Multiple Choice
A female fly, full of fertilised eggs, is swept by high winds to an island far out to sea. She is the first fly to arrive on this island and the only fly to arrive in this way. Thousands of years later, her numerous offspring occupy the island, but none of them resembles her. There are, instead, several species, each of which eats only a certain type of food. None of the species can fly and their balancing organs (halteres) are now used in courtship displays. The male members of each species bear modified halteres that are unique in appearance to their species. Females bear vestigial halteres. The ranges of all of the daughter species overlap.
Fly species W, found in a certain part of the island, produces fertile offspring with species Y. Species W does not produce fertile offspring with species X or Z. If no other species can hybridise, then which of the following statements about species W and Y are true?
I. Species W and Y have genomes that are still similar enough for successful meiosis to occur in hybrid flies.
II. Species W and Y have more genetic similarity with each other than either did with the other two species.
III. Species W and Y may fuse into a single species if their hybrids remain fertile over the course of many generations.
A) Only I is correct.
B) Only II is correct.
C) Only III is correct.
D) I, II, and III are correct.
Correct Answer:

Verified
Correct Answer:
Verified
Q3: A narrow hybrid zone separates the toad
Q19: Reinforcement is most likely to occur when
Q27: Which of the following statements describes mechanical
Q32: The largest unit within which gene flow
Q37: Which postzygotic barriers prevent formation of hybrids
Q46: The largest unit within which gene flow
Q50: The common edible frog of Europe is
Q63: Many songbirds breed in North America in
Q64: Which of these animals could overcome the
Q65: The peppered moth provides a well-known example