AP Biology: Chapter 15

A small population of sawflies that was once connected to a larger one but is now isolated is no longer experiencing

gene flow.

Migration of moths is most likely to lead to

gene flow.

Red hair may have evolved in Neanderthals and then was introduced into human populations via interbreeding. If this is true, this would be an example of

gene flow.

A sample of 200 individuals from a population of blister beetles has 105 individuals that are GG for the G locus, 70 that are Gg, and 25 that are gg. The population

has a deficiency of 14% heterozygotes.

A Hardy-Weinberg analysis can be useful in studying a population of organisms known to be undergoing evolutionary change, because it can

help biologists identify specific processes of evolutionary change at work on the population.

Calculate the frequency of homozygotes for an allele at a locus in a population at Hardy-Weinberg equilibrium if the frequency of the allele is 0.15. One other allele is present in this population.

0.0225

If a population with two alleles is at Hardy-Weinberg equilibrium and the frequency of one allele is 0.7, what is the heterozygote frequency?

0.42

The FY3 gene plays a role in immune responses in flies. In one population, there are two alleles, and the frequency of one allele is 0.60. If the population is at Hardy-Weinberg equilibrium, what is the frequency of heterozygotes?

0.48

A genetic locus has two alleles. One has a frequency of 0.12; the other has a frequency of _______.

0.88

You discover a population of guppies and find it to be at Hardy-Weinberg equilibrium with respect to the S locus. Suppose there are two alleles at this locus, and the frequency of one of those alleles (the s allele) is 0.40. Of the individuals that carry at least one s allele, what fraction are homozygotes?

1/4

The frequency of an allele in a population of manatees is 0.15. If the population is at Hardy-Weinberg for this locus, what number of 600 individuals should be homozygous for this allele?

13.5

The FY3 gene plays a role in immune responses in flies. In one population, there are two alleles, and the frequency of one allele is 0.80. If the population is at Hardy-Weinberg equilibrium, how many homozygotes for the most common allele should we observe in a sample of 250 individuals?

160

What is the maximum number of alleles that a given human adult (with 23 pairs of chromosomes) can have at any particular genetic locus?

2

You discover a population of seals and find it to be at Hardy-Weinberg equilibrium with respect to the A locus. Suppose that there are two alleles at this locus and the frequency of one of those alleles (the a-6 allele) is 0.4. Of the individuals that carry at least one a-6 allele, what percent are homozygotes?

25

If the frequency of the A3 allele of a creatine phosphatase locus in a population of lions is 0.4, how many copies of that allele should we expect to see in a population of 500 lions?

400

If the frequency of an allele is 0.75, how many copies of this allele should be in a population of 300 diploid individuals?

450

How many copies of alleles for a single locus are in a population of 300 panthers?

600

Which statement about Hardy-Weinberg equilibrium is false?

A population can be said to be evolving if it can be shown to be approaching Hardy-Weinberg equilibrium.

1. Height in humans is influenced by numerous loci and has a relatively smooth distribution. It is thus a _______ or _______ trait. a. quantitative; discrete b. quantitative; continuous c. qualitative; continuous d. qualitative; discrete e. qualitative; heritable

ANSWER: B

5. Which type of selection is most likely to result in an evolutionary trend? a. Stabilizing b. Directional c. Disruptive d. Purifying e. Artificial

ANSWER: B

6. Suppose individual robins that have longer beaks have somewhat more offspring than those with shorter beaks, and that this has led to increases in beak length over time. We can say that beak size is associated with the _______ of the robin, and that there is _______ selection operating on beak size. a. fitness; stabilizing b. fitness; directional c. genetic structure; stabilizing d. genetic structure; directional e. genetic structure; disruptive

ANSWER: B

2. Whether a fly has white or red eyes is due to alleles at a single locus. It is thus a _______ or _______ trait. a. quantitative; discrete b. quantitative; continuous c. qualitative; discrete d. qualitative; continuous e. heritable; continuous

ANSWER: C

Who besides Darwin deserves credit for formulating evolution by natural selection?

Alfred Russel Wallace

The Hardy-Weinberg equilibrium is not applicable under which condition?

