A young man with phenylketonuria, who was successfully treated following diagnosis on newborn screening, is planning to start a family with his healthy, unaffected, and unrelated partner, who has no family history of phenylketonuria . Phenylketonuria shows autosomal recessive inheritance with an incidence of 1 in 10 000. Assume that the population is in Hardy-Weinberg equilibrium. Which of the following is correct?

#Question id: 4645

#Unit 9. Evolution & Diversity of Life Forms

The treeʹs horizontal axis is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labeled branch points on the tree (V—Z) represent various common ancestors. Letʹs say that only since 50,000 years ago has there been enough variation between the lineages depicted here to separate them into distinct species, and only the tips of the lineages on this tree represent distinct species.

Which of the five common ancestors, labeled V—Z, has given rise to the greatest number of species, both extant and extinct?

#Question id: 4646

#Unit 9. Evolution & Diversity of Life Forms

The treeʹs horizontal axis is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labeled branch points on the tree (V—Z) represent various common ancestors. Letʹs say that only since 50,000 years ago has there been enough variation between the lineages depicted here to separate them into distinct species, and only the tips of the lineages on this tree represent distinct species.

Which of the five common ancestors, labeled V—Z, has been least successful in terms of the percent of its derived species that are extant?

#Question id: 4647

#Unit 9. Evolution & Diversity of Life Forms

The treeʹs horizontal axis is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labeled branch points on the tree (V—Z) represent various common ancestors. Letʹs say that only since 50,000 years ago has there been enough variation between the lineages depicted here to separate them into distinct species, and only the tips of the lineages on this tree represent distinct species. Which of the five common ancestors, labeled V—Z, has been most successful in terms of the percent of its derived species that are extant?

#Question id: 4648

#Unit 9. Evolution & Diversity of Life Forms

In a hypothetical environment, fishes called pike-cichlids are visual predators of algae-eating fish (i.e., they locate their prey by sight). If a population of algae-eaters experiences predation pressure from pike-cichlids, which of the following should least likely be observed in the algae-eater population over the course of many generations?

#Question id: 4649

#Unit 9. Evolution & Diversity of Life Forms

Which statement best describes the evolution of pesticide resistance in a population of insects?

#Question id: 4650

#Unit 9. Evolution & Diversity of Life Forms

DDT was once considered a ʺsilver bulletʺ that would permanently eradicate insect pests. Today, instead, DDT is largely useless against many insects. Which of these would have been required for this pest eradication effort to be successful in the long run?