Final answer:
Hybrids are the offspring resulting from interspecific mating. These can become more fit than their parents, creating a new lineage or species through hybridization. The outcome of such matings can vary, potentially leading to genetic extinction or reinforcement of species barriers.
Step-by-step explanation:
Offspring that result from an interspecific mating are typically known as hybrids. In certain cases, if these hybrids are more fit than their parents, they may continue to reproduce, potentially leading to a situation where all organisms involved become part of one species, illustrating hybridization. An example of this phenomenon happens when a normal gamete from one species fuses with a polyploid gamete from another, creating an allopolyploid organism. This organism, often tetraploid or 4n, can usually only reproduce with other similar tetraploid organisms, creating a distinct lineage separate from the ancestral species.
In contrast, when species mated extensively and the hybrid offspring survive and reproduce less well than those from intra-species matings, this can lead to reinforcement of the separate species. Also, hybridization can result in genetic extinction if one species becomes overwhelmed by another through extensive interbreeding, such is the case with the Texas fish Gambusia amistadensis or the New Zealand grey duck.
Moreover, after speciation has occurred, closely related species may produce offspring in a region called the hybrid zone. Depending on the reproductive barriers and the relative fitness of the hybrids, outcomes like reinforcement, fusion, or stability may arise, impacting the continued existence of these species separately or as a unified gene pool.