Download Unit 6 Exam Review Answers

Unit 6 Exam Review
Supplemental Instruction
Iowa State University
Leader:
Course:
Instructor:
Date:
Chelsey
BIO 211 (3)
Colbert
Wednesday 11/30/11
1. In Darwin’s view of descent with modification
a. An organism’s traits only affect its own survival
b. Natural selection can improve the match between an organism and its
environment
c. Individuals can evolve
d. Environmental changes have no effect on the organisms living in that
environment
2. In the case of the Rhagoletis flies, sympatric speciation has been shown to be driven by
__________
a. Habitat differentiation
b. Mechanical isolation
c. Sexual selection
d. Post-zygotic barriers
3. Which of the following organisms are most likely to be subject to allopatric speciation?
a. Whale populations of the same species located on opposite sides of the Atlantic
Ocean
b. Pine trees in Alaska and pine trees on the island of Madagascar
c. Mountain lions in the canyons of Wyoming and in the canyons of Utah
d. Fruit flies on bananas and fruit flies on oranges
4. The biological species concept emphasizes __________
a. Molecular differences ecological niches
b. The evolution of reproductive isolation
c. Morphological and structural features
d. Common ancestry
5. Which of the following is an example of a postzygotic reproductive barrier?
a. One species of frog mates in April, but another mates in May
b. Two fruit flies of different species produce sterile offspring
c. The sperm of a marine worm can only penetrate eggs of the same species
d. One species of flower grows in forested areas, another in meadows
6. Three species of frogs all mate in the same ponds, but they pair off correctly because they
have different calls. This is an example of a _____ barrier, called _____.
a. Prezygotic barrier, behavioral isolation
b. Postzygotic; hybrid breakdown
c. Prezygotic; temporal isolation
d. Postzytotic, mechanical isolation
7. Which of the following conditions is necessary for speciation to occur?
a. Reproductive isolation
b. Sympatric speciation
c. Adaptive radiation
d. Mass extinction
8. A population of mice is preyed on by eagles. The smaller mice can escape into burrows,
the larger mice can fight off the eagles. After several generations, the mice tend to be
very large or very small. What process is responsible for this outcome?
a. Stabilizing selection
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b. Directional selection
c. Disruptive selection
d. Balancing selection
9. In a large population of squirrels, the frequency of the recessive allele is initially 0.2.
What is the frequency of the dominant allele? Assume that there are two alleles of this
gene.
a. 10%
b. 20%
c. 50%
d. 80%
10. A population of 15 birds inhabits a fairly new island. Ten of the birds are dark brown
and five are light brown. By chance, two of the dark brown birds and three of the light
brown birds die before producing offspring. All of the birds in the next generation are
dark brown. This can be attributed to _____.
a. Gene flow
b. Genetic drift
c. Natural selection
d. Disruptive selection
11. Which of the following is the best example of gene flow?
a. A small population of humans colonizes a new island
b. A small population of mice from England get onto an airplane bound for Canada
where they join the a population of their same species
c. Genes are shuffled by the crossing over of chromosomes during meiosis
d. An earthquake results in the formation of a canyon, splitting a population of toads
apart
e. Wind blows pollen from one plants to another and cross-fertilization occurs
12. An earthquake hits a small island. All but a small group of closely related lizards are
eliminated, and the survivors spread out over the island. This is an instance of _____.
a. Founder effect
b. Bottleneck effect
c. Gene flow
d. Mutation
13. In a certain group of African people, 10% are born with sickle-cell disease (homozygous
recessive). If this group is in Hardy-Weinberg equilibrium, what percentage of the group
has the selective advantage of being more resistant to malaria (heterozygous) than those
individuals who are homozygous for normal hemoglobin or for sickle-cell disease?
a. 16%
b. 10%
c. 43%
d. 32%
14. How many different fossil species of human ancestors have been found?
a. 1
b. 5
c. 20
d. 50
e. 150
15. In the context of populations, how do we define evolution?
a. A change in the population’s allelic frequencies over generations
b. Evolution is the tendency for some individuals in a population to leave more
offspring than others
c. Evolution is the way in which sexual reproduction can rapidly spread
advantageous traits throughout a population
d. Always caused by natural selection
16. The smallest unit that can evolve is a(n) __________.
a. Species
b. Genotype
c. Individual
d. Population
17. In a population in Hardy-Weinberg equilibrium, 36% of the individuals in a population
show the recessive trait of a certain characteristic. In this situation, what is the frequency
of the dominant allele?
a. 0.64
b. 0.60
c. 0.40
d. 0.80
18. When they were first sold, aerosol insecticides were highly effective in killing flies and
mosquitoes. Now, several decades later, a much smaller proportion of these insects die
when sprayed. The reason fewer insects die when they are sprayed is that _____.
a. Mosquitoes that survive spraying develop an immunity to the insecticide
b. Many mosquitoes today are descendants of mosquitoes with insecticide-resistant
characteristics
c. Mosquitoes are deliberately adapting themselves to this man-made change in the
environment
d. The original spraying has caused a permanent mutation, giving the insects genetic
resistance to the spray
19. How long ago did humans reach the western hemisphere?
a. 170,000 years ago
b. 100,000 years ago
c. 60,000 years ago
d. 20,000 years ago
e. 10,000 years ago
20. How many years worth do we have recorded history of?
a. 250
b. 500
c. 5,000
d. 20,000
21. Different breeds of dog ____ interbreed because _____.
a. Can, they’re all members of the same subphylum
b. Cannot, breeds are members of different subphyla
c. Can, they’re all members of the same species
d. Cannot, breeds are members of different subspecies
e. Can, they’re all members of the same species but different subspecies