Bio 1A - Chapter 17 [Online Quiz]

A particular gene in a population has two alleles, C and c. If the allele frequency of C = 0.7, what is the frequency of c?

0.3

Consider a population that has reached its Hardy-Weinberg equilibrium frequencies. If this population is suddenly subjected to strong directional selection, both the allele and the genotype frequencies are likely to undergo change as a result.

True

The impact that a mutation has on a population depends largely on the environment in which the mutation occurs.

True

DDT resistance in mosquitoes is one dramatic example of the mode of natural selection known as

directional selection.

Sexual selection in a population

is a special type of natural selection.

A population susceptible to genetic bottlenecks would have which of the following characteristics?

small population size

Microevolution refers to

the changes in allele or genotype frequencies that occur in a population over time.

The genetic mutations that occur in organisms are

the raw material of evolution.

Which of the following contributes to the spread of antibiotic resistance among pathogenic bacteria?

the transfer of resistance genes between bacteria. poor sanitation in areas where pathogenic microbes are plentiful. indiscriminate use of antibiotics. directional selection

Which of the following statements about genetic variation is true?

Mutation is the ultimate source of new alleles.

If there are 1,000 individuals in a population and 600 of them are homozygous dominant for a gene that has only two alleles, what is the genotype frequency for the homozygous dominant condition?

0.6

Consider a population with a total of 500 alleles for a specific gene. How many individuals are in this population?

250

Of the organisms listed below, which one is not believed to have undergone a genetic bottleneck at some point in its recent evolutionary history?

Culex mosquitoes

A population of organisms has a gene for which there are two alleles, D and d. The allele frequency of D = 0.8. If this population satisfies all five of the Hardy-Weinberg conditions, what are the genotype frequencies that are expected in the next generation?

DD = 0.64; Dd = 0.32; dd = 0.04

The Hardy-Weinberg equation describes the genotype frequencies that will occur in an evolving population of organisms.

False

Which of the following statements about gene flow is true?

It reduces the genetic variation between populations.

In Figure 17.8 in your textbook, the survival of newborn humans is compared to their birth weight. Note that these data are from London and span the time period between 1935 and 1946. If you were to look at a graph of comparable data for the same population from the 1990s, what differences, if any, would you see?

There would be a broader optimum birth weight due to medical advances.

Refer to Figure 17.3 in your textbook. If the population of wildflowers in this hypothetical simulation of genetic drift were made up of 1000 individuals instead of 10, how would this affect the change in allele frequencies?

There would probably be a much smaller change in allele frequencies.

In the Hardy-Weinberg equation, the terms p and q represent the ________ in a population.

allele frequencies

In the Hardy-Weinberg equation, the term 2pq represents the

frequency of the heterozygous genotype.

Which of the following is more likely to occur when a population of organisms is small?

genetic drift

Several generations into the future, a population of birds currently undergoing stabilizing selection will look

more like the current mean.

A violation of which of the following conditions would cause a population to shift away from its stable Hardy-Weinberg frequencies?

no genetic drift. no gene flow. no net mutation. no natural selection

Which of the following is an example of rapid evolutionary change in a population?

pesticide resistance in insects