[Campbell Biology P.569] The text states that the Bombina hybrid zone remains stable despite... | Practice Question

The text states that the Bombina hybrid zone remains stable despite hybrids being "strongly selected against." What is the primary explanation provided for the continued production of hybrids in this zone?

  • A: Hybrids in the Bombina zone have unexpectedly high fitness in specific microhabitats.
  • B: Parent species continue to migrate into the narrow hybrid zone from outside populations, replenishing hybrid formation.
  • C: The Bombina hybrid zone is exceptionally wide, allowing for greater gene flow and hybrid survival.
  • D: Natural selection favors the hybrid individuals over purebred individuals within the zone.

Explanation

The text states: 'One explanation relates to the narrowness of the Bombina hybrid zone...Evidence suggests that members of both parent species migrate into the zone from the parent populations located outside the zone, thus leading to the continued production of hybrids.'