Evolution Chapter 15 Discussion Questions
DQ 15.1 |
If the “tape of life” were played again, how different would the outcome be? In other words, if life began again, and evolved through the same processes, how similar would the outcome be to our actual world? NOTE 15A
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DQ 15.2 |
Explain the various sources of randomness in evolution.
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DQ 15.3 |
A basic evolutionary principle is that mutations are random with respect to adaptation (pp. 343–347, 414). Suppose, however, that this were not the case and that an organism’s environment could alter the kinds of mutations that it transmits to its offspring. Can you imagine a biological mechanism for this kind of “Lamarckian” inheritance? Would such a mechanism be favored by natural selection?
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DQ 15.4 |
Read Chapter 10 of Dawkins’ (1982) The extended phenotype, titled “An agony in five fits.” What definitions of fitness does Dawkins review? What are the difficulties with each? (Definitions 4 and 5 are discussed in Chapter 21; you might leave these aside and return to them after reading that chapter.)
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DQ 15.5 |
In mammals, males often have greater variance in reproductive success than females, as a result of sexual selection. How will this alter the effective population size of genes on the autosomes, the X chromosome, the Y chromosome, and the mitochondrial genome? What other factors may influence the genetic diversity on these different parts of the genome?
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DQ 15.6 |
A $10 million prize has been offered for the first team to sequence 100 human genomes in ten days (http://www.xprize.org/xprizes/genomics_x_prize.html). Given complete sequence information, how would you estimate the coefficient of kinship between two individuals (p. 421)? How distant a relationship would be detectable? What might be the implications of being able to detect relationships in this way?
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DQ 15.7 |
Explain how the shape of a genealogy is influenced by the history of a population.
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DQ 15.8 |
What are the key observations that support the neutral theory?
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DQ 15.9 |
If we trace our pedigree back for more than about 40 generations, then we all share the same set of great-great-... grandparents. What are the implications of this shared ancestry?
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DQ 15.10 |
The age of an allele can be estimated from the frequencies of linked markers (Fig. 15.18). What does knowing the age of an allele tell us about it?
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References
Dawkins R. 1982. The extended phenotype. Oxford University Press, Oxford.
Dawkins R. 1997. Human chauvinism. Evolution 51: 1015–1020.
Gould S.J. 1989. Wonderful life: The Burgess Shale and the nature of history. W.W. Norton, New York.
Gould S.J. 1997. Self-help for a hedgehog stuck on a mole-hill. Evolution 51: 1020–1023.
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