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Bio I Ch. 16 Test B

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 1. 
The combined genetic information of all members of a particular population is the population’s
a.
relative frequency.
c.
genotype.
b.
phenotype.
d.
gene pool.
 

 2. 
A change in a sequence of DNA is called a
a.
recombination.
c.
single-gene trait.
b.
polygenic trait.
d.
mutation.
 

 3. 
The two main sources of genetic variation are
a.
genotypes and phenotypes.
b.
gene shuffling and mutations.
c.
single-gene traits and polygenic traits.
d.
directional selection and disruptive selection.
 

 4. 
An example of a single-gene trait is
a.
a widow’s peak in humans.
b.
the weight of human infants at birth.
c.
height in humans.
d.
beak size in the Galápagos finches.
 

 5. 
The number of phenotypes produced for a given trait depends upon
a.
the number of genes that control the trait.
b.
which form of the trait is dominant.
c.
the relative frequencies of the various alleles.
d.
whether or not natural selection is at work.
 

 6. 
The distribution of phenotypes for a typical polygenic trait can often be expressed as
a.
a bar graph.
c.
Mendelian ratios.
b.
a bell-shaped curve.
d.
allele frequencies.
 

 7. 
Natural selection acts directly on
a.
alleles.
c.
phenotypes.
b.
genes.
d.
mutations.
 

 8. 
Which of the following is NOT a way in which natural selection affects the distribution of phenotypes?
a.
directional selection
c.
disruptive selection
b.
stabilizing selection
d.
chance events
 

 9. 
In genetic drift, allele frequencies change because of
a.
mutations.
c.
natural selection.
b.
chance.
d.
genetic equilibrium.
 

 10. 
Which of the following events do biologists consider a random change?
a.
directional selection
c.
disruptive selection
b.
speciation
d.
genetic drift
 

 11. 
The situation in which allele frequencies of a population remain constant is called
a.
evolution.
c.
genetic equilibrium.
b.
genetic drift.
d.
natural selection.
 

 12. 
One of the conditions required to maintain genetic equilibrium is
a.
natural selection.
b.
mutations.
c.
nonrandom mating.
d.
no movement into or out of the population.
 

 13. 
The separation of populations by barriers such as rivers, mountains, or bodies of water is called
a.
temporal isolation.
c.
behavioral isolation.
b.
geographic isolation.
d.
genetic equilibrium.
 

 14. 
A factor that is necessary for the formation of a new species is
a.
reproduction at different times.
b.
geographic barriers.
c.
different mating behaviors.
d.
reproductive isolation.
 

 15. 
Which is the first step that occurred in the speciation of the Galápagos finches?
a.
establishment of genetic equilibrium
c.
ecological competition
b.
behavioral isolation
d.
arrival of the founding population
 

Completion
Complete each statement. Word bank. You must spell the word correctly to count! Spell it exactly as it is in the word bank!
Hardy-Weinberg
single-gene
reproductively
alleles
polygenic
 

 16. 
A gene pool typically contains two or more ____________________ for each gene.
 

 

 17. 
Inheritable traits can be classified as either ____________________ traits or polygenic traits.
 

 

 18. 
For ____________________ traits, natural selection can affect the distribution of phenotypes in three ways.
 

 

 19. 
According to the _________________________ principle, allele frequencies in a population will remain constant unless one or more of five specific factors cause those frequencies to change.
 

 

 20. 
For new species to evolve, populations must be ____________________ isolated from each other.
 

 



 
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