College Board Unit 7 Review

Geologic events such as mountain building can directly affect biodiversity. The Sino‑Himalayan fern, Lepisorus clathratus is widely distributed on the Qinghai‑Tibetan plateau. If geologic events lead to a series of new mountain ranges that divide the plateau into several discrete valleys, which of the following best describes how the L. clathratus population would be affected?

Geographic isolation will create separate gene pools, leading to speciation over time.

Scientists want to determine the age of four fossil specimens. They have analyzed the fossils and gathered the data shown in Table 1. *amino acid differences of a conserved protein compared with a fifth fossil specimen Which of the specimens indicated in the table is the oldest?

Specimen 4

Figure 1. Rock color and coat color at three sites on a lava flow (West, Mid, and East), and three nearby sites: O'Neill Hills (O'Neill), the Tule Mountains (Tule), and Christmas Pass (Xmas) In the Arizona populations, the melanocortin-1 receptor (MC1R)(MC1R) gene is responsible for coat color phenotype (light or dark). The MC1RDMC1R⁢D allele, which results in a dark coat, is dominant to the dd allele. Researchers collected samples of mice from all six study sites and sequenced the MC1RMC1R gene. They also collected mice with dark coats from a location in New Mexico, the Carrizozo lava flow, to determine if the MC1RMC1Rgene was also responsible for the dark coat colors observed in that population. The rock pocket mouse population in Carrizozo is isolated from the populations in Arizona. Table 1 presents the genotypic data from sampled mice from all seven locations. The researchers determined that the East lava flow population is not in Hardy-Weinberg equilibrium. Which of the following best explains why the population is not in Hardy-Weinberg equilibrium?

The presence of MC1Rd alleles in the East lava flow population is an indication of gene flow from mice populations living on light granite rocks.

Catalase is a protein enzyme that catalyzes the breakdown of hydrogen peroxide (H2O2) into water and oxygen gas in the cells of many living organisms. Students used an online database, which used the structure of catalase from different species, to generate the phylogenetic tree shown in Figure 1. Which of the following student claims is best supported by the data provided?

Cattle and sheep are separated by only one node, and they are separated from the other organisms by more than one node.

Of the following, which is the best next step for the researchers to best determine the long-term effectiveness of these insecticides with regards to the development of resistance?

Continue treating the three insect populations with the same insecticides and determine whether their efficiencies decline significantly after several generations.

Figure 1. Rock color and coat color at three sites on a lava flow (West, Mid, and East), and three nearby sites: O'Neill Hills (O'Neill), the Tule Mountains (Tule), and Christmas Pass (Xmas) In the Arizona populations, the melanocortin-1 receptor (MC1R)(MC1R) gene is responsible for coat color phenotype (light or dark). The MC1RDMC1R⁢D allele, which results in a dark coat, is dominant to the dd allele. Researchers collected samples of mice from all six study sites and sequenced the MC1RMC1R gene. They also collected mice with dark coats from a location in New Mexico, the Carrizozo lava flow, to determine if the MC1RMC1Rgene was also responsible for the dark coat colors observed in that population. The rock pocket mouse population in Carrizozo is isolated from the populations in Arizona. Table 1 presents the genotypic data from sampled mice from all seven locations. Which of the following is closest to the frequency of the MC1RDMC1RD allele in the Tule Mountain population?

0.03

In addition to the ABO blood groups, humans have an MN blood type system in which the M and N alleles are codominant to one another. A group of scientists found that in one population the frequency of the M allele was 0.82, and the frequency of the N allele was 0.18. Assuming that the population is in Hardy‑Weinberg equilibrium, which of the following is the expected frequency of individuals with the genotype MN?

0.295

Figure 1. Rock color and coat color at three sites on a lava flow (West, Mid, and East), and three nearby sites: O'Neill Hills (O'Neill), the Tule Mountains (Tule), and Christmas Pass (Xmas) In the Arizona populations, the melanocortin-1 receptor (MC1R)(MC1R) gene is responsible for coat color phenotype (light or dark). The MC1RDMC1R⁢D allele, which results in a dark coat, is dominant to the dd allele. Researchers collected samples of mice from all six study sites and sequenced the MC1RMC1R gene. They also collected mice with dark coats from a location in New Mexico, the Carrizozo lava flow, to determine if the MC1RMC1Rgene was also responsible for the dark coat colors observed in that population. The rock pocket mouse population in Carrizozo is isolated from the populations in Arizona. Table 1 presents the genotypic data from sampled mice from all seven locations. Owls (primary predators of rock pocket mice) are nocturnal visual predators that are able to distinguish effectively between dark and light colors in low-light conditions. Which of the following best explains the relationship between coat color and predation rate in the rock pocket mouse population on the lava flow rocks with respect to the different coat color phenotypes?

A dark coat color provides camouflage to mice on the lava flow rocks; therefore, mice with dark coats have a lower predation rate in that habitat.

