AP Bio: Unit 7 Natural Selection A

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.

Figure 1. Best-fit curve for winning times in the Kentucky Derby since 1880 Which of the following best explains the trend shown in Figure 1?

By 1940, most genetic variation for speed had been lost from the gene pool.

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). Table 1. Characteristics present in four photosynthetic species Green Alga Moss Spruce Tree Apple TreeCell wall composed of cellulose + + + +Vascular tissue − − + +Roots − − + +Seeds enclosed in fruit − − − +Flagellated sperm cells − + − − 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

Henslow's sparrow is a songbird found in North American grasslands. The logging industry created vast meadow habitats for the sparrow in the late 1800s. Henslow's sparrow populations came to a peak in the mid‑1900s. A recent survey of ten Midwest counties are shown in Figure 1. Table 1. Year of Last Documented Observations of Henslow's Sparrow in Ten Selected Midwest Counties CountyNumber of Confirmed ObservationsLast Documented Observation1820072120073220074220155620156320068120049420071042007 Human activities can drive changes in ecosystems that affect the risk of extinction. An experiment is designed to help prevent the further decline and extinction of the Henslow's sparrow in which controlled burns will be set in the each of the ten Midwest counties in order to prevent the regrowth of the forest. Which of the following represents an alternate hypothesis tested by this experiment with regard to the population sizes of Henslow's sparrows?

Controlled fires in counties 4 and 5 will lead to an increase in the sparrow population.

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. Table 1. Data from Forty-Year Survey of Five Plant Species in a Woodlot Year of SurveySpecies 1 PopulationSpecies 2 PopulationSpecies 3 PopulationSpecies 4 PopulationSpecies 5 Population135302332252035422021405050200 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

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.

Figure 1. The frequency of M and N alleles in selected populations Based on the data in Figure 1, which of the following would most affect the allelic frequencies of the populations on Isabela and Butuan

Immigration of individuals from Metro Manila into the two populations

A group of researchers noticed that using a particular drug to treat cancer in mice would reduce the size of the tumor, but some of the tumor cells appeared to be resistant to the drug since some of these cells would increase in number over time. The researchers wish to increase the reliability of their experimental observations before investigating new claims that chemotherapy-resistant tumors are an example of continuing evolution. Of the following, which is the best next step the researchers might take to increase the reliability of their evidence?

Increasing the number of trials and the number of mice in each treatment group

Figure 1. Creating recombinant bacteria that contain a specific gene Which of the following best predicts why the recombinant bacteria will fail to produce the eukaryotic protein?

Introns must be removed from eukaryotic DNA before the gene is inserted into the plasmid.

There are two species of elephant seals: northern elephant seals, Mirounga angustirostris, found off the western coast of North America from Baja California to the Gulf of Alaska, and southern elephant seals, M. leonina, found in the southern oceans. Hunting in the nineteenth century has been blamed for a drastic reduction in the northern elephant seal population. Even though the population has rebounded following restrictions on seal hunting, genetic variation is greatly reduced in the northern species compared to that in the southern species. Which of the following conditions of Hardy-Weinberg equilibrium was most likely not met in the northern elephant seal population following overhunting?

Large population size

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.

Figure 1. Model of speciation 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.

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.

Based on the data in Table 1, which of the following best describes the relationship between the MC1R gene and coat color in the Carrizozo, New Mexico, rock pocket mouse population?

The MC1RD allele is not responsible for dark coat color in the Carrizozo population, so the dark coat color is likely a result of convergent evolution.

Figure 2. Map of the island following the 1852 earthquake 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.

If a fire caused the surface of the ground in the habitat of the species to become darker in color, which of the following claims about the impact on the allele frequencies in this population is most reasonable?

The frequency of the B allele will increase because light-colored individuals will be more visible to predators.

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 scientist is studying the impact of mutagens on genetic variation in mice. In an experiment, the scientist creates two groups of twenty highly inbred mice. Because the mice are highly inbred, they are essentially identical to one another. One group is given food with an added substance that is known to be a mutagen. The second group is fed the same food without the mutagen. After several generations, both groups of mice are given a new type of food that is harder to digest than the previous food. After rearing five additional generations of the mice on this new food, the two groups are assessed for how efficiently this new food is digested. Which of the following is the most reasonable prediction about the results of the experiment?

The group of mice fed the mutagen will show a greater ability to digest the food, because the higher genetic variation within the group makes it more likely that some individuals will have a combination of genes better adapted to the new food.

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.

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.

A scientist maintains a large population of the fruit fly Drosophila affinis in the laboratory. After 20 generations of allowing this population of about 1000 flies to mate randomly, 10 females and 10 males were isolated from the rest of the population. Both the larger population and the isolated population were maintained under identical conditions and allowed to mate randomly for another 20 generations. After the 20 generations, DNA sequencing was used to determine the genetic composition of each population. Which of the following predicts the expected outcome of the experiment?

The two populations will show significant genetic differences because the founder effect will result in significant losses in diversity in the smaller population.

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.