Final answer:
Gametic isolation is a premating reproductive isolation mechanism that occurs before zygote formation. It is a type of prezygotic barrier that prevents fertilization from taking place.
Step-by-step explanation:
Gametic isolation is a premating reproductive isolation mechanism that occurs before zygote formation. It is a type of prezygotic barrier that prevents fertilization from taking place. Gametic isolation occurs when the differences in the gamete cells (eggs and sperm) of closely related organisms prevent successful fertilization. Reproductive isolation refers to mechanisms that prevent different species or populations from interbreeding and producing viable offspring. There are two main phases of reproductive isolation: premating and postmating.