a population that exhibits stable allele frequencies (i.e., a nonevolving population) ?

Without migration or mutation, new alleles cannot be introduced to the population.

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.

artificial selection