Chapter 6 Quiz

Quiz Content

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. Which example does not include a case of phenotypic variance?

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. Refer to the figure showing the fitness function for combinations of two traits in the northwestern garter snake (Thamnophis ordinoides), based on survival in the field.



If we ignore the long-term effects of genetic drift, what effect will correlational selection have on coloration and escape behavior by this garter snake population?

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. Which of the following would likely cause the greatest mean rates of change to morphological characters in a large population with a constant mutation rate?

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. Imagine a population of Galápagos finches that vary for bill size. If the population mean is near the optimum size for eating the seeds found on the island, what would we expect to occur if their main seed resource goes extinct, and another plant with much larger seeds replaces it?

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. Refer to the graph showing the pattern of newborn human survival as a function of birthweight.



Based on the graph and what you know about modes of selection, estimate the selection gradient, β, on birthweight.

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. What happens to the heritability of a trait as the most fit allele in the population approaches fixation?

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. The change in the average trait value of a population under selection is equal to the heritability multiplied by the selection differential. The selection differential is the

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. Phenotypic variance that is not due to genetic variance can be attributed to

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. Response of a quantitative character to selection will be greatest when heritability is _______ and selection is _______.

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. Which condition might interfere with a breeder's attempt to predict the change in a trait over many generations based on their knowledge of the trait's heritability?

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. The phenotypic effect of synergistic interactions among loci is referred to as

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. Many people think long-term evolution of a species must follow the rule "adapt or die." Which of the following will not help organisms overcome an environmental change that threatens extinction?

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. Stabilizing selection is often observed in nature because of

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. What is meant by the statement "Evolution may proceed along 'genetic lines of least resistance'"?

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. Anthropogenic climate change is taking place at such a fast rate that many species will fail to adapt quickly enough to avoid extinction. Which of the following may constrain evolution in response to human-induced climate change?

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. Genetic correlations can have two causes: _______ and _______.

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. In correlated selection, selection favors some combination of character states over others, usually because the characters

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. Which pair of traits are least likely to be genetically correlated?

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. When the environment affects the phenotypes of all the genotypes in a population and the reaction norms of the genotypes are parallel,

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. QTL mapping is a method for detecting loci that contribute to quantitative trait variation. This method relies on the association between phenotypic differences and molecular markers. A QTL typically refers to a

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