Asexual reproduction

There are three isolated populations of orchids. Population A has had a constant size of about 40,000. Population B has had a constant size of about 14,000. Population C has had a constant size of about 300. We most expect to see an increase in the frequency of deleterious alleles in population _______, because this population would experience the _______ genetic drift.

C; most

Which statement would best exemplify Lyell's ideas that led Darwin to formulate his views on evolution?

Coastline formation has occurred slowly enough to be almost imperceptible, but it can operate over vast spans of time, even many millions of years.

Why do most scientists and historians give Darwin more credit than Wallace regarding their contributions to evolutionary theory?

Darwin provided more extensive evidence in support of evolution.

Which of the following statements about mutations is true?

Environmental changes can make a previously neutral mutation advantageous.

Which statement best explains the concept of natural selection?

Environmental conditions can impose pressures that lead to increased survival of some individuals over others in a population because of differences in their traits

Which is not an idea put forth by Darwin?

Evolution is a process of change in the genetic composition of a population.

Which statement about evolution is false?

Evolution is goal-directed.

Which statement about evolution is false?

Individuals evolve.

Which statement about Hardy-Weinberg equilibrium is false?

It assumes that individuals prefer to mate with individuals with certain genotypes.

Which statement about genetic drift as an evolutionary factor is true?

It is more significant in a population with small numbers than in a population with large numbers.

Which evolutionary process creates new genetic variation?

Mutation

Which statement about mutations is true?

Mutations are random with respect to the adaptive needs of organisms.

Which evolutionary process adapts populations to their environments?

Natural selection

Refer to the table below. mc011-1.jpg A biologist is studying four different populations of a bird species. The biologist made population counts during a mating season in which males and females mate multiple times. The data collected from this study are shown in the table above. Which population is likely to experience the greatest change in allele frequency from this generation to the next?

Population 3

Refer to the table below. mc013-1.jpg Several populations of mustard plants are sampled for variation at the F locus. The percentage of each genotype for Populations A, B, and C are summarized in the table above. Which population (or populations) shows a heterozygote deficiency?

Population C

Suppose a hard frost in southern Florida kills nearly all of a population of plants. Even though the plant population recovers in numbers after a couple of decades, the genetic variation within that population remains much reduced. What is the most likely cause of the diminished genetic variation?

Population bottleneck

Which phenomenon is not an evolutionary mechanism?

Random mating

What was Darwin's explanation for the evolution of bright colors and other apparently useless (and potentially deleterious) but conspicuous characters in males of many species?

Sexual selection

Which is not a condition that must be met for a population to be at Hardy-Weinberg equilibrium?

Small population size

Which is not a condition for a population to be at Hardy-Weinberg equilibrium?

Some genotypes survive better than others.

How does genetic drift compare to natural selection in its affects on a population?

The change in allele frequency by genetic drift is random, while change in allele frequency by natural selection is predictable.

Which statement about sexual selection is true?

Traits favored by sexual selection are often costly to males.

Different forms of the same gene are known as

alleles.

Refer to the figure below. mc004-1.jpg This graph was made by plotting the total number of mutations that accumulated in a population of bacteria over many generations. It can be inferred that mutations within a population accumulate

at a constant rate over many generations.

According to its scientific definition, a theory is

based on a large body of knowledge.

Three different alleles (c1, c2, and c3) at the c locus exist in a hypothetical population of juniper trees. If the frequency of c1 is 0.3, the frequency of c2

cannot be greater than 0.7.

In explaining what we now call evolution, Darwin often used the phrase "descent with modification." Fundamental to this idea is that

divergent species share a common ancestor.

The primary distinction between artificial selection and natural selection is that artificial selection _______, while natural selection _______.

involves purpose; does not

Small populations are _______ likely to be near Hardy-Weinberg equilibrium than large populations, because genetic drift is _______ important in small populations.

less; more

Deviations from Hardy-Weinberg equilibrium

occur when evolutionary forces are operating on the population.

Mistakes in the replication of DNA

provide genetic variation.

Darwin's breeding of pigeons

showed that breeding can produce a great deal of variation in traits.

Natural selection can be defined as

the differential survival and reproduction of individuals.

A windstorm transports a gravid fly to an island. Having only a small subset of the genetic variation in the mainland population, the offspring of this fly are somewhat different from the mainland population. This is an example of

the founder effect.