| DQ 22.1 |
Why do we need to classify organisms into species?
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| DQ 22.2 |
All living organisms trace back to a common ancestor via a continuous line of descent. Why, then, do organisms cluster into species despite this continuity of evolution?
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| DQ 22.3 |
The
biological species is the most widely used definition of a species. What are its disadvantages and advantages?
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| DQ 22.4 |
A
genealogical species is defined as a group of individuals for whom the genealogies at all loci in the genome are
reciprocally monophyletic. In other words, for each locus, all genes within the group must be more closely related to each other than they are to any organisms outside the group. Is this a practical definition for a species? (For more background, see Web Notes.)
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| DQ 22.5 |
Diverse ecological resources can be exploited by different genotypes within a species and by different species. What factors influence whether ecological diversification occurs within, as opposed to between, species?
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| DQ 22.6 |
What factors determine the number of species that are found in any one area?
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| DQ 22.7 |
What is the distinction between
prezygotic and
postzygotic isolation? Why is it important?
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| DQ 22.8 |
What factors determine the rate at which diverging populations become reproductively isolated?
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| DQ 22.9 |
Explain how divergence can occur despite gene flow.
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| DQ 22.10 |
What evidence would be needed to show that a species originated in sympatry?
NOTE 22A
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| DQ 22.11 |
Is the evolution of host races in the fly Rhagoletis pomonella sympatric, parapatric, or allopatric?
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