Which description of reinforcement is correct?
Reinforcement is the loss of genetic differences between two populations due to gene flow.
Reinforcement is natural selection against interbreeding and production of hybrid offspring.
Reinforcement is the genetic divergence of populations in different environments.
Reinforcement leads to development of a hybrid zone.
answer
Reinforcement is natural selection against interbreeding and production of hybrid offspring
Correct. In this way not only can natural selection operate differently on the two populations, but individuals produced as a result of genetic mixing are eliminated.
question
How does an apple fly's attraction to a particular type of fruit promote genetic divergence?
On apple trees, they are much more likely to encounter hawthorn flies than other apple flies.
The scent allows female flies to produce more offspring.
On apple trees, they are much more likely to encounter other apple flies than hawthorn flies.
It makes no difference in promoting genetic divergence.
answer
On apple trees, they are much more likely to encounter other apple flies than hawthorn flies.
Correct. Because of the fruit preferences of the two populations, little or no interbreeding occurs between apple flies and hawthorn flies, which reduces gene flow between them.
question
What distinguishes a biological species?
It represents a distinct twig in a phylogeny of populations.
It has distinctive characteristics, such as size, shape, or coloration.
It is reproductively isolated from other species.
It is a fossil from a distinct time in Earth history.
answer
It is reproductively isolated from other species.
question
How did the sunflower species Helianthus anomalus originate?
autopolyploidy
disruptive selection
allopolyploidy
hybridization
answer
hybridization
Correct. Riesenberg, et al. concluded that H. anomalus was formed as a hybrid between two other Helianthus species.
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While H. anomalus is the product of two species, it is not due to mixing two sets of chromosomes from each species.
question
Which is the first step in allopatric speciation?
differential natural selection in different environments
genetic divergence due to mutation
loss of genetic variation due to genetic drift
physical isolation of two populations
answer
physical isolation of two populations
question
Which species concept would be most useful to a team of biologists conducting a biodiversity survey?
the biological species concept
the phylogenetic species concept
All species concepts would be equally useful.
the morphospecies concept
answer
the morphospecies concept
Correct. The most common method for distinguishing species is on the basis of their appearance.
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phylo: Incorrect. This method can use appearance, but it requires analysis of a group of taxa that cannot be done in the field, and often it involves DNA analysis
bio: incorrect. Using this concept requires studying whether populations are reproductively isolated, a difficult job.
question
True or False? Gene flow increases the DIVERGENCE of populations.
answer
false
question
Which statement is correct?
A monophyletic group may include an ancestral population and some, but not all, of its descendants.
A monophyletic group consists of all of the descendants of an ancestral population.
A monophyletic group is a theoretical idea that does not exist in the real world.
A monophyletic group consists of an ancestral population, all of its descendants, and only those descendants.
answer
A monophyletic group consists of an ancestral population, all of its descendants, and only those descendants.
Correct. This is the definition of monophyly.
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It must also include the ancestor.
