Download Bio112HW3 - Napa Valley College

Bio112 Ecology
Evolution and Ecology
REVIEW QUESTIONS
Multiple Choice
1. Which of the following cannot be an example of evolution?
a. As a consequence of legislation promoting cleaner air, the frequency of black peppered moths in Europe
has decreased in the last half century.
b. After repeated exposure to high temperatures, an individual turtle can tolerate heat more successfully.
c. As a consequence of climate change, robins in the northeastern United States sing earlier in the spring
than they did two decades ago.
d. Due to a genetic bottleneck, the frequency of one allele has increased in a population of the fruit fly
Drosophila subobscura.
2. Tall people generally have tall parents, and short people tend to have short parents. Based on this
observation, we can infer that height is
a. evolving in the human population.
b. due to a single gene.
c. a heritable trait.
d. not a genetically-based trait.
3. Grasshoppers and crickets share many similar characteristics such as general body form, elongated hind
wings (which they use for jumping), and particular wing structures. The simplest hypothesis that would
explain the similarities between these insects is that they resulted from
a. shared ancestry.
b. gene flow.
c. genetic drift.
d. mutation.
4. Which process is the least likely to be the direct cause of appreciable change in allele frequencies over
short periods of time?
a. Mutation
b. Genetic drift in small populations
c. Gene flow
d. Directional selection
5. Which of the following can produce new combinations of alleles in a population?
a. Directional selection
b. Stabilizing selection
c. Genetic drift
d. Recombination
6. After large seeds became more common, the average beak size of the medium ground finch increased in
size over the course of a few years. This change was most likely a case of
a. disruptive selection.
b. directional selection.
c. stabilizing selection.
d. genetic drift.
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Bio112 Ecology
Human Impacts on Evolution
1. Trophy hunting in bighorn sheep has had an inadvertent evolutionary consequence: the sheep have
become _______ and their horns have become _______.
a. larger; larger
b. larger; smaller
c. smaller; larger
d. smaller; smaller
2.‒3. The graphs below show the changes associated with the overall size of bighorn sheep (top), and the
size of their horns (bottom) during the period between 1975 and 2005.
2. According to the graphs, the sheep in 2005 on average weighed approximately _______ than sheep
weighed in 1976.
a. 10 kg less
b. 20 kg less
c. 10 kg more
d. 20 kg more
3. According to the graphs, the sheep in 2005 had horns that were approximately _______ than average
horn lengths found in sheep in 1976.
a. 20 cm shorter
b. 26 cm shorter
c. 30 cm shorter
d. 38 cm longer
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Bio112 Ecology
NATURAL SELECTION
Refer to the diagram below showing four cases of selection on egg number in a population of flour beetles.
The solid blue line represents the frequency of the original population, and the dashed red lines represent
the frequency distributions after eight generations.
1. Which of the following most likely represents a case of disruptive selection?
a. Graph A
b. Graph B
c. Graph C
d. Graph D
2. Which of the following most likely represents a case of stabilizing selection?
a. Graph A
b. Graph B
c. Graph C
d. Graph D
3. Graph B most likely represents a case of
a. stabilizing selection.
b. directional selection.
c. disruptive selection.
d. increased mutation.
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Bio112 Ecology
4. In which case did the variance within the population for egg laying increase the most?
a. A
b. B
c. C
d. D
5. In which process do some individuals have heritable phenotypic traits that give them an advantage in
either survival or reproduction?
a. Directional selection
b. Disruptive selection
c. Genetic drift
d. Both a and b
6. Which process changes allele frequencies by chance alone?
a. Disruptive selection
b. Stabilizing selection
c. Genetic drift
d. Both a and b
7. Which statement about genetic drift is false?
a. It affects allele frequencies the most when populations are small.
b. It can cause slightly deleterious alleles to be fixed in populations.
c. It tends to decrease genetic variation within populations.
d. It tends to decrease genetic differences among different populations.
8. What factor is important in minimizing the impacts of genetic drift?
a. Mutation rate
b. Population size
c. Generation time of the organism
d. None of the above; the effects of genetic drift are constant across all populations.
9. Which pair of evolutionary processes can introduce new alleles into a population?
a. Mutation and recombination
b. Genetic drift and recombination
c. Disruptive selection and gene flow
d. Gene flow and mutation
10. Suppose that several flies of a population that previously fed on blueberries start to feed on
honeysuckle. Due to genetic differences that accumulate as the flies adapt to feeding on honeysuckle, these
“honeysuckle” flies eventually breed earlier than the ancestral flies. This change most likely represents an
early stage of speciation brought about by
a. a geographical barrier.
b. an ecological barrier (specifically temporal isolation).
c. genetic drift.
d. adaptive radiations.
11. As a habitat becomes fragmented, the population sizes of a species in the habitat should _______,
effects of genetic drift should _______, and genetic variation within populations of this species should
_______.
a. increase; increase; increase
b. increase; increase; decrease
c. decrease; increase; decrease
d. decrease; decrease; increase
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Bio112 Ecology
1.–4. Refer the figure below. You are studying a remote island before and after a volcanic eruption. Data at
time 1 was collected one month before the eruption, and data at time 2 was collected one month after the
eruption. All of the species on the island are endemic. The island is 100 km across. Species A and B (the
two snail species) generally only move a distance of 2 m a day. Species C (the bird) often covers 20 km a
day in search of food. After the eruption, the lava flow hardens, and the island is divided by a 20-km strip
of bare rock with few if any resources these animals need to survive.
Figure 1
1.
Would you expect to see a change in patterns of gene flow in species B and C? Why or why not?
2.
Deaths of individuals due to the volcanic eruption could change the frequency of alleles in these
very small island populations. However, you do not have data on the allele frequencies before and
after the eruption for any of these species. Based on your understanding of genetic change, do you
expect that these three species would be affected by genetic drift? Why or why not?
3.
Based on your knowledge of gene flow, genetic drift, and speciation, what do you predict will
happen over the long term to these species? Do you predict that the current species will remain the
same species, or do you think they might split? How would you be able to determine whether a
species had split into two new species?
4.
What is the most likely explanation for what happened to species A as a result of the volcanic
eruption?
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Bio112 Ecology
Figure 2
Textbook Reference: Concept 6.4 Long-term patterns of evolution are shaped by large-scale processes such
as speciation, mass extinction, and adaptive radiation
Bloom’s Category: 5. Evaluating
1. Which species is the oldest? What evidence do you have to support this?
2. Which two species are most closely related? What evidence do you have to support this?
3. Species D is no longer living. When could it have become extinct?
4. When did an adaptive radiation take place?
5. Suppose that species B, C, E, and F all share characteristics that are very different from those of species
D, but there are currently no living species that “fill the gap” between the B/C/E/F group and species D.
Now suppose you could team up with a paleontologist to look for fossils to better understand how B/C/E/F
became so different from species D. What age of rocks would you look for to target your search?
pg. 6