As genes pass from parents to offspring, DNA is faithfully copied and passed on but because of diploidy, exact parental genotypes are not always observable phenotypically. Recessive phenotypes can "skip" a generation, and a parent can produce offspring with both parental and non-parental phenotypes. This both helps preserve well adapted phenotypes but also allows new or rare ones to emerge for natural selection to favor under changed circumstances. All of this enhances the variation discussed in Ch. 13 in the discussion of meiosis.
Work Step by Step
This question asks you to review earlier material on meiosis and on evolutionary genetics and to imagine how the phenomena explained in this chapter can both increase diversity and maintain well-adapted parental phenotypes.