Unit 7 AP Bio

A Wilson biologist student is studying a population of the Mojave desert pocket mouse with two different color phenotypes among the irregular lava flow outcrop of the Mojave desert. The color phenotype is controlled by a single gene with two alleles: an complete dominant allele A Unknown node type: brUnknown node type: br(dark fur) and a recessive allele a (light fur). The student collected data on the color of 100 pocket mice. The student calculated that the recessive allelic frequency is 0.5. What is the dominant phenotypic frequency for this particular population of pocket mice?

.75

Humans vary in their ability to taste the bitter chemical compound phenylthiocarbamide (PCT). The taster phenotype is dominant to the nontaster phenotype. Researchers tested the PCT taster phenotype of individuals from an isolated population. In the sample, 870 individuals were able to taste PCT and 90 individuals were not able to taste PCT. Assuming the population is in Hardy-Weinberg equilibrium, what is the frequency of the non-taster allele?

0.31

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 . What is the allelic frequencies of black fur? P2 + 2Pq + q2 = 1 P + q = 1

0.4

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 was the frequency of allele G in the gray moths that emerged in 1980?

0.50

Cystic fibrosis is a recessive condition that affects about 1 in 2,500 babies in the Caucasian population of the United States. Assuming the population is in Hardy-Weinberg equilibrium, calculate the frequency of the wild-type (nonmutant) allele for cystic fibrosis.

0.98

One of the oldest known mammalian fossils belongs to a small furry species, Hadrocodium wui, that lived 195 million years ago. For the following 100 million years, only a small number of groups of mammalian fossils are found in the fossil record. By 65 million years ago, the nonavian dinosaurs were extinct. By 55 million years ago, there were 130 mammal genera, including 4,000 different species that occupied a wide variety of habitats. Which of the following best describes the cause of the rapid increase in the number of mammalian species between 65 and 55 million years ago?

After the dinosaur extinction, many ecological niches became available, leading to the adaptive radiation of mammals.

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.

Paleoclimatic analysis has generated a claim that there is a possible correlation between an extinction event around 29 million years ago that allowed grasslands to become abundant and the adaptive radiation of several groups of butterflies. Which of the following proposes the best alternative hypothesis for the claim?

Climate analysis conducted by sampling pollen preserved in amber shows an increase in grass pollen 29 million years ago, which indicates there was an increase in grasslands that correlates to an increase in butterfly speciation during the same time period.

Researchers were modeling the effects of repeated cycles of isolation with occasional interbreeding among five hypothetical fish species (species A, B, C, D, and E) found in two separate lakes (lakes I and II) that are occasionally joined by flooding, as shown in Figure 1. The research team indicated that species A would be considered to be the single common ancestor of species B, C, D, and E. (figure 1)

DNA analysis shows fewer differences between species A and species B in Lake I than between species B and the populations in Lake II.

A species of snail lives in the intertidal zone along the coast of New England. The dark-colored variety of the species is more common in northern New England, the light-colored variety is more common two hundred miles away in southern New England, and both varieties are commonly found together in central New England. Which of the following best explains the observed distribution pattern of the snails?

Dark-colored snails absorb more solar energy and so survive more readily in the colder northern waters.

Staphylococcus aureus is a pathogenic bacterium that can infect a wide range of host species, including humans. S. aureus has a particular protein that binds with hemoglobin from the host organism. Hemoglobin is the iron-containing protein used to transport oxygen in the blood. Since iron is important for growth, S. aureus have evolved the ability to absorb the iron from the host's hemoglobin. Different S. aureus strains preferentially infect different hosts and have different amino acid sequences at their hemoglobin-binding domains (Table 1; letters indicate different amino acids). Table 1. Selected amino acid sequences and preferred host for four strains of S. aureus. Which of the following processes is most consistent with the differences in the amino acid sequences listed in Table 1?

Each strain is best adapted to a specific host species.

Using the evidence provided, which of the following best justifies the researchers' claim?

Finch beak depth increased as a consequence of selective pressure after the drought because the remaining seeds were larger and harder.

