A certain species of salamander was split into two populations by a wide, dry valley, and the populations?
and the populations began to diverge from each other. After a period of time, some members of the two populations began to interbreed in a hybrid zone at the southern end of the valley. Only weak reproductive barriers existed by this time, so the two populations could freely interbreed and re-establish gene flow. This outcome in a hybrid zone is known as . 1) speciation 2) reinforcement 3) fusion 4) punctuated equilibrium 5) stability