Isolating Mechanisms — Definition & Examples

Pre-zygotic: The zygote created by the two species mating is infertile, and therefore isolation occurred at the pre-zygotic level

Pre-zygotic: all isolation occurs before the creation of a zygote

Post-zygotic: because the species can still mate, but the offspring is not fertile and therefore the isolation occurs after the creation of the zygote

Post-zygotic: all isolation occurs after the creation of a zygote