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. Which of the following best describes the process responsible for the change in the percent of tuskless female elephants in the Gorongosa National Park population shown in Figure 1 ?

Human hunting of elephants with tusks between 1977 and 1992.

Which of the following best explains how the ecological conditions are likely to be different in the two models?

In model A the ecological conditions change gradually over a long period of time; in model B the ecological conditions remain unchanged for long periods of time and then change drastically.

Rock pocket mice live in the deserts of the American southwest. Ancestral pocket mice all had light-colored coats that blended in with the region's rocks and sandy soil, keeping the mice hidden from predatory owls. About 1.7 million years ago, a series of volcanic eruptions spewed out wide trails of black lava into the middle of rock pocket mouse territory. Currently there are two color morphs of rock pocket mice: light-colored mice that are typically found in habitats with sandy soil, and dark-colored mice that are typically found in habitats with dark-colored lava rocks. Which of the following best justifies the claim that alleles that may be adaptive in one type of environment can be deleterious in another because of different selective pressures?

Light-colored mice are significantly more susceptible to predation by owls in habitats with lava rocks than in habitats with sandy soil.

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.

Which of the following factors is the most effective in changing the allele frequency in a natural population?

Natural selection

In a large, isolated population of an insect species, a specific gene locus has one dominant allele (A)Unknown node type: brUnknown node type: brand one recessive allele (a)Unknown node type: brUnknown node type: br. 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?

Nonrandom mating that preferentially led to mating between AA and aa individuals could result in the observed increase in Aa genotype frequencies.

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. Based on the data in Figure 1, which of the following best describes the concept illustrated?

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

A scientist is attempting to provide support for the hypothesis that RNA was the first genetic material. Which of the following would be a workable alternate hypothesis?

RNA can be observed to self-replicate without the assistance of proteins, while DNA always requires protein-based enzymes to replicate.

In a population of coyotes, there is variation in the size of individual animals. Larger animals are able to bring down larger prey but also require more food to survive. In a particular area, the primary food source for many years had been rabbits, but disease led to a sudden crash in the rabbit population. However, the deer population in the area increased at about the same time. Over time, naturalists noted that the average size of coyotes in the population had increased. Which of the following is the best explanation for the increase in average coyote size following the crash in the rabbit population?

Smaller coyotes were at a hunting disadvantage, so fewer survived long enough to reproduce.

able 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. Table 1. Average milk production per cow (in kilograms per cow per year) 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.

Researchers were modeling the effects of repeated cycles of isolation with occasional interbreeding among five hypothetical fish species (species A, B, C, D, and E) found in two separate lakes (lakes I and II) that are occasionally joined by flooding, as shown in Figure 1. The research team indicated that species A would be considered to be the single common ancestor of species B, C, D, and E.

Sympatric speciation

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.

In a hypothetical population of beetles, there is a wide variety of color, matching the range of coloration of the tree trunks on which the beetles hide from predators. The graphs below illustrate four possible changes to the beetle population as a result of a change in the environment due to pollution that darkened the tree trunks.

The coloration in the population shifted toward more darker-colored beetles, as in diagram IV. The lighter colored beetles were found more easily by the predators than were the darker-colored beetles.The coloration in the population shifted toward more darker-colored beetles, as in diagram IV. The lighter colored beetles were found more easily by the predators than were the darker-colored beetles.

Commercial bananas are grown as a monoculture, with all banana plants cloned from one original banana plant. The commercial strains of bananas are seedless, so each new banana plant has to be manually planted from a cutting of an existing banana root. In the 1950s, the Gros Michel banana strain, the dominant export banana at that time, was destroyed by the fungus Fusarium oxysporum. A new Fusarium resistant variety, the Cavendish banana, was developed and is currently the banana strain grown for export. Recently, a Fusarium strain that successfully attacks the Cavendish strain has been documented. Which of the following best provides reasoning supporting a method that would help protect commercial banana crops from infection by pathogenic organisms such as Fusarium fungi?

