Download Evolution of Populations

Evolution of Populations
EXAM
Multiple Choice: Select the letter that best answers each question.
1. Evolution is best described as:
a. any change in the sequence of an organism’s DNA
b. any change in the relative frequency of alleles in a population
c. the result of populations who have been isolated from one another
d. the result of the loss of a food source in an area
2. Differences among individuals of the same species are
referred to as:
a. mutations
c. natural selection
b. adaptations
d. variations
3. Evolutionary ‘fitness’ is:
a. the ability of the biggest, fastest organisms to survive
b. a measure of an individuals ability to produce reproductive offspring
c. an organism’s ability to adapt to a specific environmental pressure
d. a perfect set of genes with no mutations present
4. In fruit flies with the curly wing mutation, the wings will be straight if the
flies are kept at 16° Celsius. The most probable explanation for this is that:
a.
b.
c.
d.
fruit flies with curly wings cannot survive at high temperatures
the environment influences wing phenotype in these fruit flies
height temperatures increases the rate of mutations
wing length in these fruit flies is directly proportional to temperature
5. No change in the relative proportions of alleles in the gene pool is the HardyWeinberg definition of
a. genetic equilibrium
c. fitness
b. evolution
d. the founder effect
The diagram below shows the distribution of wing length in a population of
dragonflies. Use it to answer questions 6 & 7.
short
wing length
medium
long
wing length
wing length
6. On the diagram, draw a dotted line indicating the new population distribution
after a directional selection has occurred in favor of short wing length.
7. If a large population of bullfrogs moved into the dragonflies’ habitat and
began feeding primarily on medium-winged dragonflies, what type of selection
might occur?
8. A change in a gene pool simply by chance, rather than natural selection, can
be caused by:
a. disruptive selection
b. behavioral isolation
c. ecological competition
d. genetic drift
9. Charles Darwin was the first to develop the theory of evolution by studying
the various species of organisms living on the Galapagos Islands. However,
his research was somewhat hindered because he did not have a clear
understanding of:
a.
a.
b.
c.
exactly how traits were passed from parent to offspring
the dynamics of ecological competition
the Hardy-Weinberg principle
the effects of isolating mechanisms on populations
10. If two or more species reproduce at different times, it can lead to:
a. genetic drift
c. decreased gene frequency
b. directional selection
d. temporal isolation
11. How many alleles are present for a single-gene trait?
a. one
b. two
c. many more than two
d. greater than two, but never greater than ten
12. An evolutionary adaptation that increases an individual’s ability to pass
along its genes can be:
a.
b.
c.
d.
e.
an anatomical change
a physical change
a behavioral change
any of these
none of these
13. If two populations of a single species become isolated by a geographical
barrier they may begin to diverge genetically. Which of the following processes
will not contribute to this divergence?
a. genetic drift
c. gene flow
b. mutation
d. selection
14. Individuals are unquestionably members of the same species if they:
a. possess the same number of chromosomes.
b. breed at the same time.
c. are phenotypically indistinguishable.
d. can mate and produce fertile offspring.
15.Because a founder’s colony is only a small representation of the parent
population from which it came, it often suffers from:
a. geographical isolation
c. a lack of genetic diversity
b. increased genetic diversity
d. genetic equilibrium
Below is a diagram showing the distribution of fur color on a population of
mice. The dotted line represents the distribution of fur colors before being
subjected to a specific environmental pressure, while the solid line represents
the distribution of fur colors AFTER exposure to environmental pressure. After
studying the graph, answer questions 16 & 17.
white mice
brown mice
black mice
16. What type of natural selection is represented by the new curve?
17. Formulate a possible environmental pressure that could have caused this
type of selection to occur.
18. The first step in speciation in animals is usually
a. random mating among individuals within a population
b. gene mutations that lead to an altered offspring
c. formation of very large, uncontrolled population
d. a separation of the gene pools of two populations
19. A type of natural selection that acts most strongly against individuals of an
intermediate type is called:
a. disruptive selection
b. stabilizing selection
c. unnatural selection
d. directional selection
20. When members of the same or different species fight over resources such as
food, mates, or habitat, it is called:
a. continued evolution
b. genetic drift
c. geographic isolation
d. ecological competition
21. Two populations that are capable of interbreeding but do not because of
differences in courtship rituals is an example of:
a. geographic isolation
c. temporal isolation
b. behavioral isolation
d. the Hardy-Weinberg effect
22. What are the two main sources of genetic variation?
a. mutations and gene shuffling
c. traits and gene shuffling
b. radiation and alleles
d. genes and viability
23. Polygenic traits produce a range of phenotypes that often fit a:
a. bell-shaped curve
b. downward-sloped graph
c. irregular curve
d. upward-sloped graph
24. Which of the following is one of the five conditions necessary for genetic
equilibrium to occur?
a. no gene shuffling
c. no random mating
b. no gene mutations
d. genetic drift
25. The Grant’s found that different beak sizes among Galapagos finches can
mean the difference between life and death during:
a. drought season
c. severe thunderstorms
b. rainy, wet season
d. breeding season
MATCHING
Match the appropriate term (each represented by a letter) to the definition that
most closely relates to the term. There are more terms than definitions, so all
terms will not be used.
a. natural selection
b. evolution
c. mutation
d. speciation
e. gene shuffling
f .genetic equilibrium
g. founder effect
h. isolating mechanism
i. gene pool
j. ecological competition
26. ____ allele frequencies change as a result of the migration of a small
subgroup of a population
27. ____total diversity of alleles present in a species population
28. ____ something that results in two populations becoming reproductively
separated from each other that can lead to the formation of new
species
29. ____ evolutionary process that results in the formation of a new species
30. ____ process by which nature selects individuals for survival in a particular
environment at a particular time
31. ____ any change in the relative frequency of alleles in a population over
time
32. ____ any change in the sequence of an organism’s DNA
33. ____ allele frequencies in a population remain constant unless one or more
factors cause those frequencies to change
SHORT ANSWER Answer each question using at least complete sentences.
Use the back of this page if you need more room.
1. Natural Selection has often been described as ‘Survival of the Fittest’. Does
this necessarily mean that the stronger, larger or faster an organism is, the
better chances it has of surviving? Demonstrate in your own words, and
provide an example that supports your explanation.
2. Does natural selection act on the individual, the population, or the species?
Explain.
3. What could possibly result from a population that does NOT evolve at all,
but maintains a constant genetic equilibrium?
4. Based on what we have learned about the study of Evolution, present a
reasonable argument with at least 3 supporting statements that evolution is
either THEORY or FACT.
5.Describe how the process of gene shuffling contributes to heritable variation.