Chapter 24, Problem 13TYK

This chapter introduced several research studies that illustrate various aspects of speciation. Which of the following is not an accurate description of a conclusion based on one of these studies?

1. a. Two closely related species of monkey flowers have different pollinators (bumblebees and hummingbirds). Transferring an allele for flower color between the two species resulted in both types of pollinators visiting flowers with the transferred flower allele. Thus, this reproductive barrier based on pollinator choice may have been influenced by a change in a single gene locus.
2. b. The apparent stability of the hybrid zone between two species of Bombina toads may relate to the narrow width of the zone. Even though hybrid toads have increased rates of embryonic mortality and a variety of morphological abnormalities, members of both parent species continue to migrate into the zone, leading to the production of hybrids.
3. c. Populations of mosquitofish inhabit ponds in the Bahamas. In ponds that contain predatory fishes, natural selection has favored a body shape that facilitates rapid bursts of speed. In mate choice experiments, female mosquitofish choose males with body shapes similar to their own. The reproductive isolation between populations is forming as a by-product of natural selection for predator avoidance.
4. d. In the many species of cichlids found in Lake Victoria, the reproductive barriers between species as a result of female mate choice based on male coloration appear to be breaking down because the introduced Nile perch is a strong predator of cichlids.