BIOLOGY EXAM #2 QUESTIONS AND
ANSWERS
Which of the following examples of natural selection in action would tend to increase
the genetic variation in the population?
Alpine skypilots evolve large flowers above the timberline and small flowers below
the timberline.
Natural selection causes dragonflies to evolve longer tails.
Natural selection simultaneously selects against heavy field mice (they starve during
winter) and light field mice (they freeze during winter).
Natural selection acts on beak size in finches such that those individuals able to eat
small, soft seeds survive through the winter. - Answer-Alpine skypilots evolve large
flowers above the timberline and small flowers below the timberline.
Which of the following is associated with inbreeding?
Individual plants self-fertilize.
Allele frequencies change in a population.
The frequency of homozygotes decreases in a population.
Individuals in a population experience depression. - Answer-Individual plants self-
fertilize.
The Hardy-Weinberg principle describes the relationship between allele and
genotypic frequencies under what conditions? - Answer-When none of the four
evolutionary forces is acting
Which scenario illustrates heterozygote advantage? - Answer-Individuals who are
heterozygous at a given locus are more fit than individuals who are homozygous at
the same locus.
Which variable is likely to undergo the largest change in value resulting from a
mutation that introduces a new allele into a population at a locus for which all
individuals formerly had been fully homozygous? - Answer-Average heterozygosity
Which pattern observed in natural populations is caused by a genetic bottleneck? -
Answer-Fixed loci in endangered plant populations
In some jacana species, males take care of the eggs and young, and females
compete among themselves for territories that contain one to several males. Female
jacanas are significantly larger than males. Which of these statements would you
predict to be true of this bird species?
ANSWERS
Which of the following examples of natural selection in action would tend to increase
the genetic variation in the population?
Alpine skypilots evolve large flowers above the timberline and small flowers below
the timberline.
Natural selection causes dragonflies to evolve longer tails.
Natural selection simultaneously selects against heavy field mice (they starve during
winter) and light field mice (they freeze during winter).
Natural selection acts on beak size in finches such that those individuals able to eat
small, soft seeds survive through the winter. - Answer-Alpine skypilots evolve large
flowers above the timberline and small flowers below the timberline.
Which of the following is associated with inbreeding?
Individual plants self-fertilize.
Allele frequencies change in a population.
The frequency of homozygotes decreases in a population.
Individuals in a population experience depression. - Answer-Individual plants self-
fertilize.
The Hardy-Weinberg principle describes the relationship between allele and
genotypic frequencies under what conditions? - Answer-When none of the four
evolutionary forces is acting
Which scenario illustrates heterozygote advantage? - Answer-Individuals who are
heterozygous at a given locus are more fit than individuals who are homozygous at
the same locus.
Which variable is likely to undergo the largest change in value resulting from a
mutation that introduces a new allele into a population at a locus for which all
individuals formerly had been fully homozygous? - Answer-Average heterozygosity
Which pattern observed in natural populations is caused by a genetic bottleneck? -
Answer-Fixed loci in endangered plant populations
In some jacana species, males take care of the eggs and young, and females
compete among themselves for territories that contain one to several males. Female
jacanas are significantly larger than males. Which of these statements would you
predict to be true of this bird species?
