Microevolution and Changing Alleles
True and False Questions
In stabilizing selection, the extreme individuals in the population are the most fit.
Evolution is not always the result of natural selection.
According to the Hardy-Weinberg law, in the absence of forces acting to change allele frequencies, the proportions of genotypes in a population will remain constant from generation to generation.
If the frequencies of the A allele is p and the frequency of the a allele is q, then the Hardy-Weinberg frequency of Aa heterozygotes will be 2pq.
According to Hardy-Weinberg equilibrium, 1 = p2 + 2pq + q2.
The founder effect is when a population has been 1st established by a few individuals with an unusual genetic constitution.
Genetic drift is usually an important factor in populations with a large number of individuals.
Multiple Choice Questions - Choose the best available answer.
Which of the following is not an assumption of the Hardy-Weinberg principle?
a) mating must be random.
b) no selection can be operating on the population.
c) the gene pool must have balanced polymorphism.
d) populations must be large.
e) there must be no mutation.
Which is an accurate statement regarding allele frequencies?
a) The values of allele frequencies are always between 0 and 1.
b) Allele frequencies are always values greater than 1.
c) In considering evolution, allele frequencies do not change.
d) Allele frequencies are the same as genotypic proportions.
A plant population is 50% BB and 50% bb. After random mating among all these individuals, we expect
a) the F1 to be 100% Bb
b) the F1 to be 50% BB and 50% bb
c) the F1 to be 25% BB, 50% Bb, and 25% bb
d) the F1 to be randomly composed of BB, Bb, and bb individuals
A butterfly population has a rare homozygous recessive form ww that occurs at a frequency of 0.0004. The population is in Hardy-Weinberg equilibrium for the trait. What is the frequency of the homozygous dominant form?
The type of natural selection that would favor individuals near the mean and select against extremes is
a) stabilizing selection
b) directional selection
c) disruptive selection
d) artificial selection
Genetic drift is most likely to be an important evolutionary force in
a) artificial populations
b) natural populations
c) very small populations
d) very large populations
Elephant seals were common in the early 19th century but were hunted almost to extinction. Today their numbers have increased again, but the species has little genetic variation. We can say the species has experienced
a) natural selection
b) mutation pressure
c) a bottleneck
d) founder effect
Which of the following would argue that much variation at the molecular level is due to genetic drift?
e) Punctuated equilibriumists
Traditionally, human males with the genetic disease hemophilia often died before they reached reproductive age. If modern medical treatment allows most hemophiliacs to lead long and fruitful lives, what will happen to the frequency of the allele responsible for hemophilia?
a) It should increase in frequency.
b) It should decrease in frequency.
c) It should not change in frequency.
d) Change in frequency will be unpredictable due to random events.
One Point Each:
Which of the following is not consistent with our understanding of the cell.
a) DNA can make DNA.
b) DNA can make protein directly.
c) mitochondria have DNA.
d) chloroplasts have DNA.
e) prokaryotes lack a nuclear membrane.
Which of the following is not consistent with the endosymbiotic hypothesis?
a) blue green algae (cyanobacteria) evolved to become chloroplasts
b) a flagellated prokaryote evolved to become cilia
c) aerobic bacteria evolved to become mitochondria
d) ribosomes evolved in eukaryotic cells
e) mitochondria and chloroplasts reproduced by simple fission (pinching in two)
You have: answers correct out of a possible eighteen.
The question numbers that were not correct are:
Instructor: Professor Clyde Herreid, firstname.lastname@example.org