NAME:__________________________PERIOD:____DATE:________
Evolution of Populations
Completion On the lines provided, complete the following sentences.
1. The combined genetic information of all members of a particular population is called a(an)
________________________.
2. The ________________________ of an allele is the number of times that the allele occurs in
a gene pool, compared with the number of times other alleles occur.
3. A(An) ________________________ is a trait controlled by a single gene.
4. ________________________ are controlled by two or more genes.
5. The frequency of an allele in a population is often represented by a _____________________.
Multiple Choice On the line provided, write the letter of the answer that best completes the
sentence or answers the question.
____________ 6. For most genes, a gene pool typically contains
a. no alleles.
c. one allele.
b. two or more alleles.
d. no more than two alleles.
____________ 7. The graphs below show changes in the distribution of beak size in Galápagos finches during a
period when food was scarce. What type of natural selection do the graphs show?
a. directional selection
c. stabilizing selection
b. destabilizing selection
d. disruptive selection
____________ 8. The graph below shows the distribution of human birth weights. What type of selection keeps this
curve narrow and in the same place?
a. directional selection
c. stabilizing selection
b. destabilizing selection
d. disruptive selection
____________ 9. What type of natural selection takes place when individuals at the upper and lower
ends of the curve have higher fitness than individuals near the middle?
a. directional selection
c. stabilizing selection
b. destabilizing selection
d. disruptive selection
____________ 10. A random change in allele frequency is called
a. fitness.
c. speciation.
b. genetic drift.
d. the founder effect.
____________ 11. Genetic drift is more likely to occur in
a. large populations.
b. medium-sized populations.
c. small populations.
d. a single individual.
____________ 12. What occurs when allele frequencies change as a result of the migration of a small
subgroup of a population?
a. directional selection
c. speciation
b. the founder effect
d. genetic equilibrium
____________ 13. What principle states that the frequency of an allele in a population will remain
constant unless one or more factors cause that frequency to change?
a. the speciation principle
c. the Hardy-Weinberg principle
b. the genetic equilibrium principle
d. the genetic-drift principle
____________ 14. The situation in which allele frequencies do not change is called
a. genetic equilibrium.
c. behavioral equilibrium.
b. stabilizing equilibrium.
d. directional selection.
____________ 15. Which of the following is required to maintain genetic equilibrium?
a. The population must be small. c. Individuals move between populations.
b. No mutations occur.
d. Natural selection occurs.
____________ 16. What is the formation of a new species called?
a. directional selection
c. founder effect
b. speciation
d. temporal isolation
____________ 17. What situation occurs when members of two different species cannot interbreed and
produce fertile offspring?
a. reproductive isolation
c. genetic drift
b. genetic equilibrium
d. natural selection
____________ 18. What kind of isolation occurs when two populations are capable of interbreeding but
have differences in courtship rituals or other types of behavior?
a. courtship isolation
c. geographic isolation
b. behavioral isolation
d. temporal isolation
____________ 19. Two populations kept separate by a river are characterized by
a. genetic drift.
c. geographic isolation.
b. disruptive selection.
d. temporal isolation.
____________ 20. What situation occurs when two or more species reproduce at different times?
a. stabilizing selection
c. geographic isolation
b. behavioral isolation
d. temporal isolation
____________ 21. The flying squirrel of North America very closely resembles the flying sugar glider
of Australia. They are similar in size, have long, bushy tails, and thin folds that
allow them to glide through the air. The squirrel is a placental mammal while the
sugar glider is a marsupial. These close resemblances, even though genetically
geographically separated by great distances, can best be explained by:
a. convergent evolution
c. divergent evolution
b. spontaneous generation
d. vestigial structures
____________ 22. Hawaiian honeycreepers are a group of birds with similar body shapes and size. However they vary
greatly in color and beak shape. Each species occupies its own niche and is adapted to the foods
available in its niche. The evolution from a common ancestor to a variety of species is an example
of evolution form a common ancestor to a variety is an example of:
a. convergent evolution
c. vegetative propagation
b. cross-pollination
d. divergent evolution
____________ 23. Which combination of characteristics in a population would provide the greatest potential for
evolutionary change?
a. small population, few mutations
c. large population, few mutations
b. small population, many mutations
d. large population, many mutations
____________ 24. Mutations occur because of:
a. the introduction of new variations from elsewhere
b. the introduction of new variations through mistakes in DNA replication
c. the chance survival and reproduction of new variations
d. cells in the body dying off
Directions: Answer the following questions completely.
25. What is coevolution evolution?
26. Adaptive radiation is one example of divergent evolution. When does divergent evolution occur?
27. When will convergent evolution occur?