ap bio unit 7 test

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.

Five new species of bacteria were discovered in Antarctic ice core samples. The nucleotide (base) sequences of rRNA subunits were determined for the new species. The table below shows the number of nucleotide differences between the species. Which of the following phylogenetic trees is most consistent with the data?

3 4 2 1 5

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 percentage of moths in the natural population was white in 1962 ?

4%

In a certain flock of sheep, 4 percent of the population has black wool and 96 percent has white wool. Assume that the population is in Hardy-Weinberg equilibrium. What percentage of the population is homozygous for white wool?

64%

A widely accepted hypothesis about the origin of life on Earth is that life arose approximately 3.5 billion years ago as the result of a complex sequence of chemical reactions that took place spontaneously in Earth's atmosphere. Another hypothesis about the origin of life suggests that life began somewhere else in the universe and arrived on Earth by chance. Which of the following questions might scientists ask to most reliably determine if there has ever been life on Mars?

Did Mars have the elements present in its atmosphere to support life?

The cladogram shows shared traits among four plant taxa. Based on the cladogram, which of the following are the traits shared between ferns and pines?

Embryo and xylem only

A biologist spent many years researching the rate of evolutionary change in the finch populations of a group of islands. It was determined that the average beak size (both length and mass) of finches in a certain population increased dramatically during an intense drought between 1981 and 1987. During the drought, there was a reduction in the number of plants producing thin-walled seeds. Which of the following statements might best explain the increase in average beak size in the finch population during the drought?

Finches with bigger beaks are better able to crack thick-walled seeds and produce more surviving offspring.

Low doses of antibiotics are often added to livestock feed to increase production. Studies have shown that bacterial populations constantly exposed to the sublethal doses can evolve resistance to the antibiotics. A research group claimed that when a population of bacteria are constantly exposed to sublethal doses of streptomycin, their fitness declines due to the increased energy requirements for survival in the presence of the antibiotic. For subsequent studies, the researchers wish to determine whether adding a low, sublethal dose of an additional antibiotic causes further decline in the fitness of the bacteria. Which of the following best represents the next step the researchers should take with respect to experimental design?

Group 1: low dose of streptomycin + no dose of additional antibiotic Group 2: low dose of streptomycin +low dose of additional antibiotic

Scientists are studying several populations of finches on neighboring islands in the South Pacific. Previous genetic analysis has shown that a single gene controls tail-feather length in the finch populations and that the allele for long tail feathers (L) is dominant to the allele for short tail feathers (l) . On two separate islands, the scientists recorded the number of finches with long tail feathers and the number of finches with short tail feathers. The results are shown in the table below. If the two finch populations are each in Hardy-Weinberg equilibrium and are isolated from each other, then which of the following graphs correctly displays the relative genotype frequencies?

LL = island 1: 0.1 island 2: 0.2 Ll= island 1: 0.6 island 2: 0.1 ll= island 1: 0.2 island 2: 0.35

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.

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

Selection

Many species of corals are threatened by the increasing temperatures and decreasing pH of ocean waters. One species, Stylophora pistillata, has been found to thrive in water that is warmer and has a lower pH than the water that corals typically thrive in. Additionally, researchers have found that the tolerance for the new water conditions is heritable. Which of the following statements best explains the changes seen in S. pistillata in response to the changing water conditions?

The corals' adaptation is an example of natural selection because the tolerance is in response to a changing environment and has a genetic basis.

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. Which of the following could best explain the change in fur color distribution, as shown in the table above?

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

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.

Figure 1. Experimental steps taken to determine whether the nutrient source in a growth chamber affects mating preference A population of fruit flies (Drosophila pseudoobscura) grown on a typical nutrient source was separated into several growth chambers. Each of the new chambers was assigned a different source of carbohydrates for nutrition, either starch or maltose, and maintained for many generations (Figure 1). After a year, male and female flies were paired up in different combinations. The instances of mating between the males and females grown on the same nutrient source and males and females grown on different nutrient sources were recorded (Table 1). To test whether the mating preferences were simply the result of being isolated in separate growth chambers, the researchers tested the mating preferences of flies that were both grown on starch, but in either the same or different chambers (Table 2). Which of the following best represents the null hypothesis for the experiment detailed in Figure 1 ?

The mating preferences of flies are not dependent on the nutrient source on which they are grown.

All of the following are examples of prezygotic genetic isolating mechanisms EXCEPT:

The progeny of a cross between two different lizard species fail to develop properly.

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.

Sugar gliders and Northern flying squirrels are mammals that have many morphological similarities despite being genetically different. Both are nocturnal and have large eyes to help them see in the dark. Both live in trees and have flaps of skin connecting their front and back legs, and when their front and back legs are extended, the flaps allow the animals to glide from one tree branch to another. Sugar gliders are native to Australia, and Northern flying squirrels are native to North America. Which of the following best explains the morphological similarities between these two species?

The similarities between the species evolved independently as a result of similar selective pressures in each species' environment.

The apple maggot fly, Rhagoletis pomonella, is native to North America and originally fed on fruit of the wild hawthorn. Since the mid-1800s, a population of flies has emerged that instead feed on domesticated apples. Apple maggot flies typically mate on or near the fruit of their host plants. Many varieties of apples ripen three to four weeks before the hawthorn fruits do. The different fruit preferences of the two fly populations will most likely have which of the following effects?

The single fly species will evolve into two distinct species because of the lack of gene flow between the two populations.

Which of the following pieces of evidence best supports the hypothesis that birds and crocodilians (crocodiles and alligators) are more closely related to each other than they are to other organisms?

The skulls of birds and crocodilians have an opening that is absent in the skulls of other reptiles.

Two populations of a species of squirrel are geographically isolated from each other. Although they have the same population density, one population is significantly larger in number than the other. A new bacterial disease, which is easily spread and extremely virulent, affects both populations at the same time. Which of the following is the best prediction of how the new disease will affect the two populations?

The smaller population will be more affected than will the larger population, because the smaller population has less genetic variation than the larger population has.

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. The phenotypic variation in behavior between the two populations can best be described as resulting from

artificial selection

The table above shows derived characters for selected organisms. Based on the information in the table, which of the following cladograms best represents the evolutionary relationships among the organisms?

cladogram: organisms go across 1. fish 2. amphibians 3. crocodiles 4.birds 5. mammals

Competition for food would probably be most severe between two

closely related species in similar niches

In plants, members of the euphorbia family and the cactus family have separate origins, with the euphorbia evolving in the desert regions of Asia and Africa and the cacti in the desert regions of the Americas. Both have fleshy stems adapted for water storage, protective spines, and leaves that are greatly reduced or absent. The similarities between these two families of plants represent an example of

convergent evolution

The wing of a bat, the flipper of a whale, and the forelimb of a horse appear very different, yet detailed studies reveal the presence of the same basic bone pattern. These structures are examples of

homologous structures

In Darwinian terms, the fittest individuals of a species are those that

leave the greatest number of reproducing descendants

For following group of questions first study the description of the situation and then choose the one best answer to each question following it and fill in the corresponding oval on the answer sheet. A survey reveals that 25 percent of a population of 1,000 individuals have attached earlobes (are homozygous recessivefor the trait). For the following questions, assume that the population fits the parameters of the Hardy-Weinberg law. If p equals the frequency of the dominant allele and q equals the frequency of the recessive allele, which of the following terms represents the frequency of the individuals who show the dominant phenotype?

p2 + 2pq

The fossil record indicates that in some cases reasonably well-defined species appear suddenly and remain unchanged for a long time before they become extinct. This phenomenon is referred to as

punctuated equilibrium