Evolution as Genetic Change
Slide 4
What can be inferred from the information in the table?
(A) Diversity in the gene pool increased over time.
(B) Allele B was dominant in 1910 but became recessive over time.
(C) The population was in genetic equilibrium during this time period.
(D) The probability of genotype Bb increased over time.
(E) The likelihood of surviving and reproducing became higher for individuals with Allele b than for individuals with Allele B.
(E) The likelihood of surviving and reproducing became higher for individuals with Allele b than for individuals with Allele B.
Western and Eastern meadowlarks look very similar and it is difficult to tell them apart, until they sing. Their mating songs are quite different. The Western meadowlark has a melodious song, whereas the song of the Eastern meadowlark sounds more like a whistle. Even though their ranges overlap in the central United States, they do not interbreed and are considered two different species. How would speciation MOST LIKELY have occurred in these two species of meadowlarks?
(A) Reproductive isolation occurred through behavioral isolation.
(B) Reproductive isolation occurred through temporal isolation.
(C) Populations were separated through geographical isolation.
(D) Populations were separated through competition.
(A) Reproductive isolation occurred through behavioral isolation.
True or False
In words, the Hardy-Weinberg equation states that
the frequency of the homozygous dominant allele + the frequency of the heterozygous allele + the frequency of the homozygous recessive allele = 100%
True
Scientists want to estimate the time when two species began evolving separately from a common ancestor. What would be the MOST useful strategy for calculating this estimate?
(A) comparing DNA sequences from each species for the same gene
(B) comparing DNA sequences from each species for different genes
(C) comparing the length, size, or weight of an average member of each species
(D) identifying the traits of the common ancestor
(E) identifying the genetic diversity of each species
(A) comparing DNA sequences from each species for the same gene
Slide 3
Which statements are supported by the data in the table? Choose three correct answers.
(A) Stick insects actively choose to live in an environment where they are camouflaged.
(B) Depending on the environment they live in, the green, brown, or yellow-green stick insects have an advantage over organisms that are easier to detect by predators.
(C) Stick insects will be less likely to survive and reproduce if they are more visible to predators like the blue jays.
(D) Depending on the environment they live in, the allele frequency for their body color may decrease or increase over time.
(E) Stick insects will be more likely to survive and reproduce if they avoid an environment that matches their body color.
(B) Depending on the environment they live in, the green, brown, or yellow-green stick insects have an advantage over organisms that are easier to detect by predators.
(C) Stick insects will be less likely to survive and reproduce if they are more visible to predators like the blue jays.
(D) Depending on the environment they live in, the allele frequency for their body color may decrease or increase over time.
Several steps led to the evolution of 13 different finch species on the Galápagos Islands. Which is one of these steps?
(A) After the founder finches arrived, their gene pool was passed intact to all of the following generations.
(B) Finch populations on each island interbred regularly with populations on other islands.
(C) Thirteen groups of founder finches arrived on all of the Galápagos Islands at various times.
(D) Changes in gene pools occurred as the finch populations adapted to the specific environment of each island.
(D) Changes in gene pools occurred as the finch populations adapted to the specific environment of each island.
According to the Hardy-Weinberg principle, the frequencies of alleles remain constant in a population, but only under certain conditions. Which of these events or conditions is MOST LIKELY to maintain Hardy-Weinberg equilibrium?
(A) A natural disaster reduces the population to about 20 percent of its previous size.
(B) Immigration from a neighboring ecosystem increases the population by 50 percent.
(C) The alleles have no effect on which males and females mate and produce offspring.
(D) The arrival of a new predator makes one of the alleles more advantageous than the other allele.
(C) The alleles have no effect on which males and females mate and produce offspring.
What is best describes the role of mutations in evolution?
A. Mutations are not necessary for evolution because they are not heritable.
B. Mutations are useful for evolution to occur because they promote genetic uniformity within a population.
C. Mutations are essential for evolution to occur because they produce genetic variations within a population.
D. Mutations are essential for evolution to occur because they are responses to environmental changes.
C. Mutations are essential for evolution to occur because they produce genetic variations within a population.
Slide 5
The graphs below show the changes in crab color at one beach.
Which of the following is most likely to have caused the change in the distribution?
(A) A new predator arrived that preferred dark-tan crabs.
(B) A new predator arrived that preferred light-tan crabs.
(C) A new predator arrived that preferred medium-tan crabs.
(D) A change in beach color made medium-tan crabs the most visible to predators.
(E) A change in beach color made light-tan crabs the most visible to predators.
(D) A change in beach color made medium-tan crabs the most visible to predators.
Several species of leopard frogs are common throughout North America, where their ranges overlap. Different species of leopard frogs are very similar in appearance, but the males of each species have a unique courtship call. How did speciation MOST LIKELY occur in leopard frogs?
(A) Reproductive isolation occurred through behavioral isolation.
(B) Reproductive isolation occurred through temporal isolation.
(C) Populations were separated through geographical isolation.
(D) Populations were separated through competition.
(A) Reproductive isolation occurred through behavioral isolation.
The Hardy-Weinberg principle predicts that five conditions can disturb genetic equilibrium and cause evolution to occur. Which of the following is not one of those principles?
