IB 150 Practice Exam 3 Questions With Complete Solutions
A population of 500 jackrabbits has two alleles, FB and FW, for
a locus that codes for fur color. FBFB individuals have black
fur, FBFW individuals have gray fur,FWFW individuals have
white fur. 250 individuals are black, 150 individuals are gray
and 100 individuals are white. What are the observed genotype
frequencies in this population? Correct Answers 0.50, 0.30,
0.20
A researcher notices that in a certain moth species, some
females prefer to feed and lay eggs on domesticated plants like
potatoes and tomatoes. Other females prefer to feed and lay eggs
on wild plants. Both male and female moths primarily use scent
to find these plants from afar. Females tend to mate where they
feed, and the researcher finds a genetic basis for scent
preference in these moths. Based on the above information, what
might be occurring in this moth species? Correct Answers
divergence in sympatry
A small population of wolves was reintroduced to southern New
Mexico 20 years ago. Within the
population at that time were two different alleles (A1 and A2)
for a particular gene that affects coat color. A recent analysis
shows that there is only one allele (A2) in that population today,
after only three generations. Which of the following
mechanisms are potential reasons for this observation? Correct
Answers natural selection AND/OR genetic drift
A species of seagulls exists as a large number of different
populations on separate islands of the Azores archipelago. Both
, black and white gulls are present. The black-colored seagull is
due to a dominant allele (M). Mm and MM individuals are
black, and mm individuals are white. During a storm, two males
and two females are blown 300 miles West, to an isolated island
uninhabited by seagulls. They reproduce and found a new
population. They cannot disperse back to the original habitat,
nor can any new seagulls cross to the new island. Three of the
original colonists were white-colored gulls and one was black.
What is the frequency of the recessive (m) allele in this new
population? Correct Answers 0.875
A virus killed most of the seals in the North Sea (e.g., reduced
the population from 8000 to 800).
What is this an example of? Correct Answers population
bottleneck
a) Explain what inbreeding and assortative mating are.
b) Explain what the effect of both is on allele and genotype
frequencies, and why neither on their own would lead to
evolutionary change in the population.
c) Most individuals in the human population (the same is true
for many other species) are carriers of an estimated 7
recessive alleles that - if present in the homozygous
condition - would be fatal. Based on your answer to part (b)
above, suggest a hypothesis for how both inbreeding and
assortative mating might indirectly lead to enhanced
selection against recessive alleles in a population where
either inbreeding or assortative mating is frequent. Correct
Answers Essay:
A population of 500 jackrabbits has two alleles, FB and FW, for
a locus that codes for fur color. FBFB individuals have black
fur, FBFW individuals have gray fur,FWFW individuals have
white fur. 250 individuals are black, 150 individuals are gray
and 100 individuals are white. What are the observed genotype
frequencies in this population? Correct Answers 0.50, 0.30,
0.20
A researcher notices that in a certain moth species, some
females prefer to feed and lay eggs on domesticated plants like
potatoes and tomatoes. Other females prefer to feed and lay eggs
on wild plants. Both male and female moths primarily use scent
to find these plants from afar. Females tend to mate where they
feed, and the researcher finds a genetic basis for scent
preference in these moths. Based on the above information, what
might be occurring in this moth species? Correct Answers
divergence in sympatry
A small population of wolves was reintroduced to southern New
Mexico 20 years ago. Within the
population at that time were two different alleles (A1 and A2)
for a particular gene that affects coat color. A recent analysis
shows that there is only one allele (A2) in that population today,
after only three generations. Which of the following
mechanisms are potential reasons for this observation? Correct
Answers natural selection AND/OR genetic drift
A species of seagulls exists as a large number of different
populations on separate islands of the Azores archipelago. Both
, black and white gulls are present. The black-colored seagull is
due to a dominant allele (M). Mm and MM individuals are
black, and mm individuals are white. During a storm, two males
and two females are blown 300 miles West, to an isolated island
uninhabited by seagulls. They reproduce and found a new
population. They cannot disperse back to the original habitat,
nor can any new seagulls cross to the new island. Three of the
original colonists were white-colored gulls and one was black.
What is the frequency of the recessive (m) allele in this new
population? Correct Answers 0.875
A virus killed most of the seals in the North Sea (e.g., reduced
the population from 8000 to 800).
What is this an example of? Correct Answers population
bottleneck
a) Explain what inbreeding and assortative mating are.
b) Explain what the effect of both is on allele and genotype
frequencies, and why neither on their own would lead to
evolutionary change in the population.
c) Most individuals in the human population (the same is true
for many other species) are carriers of an estimated 7
recessive alleles that - if present in the homozygous
condition - would be fatal. Based on your answer to part (b)
above, suggest a hypothesis for how both inbreeding and
assortative mating might indirectly lead to enhanced
selection against recessive alleles in a population where
either inbreeding or assortative mating is frequent. Correct
Answers Essay:
