I believe the answer you are seeking is feedback loop
Answer:the species could be seperated by many differnt barreirs like a storm that destroys a habitat and the species is split up but this does not mean that a new species would develop.
Explanation:
This is because the only reason new speices would develop is if when they get seperated the species move to a new environment forcing them to adapt.
Insects, frogs, rodents. Little stuff like that.
The answer is Available habitats