Suppose that the natural ranges of horses and donkeys were to overlap.Which statement best describes what is likely to happen to the populations over time?
A) The hybrid offspring (mules) would become widespread and mate with members of both populations.
B) The hybrid offspring would mate with other hybrid offspring to produce viable offspring.
C) The hybrid offspring would be less reproductively fit and reinforcement would strengthen postzygotic barriers.
D) Eventually all members of both populations would be hybrids.
E) The hybrid offspring would be less reproductively fit and reinforcement would strengthen prezygotic barriers.

Question

Suppose that the natural ranges of horses and donkeys were to overlap.Which statement best describes what is likely to happen to the populations over time?
A) The hybrid offspring (mules) would become widespread and mate with members of both populations. 
B) The hybrid offspring would mate with other hybrid offspring to produce viable offspring.
C) The hybrid offspring would be less reproductively fit and reinforcement would strengthen postzygotic barriers.
D) Eventually all members of both populations would be hybrids.
E) The hybrid offspring would be less reproductively fit and reinforcement would strengthen prezygotic barriers.

Quizplus · Accepted Answer

Hybrid offspring, such as mules (resulting from horse and donkey mating), are typically less reproductively fit because they are usually sterile. This sterility means they cannot contribute genetically to future generations, which does not support the spread or sustainability of hybrid populations. Over time, natural selection would favor mechanisms that prevent the less fit hybrid offspring from being produced in the first place. This leads to reinforcement, which strengthens prezygotic barriers (mechanisms that prevent different species from mating) to avoid the production of unfit hybrid offspring.

Suppose That the Natural Ranges of Horses and Donkeys Were