One facet of the study of the origin of life focuses on the nature of the first genetic material. Figure 1 describes a possible scenario, known as the RNA World Hypothesis, that could have led to the evolution of our modern-day genetic material. This hypothesis states that the first genetic material was RNA, not DNA, and a transitional period led to the emergence of DNA as the storage molecule for genetic material. A scientist wishes to provide experimental evidence to support the model shown in Figure 1 by demonstrating the ability to synthesize an RNA molecule. Which of the following is an alternative hypothesis that can be tested to support the RNA World Hypothesis?

A mixture of ribonucleotides such as adenine and uracil will spontaneously form single-stranded chains of RNA.

Figure 1 shows some major structural changes between a typical prokaryotic cell, the first eukaryotic common ancestor, and the last eukaryotic common ancestor. Based on the information provided in the figure, which of the following best describes how membrane-bound organelles provided unique evolutionary advantages to the last eukaryotic common ancestor?

Cells with mitochondria were able to utilize metabolic energy more efficiently.

Whales, bony fishes, and cartilaginous fishes all have similar adaptations that enable them to live in the ocean. Figure 1 shows the phylogenetic relationships of selected vertebrates. Based on the phylogenetic relationships shown in Figure 1, which of the following best explains the similarities exhibited by whales, bony fishes, and cartilaginous fishes?

Convergent evolution, because these organisms do not share a recent common ancestor.

Figure 1. Rock color and coat color at three sites on a lava flow (West, Mid, and East), and three nearby sites: O'Neill Hills (O'Neill), the Tule Mountains (Tule), and Christmas Pass (Xmas) In the Arizona populations, the melanocortin-1 receptor (MC1R)(MC1R) gene is responsible for coat color phenotype (light or dark). The MC1RDMC1R⁢D allele, which results in a dark coat, is dominant to the dd allele. Researchers collected samples of mice from all six study sites and sequenced the MC1RMC1R gene. They also collected mice with dark coats from a location in New Mexico, the Carrizozo lava flow, to determine if the MC1RMC1Rgene was also responsible for the dark coat colors observed in that population. The rock pocket mouse population in Carrizozo is isolated from the populations in Arizona. Table 1 presents the genotypic data from sampled mice from all seven locations. Which of the following best describes the processes occurring between the mouse populations and their environments?

Dark color is selected for in mice from the West, Mid, and East populations.

A 100 acre woodlot was observed for the last forty years. Five plant species (1 through 5) were surveyed, with the results shown in Table 1. Some researchers claim that the decrease in plant species richness of this woodlot is unrelated to human activities over the last forty years. Which of the following would be an appropriate alternative hypothesis?

During the last few decades, tall buildings have been built around the woodlot, and species 3, 4, and 5 are shade‑intolerant plants

Tobacco hawk moths, Manduca sexta, feed exclusively on sugar-rich nectar produced in the flowers of tobacco plants. To feed, the moth inserts its proboscis (a long, tubular mouthpart) into the flower to reach the nectary, which is usually at the end of a long tube in the flower. Moths will feed on the nectar of the tobacco plant species whose nectaries they can access. A study determined the proboscis sizes in one tobacco hawk moth population. The data are shown in Figure 1. The most abundant tobacco species in the population's habitat has a nectary tube that is 5cm long. Over the next year, a virus attacks and rapidly kills almost all plants of the tobacco species. A closely related species of tobacco that is resistant to the virus becomes established during that same year. The nectary tube in the resistant species averages 7.5cm. Scientists monitored the area for the next five years to determine how this change affected the moth population. Which of the following best describes the expected distribution of proboscis size of the moths at the end of the five‑year study?

Graph B

Mollusk fossils were excavated and collected from a coastal cliff. Scientists studying the fossils observed patterns of changing shell shape in the mollusks. The scientists identified a period of stability or stasis, followed by rapid change, and then stasis again with regard to shell shape. Which of the following statements best predicts the result of a comparison between the fossils found before and after the period of rapid change?

Most of the species found in the first static period will be absent in the second static period.

Students created a model showing one possible mechanism for speciation in which a geographic barrier separated one large population into two smaller populations, A and B. Over time, populations A and B developed into two distinct species. The model is shown in Figure 1 Which of the following best describes what occurred during the periods indicated by the arrows?

Natural selection acted on variation that was present in both populations A and B, and the lack of gene flow eventually led to the formation of two new species.

Because cheetahs, Acinonyx jubatus, experienced a bottleneck event about ten thousand years ago, living cheetahs exhibit very little genetic variation compared to other living species of large cats. Which of the following principles best justifies a claim that cheetahs, compared to other large cats, have a relatively low resilience to environmental perturbations?

Populations with little genetic diversity are less likely to contain individuals that can withstand different selective pressures.

In a particular region, a species of lizard lives in the lowlands. Even though there are numerous mountains in the region, the climate on the mountains is too cold for the lizards to survive. Scientists are concerned that the lowlands will become much warmer by the end of the twenty-first century and will become unsuitable for this lowland lizard species. Which of the following best predicts the impact on the lizard species if there is a gradual increase in the average temperatures found in both the lowlands and mountains in this region?