The commercial banana strains should not be grown in monocultures, since many pathogenic organisms are able to evolve rapidly in response to a single selective pressure.

Some scientists claim that amphibians are currently experiencing a period of mass extinction. Which of the following should be included in an alternative hypothesis that would best support this claim? Responses

The current extinction rate of amphibians compared with the background rate of extinction as determined by the fossil record

Female European corn borer moths (Ostrinia nubilalis) produce the sex pheromone 11−tetradecenyl acetate (11−TDA), which attracts males of their species. 11−TDA can be produced in two forms, E and Z, each with a different three-dimensional shape. Researchers have discovered two different strains of the European corn borer moth living in the same area. Females of the E strain produce primarily the E form of 11−TDA and females of the Z strain produce primarily the Z form of 11−TDA. Males of both strains are more attracted to the form of 11−TDA produced by the females of the same strain. Which of the following best predicts a long-term effect of the differences between the E and Z strains? Responses

The difference between the forms of the sex pheromone 11−TDA produced by E and Z strains will act as a prezygotic reproductive barrier leading to sympatric speciation.

A group of mice was released into a large field to which no other mice had access. Immediately after the release, a representative sample of the mice was captured, and the fur color of each individual in the sample was observed and recorded. The mice were then returned to the field. After twenty years, another representative sample of the mice was captured, and the fur color of each individual in the sample was again recorded. Which of the following best explains the change in the frequency distribution of fur color phenotypes in the mouse population, as shown in the figures above?

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

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.

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

Two species of fish that live in extremely cold environments produce near-identical antifreeze glycoproteins, called AFGPs. Scientists have determined the origins of the AFGP gene in both species. Selected characteristics of the two fish species are provided in Table 1. Table 1. Characteristics of two fish species producing nearly identical antifreeze glycoproteins. Two species of fish that live in extremely cold environments produce near-identical antifreeze glycoproteins, called AFGPs. Scientists have determined the origins of the AFGP gene in both species. Selected characteristics of the two fish species are provided in Table 1. Table 1. Characteristics of two fish species producing nearly identical antifreeze glycoproteins

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 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 Unknown node type: brUnknown node type: brallele in the population after five years?

The frequency of the B allele increased due to the selective pressures of the environment.

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 predicts the outcome of these lizards reproducing for many generations on the islands?

The isolation prevents gene flow; thus, the lizards on different islands experience prezygotic isolation.

Many scientists claim that the synthesis of the first organic molecules from inorganic precursors was possible because of the highly reducing atmosphere found on primitive Earth. Which of the following is an appropriate null hypothesis that could be used when investigating the claim?

The level of atmospheric oxygen on modern Earth is significantly higher than on primitive Earth.

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. Table 1. Observed number of salamanders by phenotype before and after a spring flood Salamander Distribution before the Flood (n)Salamander Distribution after the Flood (n)Black phenotype137Dark-brown phenotype2514Light-brown phenotype63 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.

Dr. Robert Hazen has worked to develop a hypothesis that explains the origin of life on Earth. His work has focused on hydrothermal vents, which are cracks in the ocean floor. Water heated by molten rock beneath the crust escapes from these vents at very high temperatures, producing hot, high‑pressure environments at the vents on the ocean floor. In order to provide evidence that these vents may be areas where life originated, which of the following states a null hypothesis Hazen might have used to begin his research?

The temperatures and pressures found in hydrothermal vents resemble conditions described in currently accepted origins of life hypotheses.

Scientists want to determine whether the rapid economic growth in China between 1950 and 2000 caused a mass extinction of animal species during that time period. A mass extinction event is considered to occur when the rate of species extinction far exceeds the background extinction rate. The scientists collected data on the number of extinctions of selected vertebrate species in China between 1950 and 2000, as shown in Table 1. Extinction rates were ascertained by measuring the average percent of species lost (PSL). Which of the following is the null hypothesis most relevant for evaluating the data in Table 1 ?

There is no significant difference between the extinction rate of animals between 1950 and 2000 in China and the background extinction rate.

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 RNA 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