Chapter 14: The Origin of Species
# 152826 Cust: Pearson Au: Reece Pg. No. 94
Title: Active Reading Guide for Campbell Biology: Concepts & Connections, 8e
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7. Which of the following represents a post-zygotic barrier?
a. Temporal
b. Habitat
c. Reduced hybrid viability
d. Gametic
8. Two different species of fruit flies mate at different times of the day. One breeds in the morn-
ing and one breeds in the afternoon. What type of reproductive barrier is this?
Big idea: Mechanisms of speciation
Answer the following questions as you read modules 14.4–14.11:
1. A geographic barrier to ____________ can give rise to ____________ speciation.
2. Isle Royale National Park consists of a series of islands located in Lake Superior. Initially,
there were no wolves on any of the islands since they were in the middle of Lake Superior.
However, in 1949, an unusually long and cold winter produced an ice bridge between Canada
and the islands of the National Park. During this winter, a pair of wolves used the ice bridge
to travel inadvertently to Isle Royale. Today there continues to be a wolf population on the
main island descended from that original pair. Has allopatric speciation occurred yet? If not,
could it?
3. True or false: Geographic isolation always leads to speciation. If false, make it a correct
statement.
4. Refer to Figure 14.5 on page 283 of your textbook. Assume that the initial growth medium
was different from both the starch and the maltose. Would the flies in either group, after the
40th generation, be able to reproduce with the flies from the original medium?
This is an example of a temporal prezygotic barrier.
Probably not because not enough time has passed. In theory, it could as long as enough time passes
to allow the wolves on Isle Royale to be subjected to the selective pressures specific to Isle Royale.
False, because some organisms have the ability to spread their seed or move across geographic
barriers, which renders the barriers ineffective.
It is expected that the starch flies and the maltose flies would have the same difficulty mating
with the flies from some other hypothetical medium.
reproduction allopatric
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