(A) Random mating
(B) Small population size
(C) Gene flow from immigration or emigration
(D) Mutations
(E) Natural Selection
(A) Random mating
Slide 8
In insects, a Hox gene called Ubx controls the development of legs in the abdomen.
Which is the most likely result if the Ubx gene was activated either before or after it is normally activated in the sequence of Hox gene expression?
(A) The insect develops either shorter or longer abdominal legs.
(B) The insect develops normal body parts at either a slower or more rapid rate.
(C) The insect develops normal body parts but in an altered time sequence.
(D) The insect develops legs in other parts of its body.
(D) The insect develops legs in other parts of its body.
Slide 6
In a population of goats, both beige-coated and brown-coated goats are better able to blend with the rocky environment than white-coated goats. In this case, the beige and brown coat colors are favored by natural selection over the white color.
Which type of pattern of natural selection would occur in this scenario?
(A)
(B)
(C)
(D)
(C)
(Slide 2)
Five closely related species of frogs live in ranges that overlap. Some breed in woodland ponds, some in lowland swamps, and some in streams. How do these five species of frogs remain separate and do not attempt to mate?
Study the graph and the text to identify two modes of isolation.
(A) Temporal isolation
(B) Behavioral isolation
(C) Geographical isolation
(D) Reproductive isolation
(A) Temporal isolation
(C) Geographical isolation
In cattle, the allele for red coat color (R) shows incomplete dominance over the allele for white (R’) coat color. The hybrid (RR’) is roan coat color, which is a mixture of red and white hairs.
In a population of cattle, 32 percent of the population is roan color. What are the frequencies of the allele for red coat color (R) and white coat color (R’)? Assume that the conditions of Hardy-Weinberg equilibrium apply to the population.
(A) R = 0.50; R’ = 0.50
(B) R = 0.65; R’ = 0.35
(C) R = 0.75; R’ = 0.25
(D) R = 0.80; R’ = 0.20
(D) R = 0.80; R’ = 0.20
Slide 7
Study the graph to see how grasshoppers of three different body colors survive predation by blue jays in a mostly green environment. Grasshopper numbers are shown before and after blue jays preyed on them.
Which statements are supported by the data in the table? Choose three correct answers.
(A) If brown grasshoppers are more visible to blue jay predators in green environments, they might be less likely to reproduce, and the allele for brown color will be become less common.
(B) If green grasshoppers are less visible to blue jay predators in green environments, they will be more likely to reproduce, and the allele frequency for green color will increase.
(C) If natural selection produces changes in the allele frequencies of yellow-green grasshoppers in the green environment, there will be fewer of them.
(D) If grasshoppers avoid an environment that matches their body color, they will be more likely to survive and reproduce successfully.
(A) If brown grasshoppers are more visible to blue jay predators in green environments, they might be less likely to reproduce, and the allele for brown color will be become less common.
(B) If green grasshoppers are less visible to blue jay predators in green environments, they will be more likely to reproduce, and the allele frequency for green color will increase.
(C) If natural selection produces changes in the allele frequencies of yellow-green grasshoppers in the green environment, there will be fewer of them.
Natural and artificial selection depend on genetic and phenotypic variation. In natural selection the selective pressure comes from the environment and in artificial selection it comes from the human breeder. Suppose a breeder of pigeons has a population of birds with pigmented feathers that range from light to intermediate to dark. She selectively breeds the pigeons with intermediate pigmentation.
After several generations, what pattern of evolutionary change will occur?
(A) disruptive selection, in which pigeons with dark pigmentation are favored.
(B) stabilizing selection, in which pigeons with intermediate pigmentation are favored.
(C) directional selection, in which pigeons with dark pigmentation are favored.
(D) directional selection, in which pigeons with intermediate pigmentation are favored.
(E) disruptive selection, in which pigeons with light and dark pigmentation are favored.
(B) stabilizing selection, in which pigeons with intermediate pigmentation are favored.
Scientists want to estimate the time when two species began evolving separately from a common ancestor. What would be the MOST useful strategy for calculating this estimate?
(A) comparing DNA sequences from each species for the same gene
(B) comparing DNA sequences from each species for different genes
(C) comparing the length, size, or weight of an average member of each species
(D) identifying the traits of the common ancestor
(E) identifying the genetic diversity of each species
(A) comparing DNA sequences from each species for the same gene
A geneticist collected data of a population of mice. Of the 50 mice, 12 were homozygous black (BB), 24 were heterozygous black (Bb) and 14 were brown (bb).
What are the allele frequencies for this population?
(A) B = 0.32; b = 0.68
(B) B = 0.36; b = 0.64
(C) B = 0.48; b = 0.52
(D) B = 0.45; b = 0.55
(C) B = 0.48; b = 0.52
As Darwin explained, a small population of finches settled on the Galapagos Islands. Darwin called these finches the founders, or founding population. The founders became the ancestors of all the finch species that Darwin observed on the islands.
How did the founders compare with other finches of the same species that remained in South America?
(A) They were essentially identical, and had the same allele frequencies.
(B) They were similar, but might have had different allele frequencies due to the small size of the founding population.
(C) They were very different, because the founders were able to fly across the ocean.
(D) They were very different, because the founders had a much greater genetic diversity.
(B) They were similar, but might have had different allele frequencies due to the small size of the founding population.