Postzygotic Reproductive Isolation, Overview
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State
A postzygotic barrier acts after a zygote has already formed, preventing a hybrid offspring from developing, surviving, or reproducing successfully.
Show
A hybrid embryo that fails to develop normally past an early stage is blocked by a postzygotic barrier, not a prezygotic one.
Watch for
Students sometimes misclassify a failed mating attempt as postzygotic failure — it blocks fertilization itself, making it prezygotic instead.