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Bio I Ch. 16 Test A

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

 1. 
Which of the following statements describes what all members of a population share?
a.
They are temporally isolated from one another.
b.
They are geographically isolated from one another.
c.
They are members of the same species.
d.
They have identical genes.
 

 2. 
Which statement about gene pools is typically true?
a.
They contain two or more alleles for each gene.
b.
They contain only dominant alleles.
c.
They belong to two or more interbreeding species.
d.
The relative frequencies of the alleles never change.
 

 3. 
If an allele makes up one fourth of a population’s alleles for a given trait, its relative frequency is
a.
100 percent.
c.
25 percent.
b.
75 percent.
d.
4 percent.
 

 4. 
In many kinds of organisms, most heritable differences are due to
a.
mutations during gamete formation.
b.
chemicals in the environment.
c.
gene shuffling during gamete formation.
d.
the effects of radiation.
 

 5. 
Gene shuffling includes the independent movement of chromosomes during meiosis as well as
a.
mutations from radiation.
b.
changes in the frequencies of alleles.
c.
crossing-over.
d.
mutations from chemicals.
 

 6. 
A single-gene trait that has two alleles and that shows a simple dominant-recessive pattern will result in
a.
one phenotype.
c.
four phenotypes.
b.
two phenotypes.
d.
millions of phenotypes.
 

 7. 
When individuals at only one end of a bell-shaped curve of phenotype frequencies have high fitness, the result is
a.
directional selection.
c.
disruptive selection.
b.
stabilizing selection.
d.
genetic drift.
 

 8. 
When individuals with an average form of a trait have the highest fitness, the result is
a.
not predictable.
c.
directional selection.
b.
disruptive selection.
d.
stabilizing selection.
 

 9. 
Genetic drift tends to occur in populations that
a.
are very large.
b.
are small.
c.
are formed from new species.
d.
have unchanging allele frequencies.
 

 10. 
The type of genetic drift that follows the colonization of a new habitat by a small group of individuals is called
a.
the Hardy-Weinberg principle.
c.
directional selection.
b.
the founder effect.
d.
stabilizing selection.
 

 11. 
The genetic equilibrium of a population can be disturbed by each of the following EXCEPT
a.
nonrandom mating.
b.
movement into and out of the population.
c.
a large population size.
d.
mutations.
 

 12. 
The allele frequencies of a population are more likely to remain unchanged if
a.
the population size is reduced.
b.
frequent movement into and out of the population occurs.
c.
all mating is random.
d.
the mutation rate increases.
 

 13. 
What situation might develop in a population having some plants whose flowers open at midday and other plants whose flowers open late in the day?
a.
behavioral isolation
c.
temporal isolation
b.
geographic isolation
d.
genetic drift
 

 14. 
The Galápagos finch species are an excellent example of
a.
speciation.
c.
stabilizing selection.
b.
genetic equilibrium.
d.
selection on single-gene traits.
 

 15. 
What did Peter and Rosemary Grant learn about mate choice in the Galápagos finches?
a.
Phenotype plays no role in mate choice.
b.
Genotype plays no role in mate choice.
c.
Finches prefer mates with smaller beaks than their own.
d.
Finches prefer mates with beaks similar in size to their own.
 

Completion
Complete each statement. Word bank. Words must be spelled correctly or they will be wrong. Spell them like they are in this bank!
genetic equalibrium
gametes
directional
phenotypes
 

 16. 
Crossing-over can occur during the meiotic divisions that produce cells called ____________________.
 

 

 17. 
A polygenic trait can have many possible genotypes and ____________________.
 

 

 18. 
When the phenotypes of polygenic traits are represented by a bell-shaped curve, the ____________________ of individuals close together on the curve is not very different.
 

 

 19. 
When a population is NOT evolving, it is in a situation called _________________________.
 

 

 20. 
In the Galápagos finches that Rosemary and Peter Grant studied, a pattern of natural selection called ____________________ selection favored individuals with larger, heavier beaks during a drought.
 

 



 
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