Biology / Unit 8 Bio 1709 short lesson, about 20 seconds
Prezygotic Reproductive Isolation, Overview
Captions available
The idea
A prezygotic barrier prevents fertilization from occurring at all between two populations, blocking reproduction before any zygote can form.
In practice
Two populations whose breeding seasons no longer overlap cannot fertilize each other, a prezygotic barrier operating before any mating attempt succeeds.
Where people slip
A prezygotic barrier acts before fertilization — a postzygotic barrier, covered separately, instead acts after a zygote has already formed.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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