AP Bio Chapter something

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.

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 next best 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

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.

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 21st 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.

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 19th 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 19th century. By the end of the 20th 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 19th 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 20th led to cleaner air and a lightening of the moth's normal habitat.

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.

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

0.29

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

The distribution of 4 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 not 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.

In eastern gray squirrels, sciurus carolinesis, 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=0.6B and b=0.4b. 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.

In a certain small mammal, fur color is controlled by a pair of alleles, with B being dominant over b. The genotypes BB and Bb result in dark-colored fur, the genotype bb results in light-colored fur. A population of the species has the following allele frequencies: B=0.85 and b=0.15. 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.

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.

A scientist maintains a large population of the fruit fly Drosophilia 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.

There are two species of elephant seals: northern elephant seals, mirounga angustirostris, found off the western coast on 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