Final answer:
If the fitness of a hybrid is greater than that of its parental species, there may be maintenance of hybrids leading to a single species, reinforcement of reproductive isolation, or stability with no significant evolutionary change.
Step-by-step explanation:
If the fitness of a hybrid is higher than the fitness of the parental species, several potential outcomes are possible:
- Maintenance of hybrids: Reproduction would likely continue between both species and the hybrids, possibly leading to homogenization into a single species that encompasses the genetic traits of both original species.
- If two closely related species continue to produce hybrids that are less fit than the parent species, this can lead to reinforcement of reproductive isolation, as less fit hybrids have a lower reproductive success rate, which reinforces the speciation process between the two species.
- Alternatively, the two species could remain separate but continue to interact and produce some hybrid individuals, without significant changes to each species. This situation is called stability because no net evolution in either species is occurring.
Which reproductive combination produces hybrids? It generally occurs when members of closely related species reproduce in a hybrid zone.