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.
The mechanisms of reproductive isolation or hybridization barriers are a collection of mechanisms, behaviors and physiological processes that prevent the members of two different species that cross or mate from producing offspring, or which ensure that any offspring that may be produced are sterile.ny of the factors that prevent potentially fertile individuals from meeting will reproductively isolate the members of distinct species. The types of barriers that can cause this isolation include: different habitats, physical barriers, and a difference in the time of sexual maturity or flowering.