Unit 1 Evolution Test

Human newborns usually weigh between 6-8 pounds. A small minority of babies are smaller and larger than this. This is an example of:

stabilizing selection

Initially, which of the following isolating mechanisms is likely to have been the most important in preventing gene flow between the two populations of Rhagoletis?

temporal isolation

Rhagoletis pomonella is a parasitic fly native to North America that infests fruit trees. The female fly lays her eggs in the fruit. The larvae hatch and burrow through the developing fruit. The next year, the adult flies emerge.Prior to the European colonization of North America, the major host of Rhagoletis was a native species of hawthorn, Crataegus marshallii. The domestic apple tree, Malus domestica, is not native to North America, but was imported by European settlers in the late 1700s and early 1800s.When apple trees were first imported into North America, there was no evidence that Rhagoletis could use them as hosts. Apples set fruit earlier in the season and develop faster, where hawthorns set later and develop more slowly.Recent analysis of Rhagoletis populations has shown that two distinct populations of flies have evolved from the original ancestral population of flies that were parasitic on hawthorns. One population infests only apple trees, and the other infests only hawthorns. The life cycles of both fly populations are coordinated with those of their host trees. The flies of each population apparently can distinguish and select mates with similar host preferences and reject mates from the population specific to the other host tree. There is very little hybridization (only about 5 percent) between the two groups.

the apple tree was imported into North America with European settlement approximately 200 years ago

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

In a population, the dominant phenotype(BE CAREFUL! NOT PHENOTYPE) of a certain trait occurs 64% of the time. What is the frequency of the recessive allele?

0.64

In certain Native American groups, albinism due to a homozygous recessive condition in the biochemical pathway for melanin is sometimes seen. If the frequency of the allele for this condition is 0.06, which of the following is closest to the frequency of the dominant allele in this population? (Assume the population is in Hardy-Weinberg equilibrium)

0.94

In a population that is in Hardy-Weinberg equilibrium, the frequency of a particular recessive allele (a) is 0.4. What is the percentage of the population that is heterozygous (Aa) for this trait?

48%

Data regarding the presence (+) or absence (-) of five derived traits in several different species are shown in the table below. Which of the following cladograms provides the simplest and most accurate representation of the data in the table?

A

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.

The appearance of a new mutation is

A random event

A group of birds are flying at sea. A storm strikes and only a few birds survive due to their wing structure. They land on an island and are able to find enough resources to reproduce. A scientists studies what happened and determines that this is the founder effect. Why is this not considered the founder effect?

All birds had an equal chance of survival

Which of the following is an example of sexual selection?

Bright colors of peacock feathers

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.

C

Whales, bony fishes, and cartilaginous fishes all have similar adaptations that enable them to live in the ocean. Figure 1 shows the phylogenetic relationship 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.

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 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.

The B blood type allele probably originated in Asia and subsequently spread to Europe and other regions of the world. This is an example of:

Gene flow

Which of the following generates the formation of adaptations?

Natural Selection

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 arrow?

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.

The pesticide DDT was widely used in the 1940s as a method of insect control. In the late 1950s the first DDT-resistant mosquitoes were discovered, and eventually DDT-resistant mosquitoes were found globally. When DDT is used now, the development of DDT resistance in mosquito populations occurs in months rather than years. Which of the following best explains the observations concerning DDT resistance in mosquitoes?

Natural selection favors DDT-resistant mosquitoes that are already present in a population when DDT exposure occurs

Over several years, bacteria were isolated from members of a human population and tested for antibiotic resistance. The percent of bacterial isolates that were found to be antibiotic resistant is presented in the graph above for each year of the study. Which of the following conclusions is best supported by the information presented in the graph?

Natural selection over multiple generations is favoring antibiotic resistance in the population of bacteria

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.

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 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.

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.

Which of the following is NOT an assumption made about a Hardy-Weinberg population in equilibrium?

There are an equal number of males in females in the population

All of the following are homologous structures EXCEPT:

butterfly wing and bat wing

All of the following are examples of evolution EXCEPT:

mutations in an individual

Matings between individuals from the two populations of Rhagoletis produce hybrid flies that appear to be healthy and have normal life spans. The eggs laid by these hybrid flies, however, hatch less often than those of flies from either of the two populations. What isolating mechanism seems to be important in this hybrid population?

reduced hybrid fertility

The condition in which there are barriers to successful interbreeding between individuals in the same community is referred to as:

reproductive isolation