Navy blue. For other uses, see Navy blue (disambiguation). Navy blue is a very dark shade of the color blue. French sailor in dark blue uniform. Navy blue got its name from the dark blue (contrasted with white) worn by officers in the British Royal Navy since 1748 and subsequently adopted by other navies around the world.
Hybrid sterility is what results when individuals from two. different species are able to mate but their offspring is infertile, meaning that their. offspring are not able to reproduce. Because this occurs after the formation of the. zygote, this is a postzygotic isolating mechanism, not a prezygotic mechanism.
In summary, a postzygotic reproductive barrier is a mechanism that reduces the viability or reproductive capacity of hybrid offspring. Hybrid zygote abnormality is a type of postzygotic barrier in which hybrid zygotes fail to mature normally.Hybrid infertility is a type of postzygotic barrier in which hybrids are incapable of producing offspring.Low hybrid viability is a type of postzygotic barrier in which the viability of hybrid offspring is lower than offspring in either population.ostzygotic reproductive barriers occur after the zygote has formed, meaning they either reduce the viability (which basically means the ability to avoid dying) or the reproductive capacity of the hybrid offspring.