Some lizards will migrate to new habitats in the mountains and become isolated, leading to allopatric speciation.

The degrees of relatedness in several native populations of prairie chickens in Marion and Jasper Counties in Illinois were determined. The degree of relatedness is inversely proportional to genetic diversity; that is, populations with a high degree of relatedness have less genetic diversity. Table 1 shows the collected data. Populations J1J1 through J5J5 are located in Jasper County. Populations M1M1 through M5M5 are located in Marion County. Numbers above 0.125 indicate a high degree of relatedness. Scientists claim that some of the populations in Marion County are at an increased risk of decline or extinction. Based on the data in table 1, which of the following best provides evidence to support this claim?

The M4 and M5 populations have the lowest genetic diversity of all populations.

Researchers have undertaken a long-term study of populations of rock pocket mice, Chaetodipus intermedius, in Arizona and New Mexico. Rock pocket mouse fur is either dark or light in color. Most of the populations studied live in areas with light-colored granite rocks; however, some areas are dominated by dark-colored rocks from ancient lava flows. Researchers collected mice from six sites in Arizona and recorded their coat colors. Figure 1 shows the study sites, the rock colors, and the distribution of coat colors. Figure 1. Rock color and coat color at three sites on a lava flow (West, Mid, and East), and three nearby sites: O'Neill Hills (O'Neill), the Tule Mountains (Tule), and Christmas Pass (Xmas) In the Arizona populations, the melanocortin-1 receptor (MC1R)(MC1R) gene is responsible for coat color phenotype (light or dark). The MC1RDMC1R⁢D allele, which results in a dark coat, is dominant to the dd allele. Researchers collected samples of mice from all six study sites and sequenced the MC1RMC1R gene. They also collected mice with dark coats from a location in New Mexico, the Carrizozo lava flow, to determine if the MC1RMC1Rgene was also responsible for the dark coat colors observed in that population. The rock pocket mouse population in Carrizozo is isolated from the populations in Arizona. Table 1 presents the genotypic data from sampled mice from all seven locations. Based on the data in Table 1, which of the following best describes the relationship between the MC1RMC1R gene and coat color in the Carrizozo, New Mexico, rock pocket mouse population?

The MC1RDMC1RD allele is not responsible for dark coat color in the Carrizozo population, so the dark coat color is likely a result of convergent evolution.

The distribution of four populations of giant kangaroo rats, Dipodomys ingens, living on the same island when it was first surveyed in 1789 are shown in Figure 1. In 1852, there was a large earthquake which altered the island's geography, as shown in Figure 2. The island was surveyed again in 2015, and scientists determined that the giant kangaroo rats originally in population A are now to be considered as a new species. Which of the following best explains the mechanism that caused this speciation event in the giant kangaroo rats of population A?

The animals in population A were reproductively isolated from those in populations B, C, and D. The animals in population A were reproductively isolated from those in populations B, C, and D. B

Figure 1. Rock color and coat color at three sites on a lava flow (West, Mid, and East), and three nearby sites: O'Neill Hills (O'Neill), the Tule Mountains (Tule), and Christmas Pass (Xmas) In the Arizona populations, the melanocortin-1 receptor (MC1R)(MC1R) gene is responsible for coat color phenotype (light or dark). The MC1RDMC1R⁢D allele, which results in a dark coat, is dominant to the dd allele. Researchers collected samples of mice from all six study sites and sequenced the MC1RMC1R gene. They also collected mice with dark coats from a location in New Mexico, the Carrizozo lava flow, to determine if the MC1RMC1Rgene was also responsible for the dark coat colors observed in that population. The rock pocket mouse population in Carrizozo is isolated from the populations in Arizona. Table 1 presents the genotypic data from sampled mice from all seven locations. The researchers built an enclosure to prevent migration into and out of the O'Neill rock pocket mouse population for a period of two years. Which of the following best predicts the effect of the enclosure on the O'Neill population?

The frequency of the MC1RD allele will decline due to natural selection.

A famous study from the nineteenth century involves the peppered moth, Biston betularia, commonly found in Great Britain and Ireland. At that time, the moths, normally white with black speckles, known as the peppered variety, became less common than the solid black variety. The population was predominantly black throughout the nineteenth century. By the end of the twentieth century, the peppered version of the moth was again more common than the black version. Which of the following best explains the phenotypic pattern in the moths over time?

The increased air pollution of the nineteenth century due to the use of coal led to a darkening of surfaces from soot. The darker backgrounds conferred a selective advantage to the black variety, as described by natural selection. A shift to less polluting fuel in the twentieth led to cleaner air and a lightening of the moth's normal habitat.

Some plant species flower in response to increasing daily temperatures in the spring. Many of these species rely on pollinators that migrate based on changes in day length and the position of the Sun. The current global warming trend is placing new selective pressures on the species involved in these relationships. Which of the following best explains the impact of these new selective pressures on the organisms involved?

The plant species will flower earlier in the spring in response to rising temperatures before the arrival of the pollinators, so seeds will not be produced.