Biology 138
Name _____________________
“Old Things Into New” Study Guide
1.
The topic of this chapter of the book Evolution: The Story of Life on Earth by Jay Hosler is
speciation. In your own words, define “speciation.”
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2.
The evolutionary biologist Ernst Mayr is credited with developing the Biological Species
Concept. After reading the strict definition developed by Mayr, as well as the description
provided by the author, develop your own explanation of the Biological Species Concept and
write it here.
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3.
Think of at least two types of organisms with which the Biological Species Concept would not be
able to be used, and explain why it could not be used for them in the space below.
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4.
How can different species of lacewings distinguish themselves from one another if they look so
similar?
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5.
What factor is the single biggest key to speciation? Why do you think this is so crucial?
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6.
Does natural selection act directly upon phenotype or genotype? What is the connection
between phenotype and genotype?
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7.
Why can’t natural selection give “Orbi’s” wings? Be sure to include the term gene pool in your
answer.
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8.
How might one “Orbi” develop hair tufts? What force might naturally select for the hair tuft trait
to become more common in the population?
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9.
What is the easiest way for two populations to become separated? Define this term in your own
words.
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10. What key process is interrupted when a physical barrier arises? Define this process in your own
words.
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11. Describe the difference in environments on the Western and Eastern side of the mountain range
that separates the two “Orbi” populations.
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12. Identify 2 morphological adaptations and one behavioral adaptation in each “Orbi” population.
Western Orbi: _______________________________________________________________
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Eastern Orbi: ________________________________________________________________
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13. Why is it that the separation of populations is so important? What happens when an Eastern
and Western Orbi meet?
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14. Define the term “zygote.”
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15. When sperm and egg are prevented from fusing together, these barriers to reproduction that
separate species are referred to as prezygotic isolating mechanisms. For each of the
organisms below, identify the type of prezygotic isolating mechanism that separates the different
populations into separate species, and give a brief description of the mechanism.
a. Gryllus pennsylvanicus and Gryllus veletis: ______________________________________
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b. Marmosets of the Amazon Rainforest ___________________________________________
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c. Bowerbirds ________________________________________________________________
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16. Define the term “sexual selection” in your own words.
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17. If natural selection is about the “survival of the fittest,” then why don’t both male and female
Indonesian Babirusas have large canines growing out of the top of their skulls? In other words,
how could a trait make one gender of a species more fit, but not do the same thing for the other
gender?
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18. Give two reasons why a female bowerbird should care if the male can sing and dance and build
a pretty nest.
1.
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2.
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19. How can geographic isolation and sexual selection work together to drive speciation?
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20. When gene flow is not allowed to occur between two species because of problems that arise in
the hybrid organism that is formed after the fusing of sperm and egg, these are referred to as
postzygotic isolating mechanisms. What are the two types of postzygotic isolating
mechanisms that act to prevent two different species from producing fertile, viable offspring?
1. _________________________________________________________________________
2. _________________________________________________________________________
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21. Give an example from nature of one of the two types of postzygotic isolating mechanisms that
you identified in question number 20. Explain the issue with the hybrid offspring that is produced
in your example.
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22. Define speciation and list the five steps required for speciation to occur:
Speciation: __________________________________________________________________
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1.
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2.
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3.
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4.
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5.
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