If one species reproduces in the spring, while the other reproduces in the fall, the two species aren t able to breed. Behavioral isolation is another isolating mechanism. This mechanism operates through courtship behavioral patterns. If one species displays a certain courtship pattern, it won t be recognized by those of the other species. This is the mechanism which separates wolfs from dogs, their courtship patterns are different in the wild.
Mechanical isolation deals with the actual mechanics of the reproductive organs.
Mechanical isolation acts a prezygotic barrier by preventing sexual intercourse between two different species. This is to say that artificial selection can overcome the above isolation mechanisms. However, gametic isolation, and postzygotic barriers can t be overcome by any known means. Gametic isolation is where the gametes of the two species are chemically incompatible, thus preventing fertilization. Hybrid inviability, the first of three postzygotic barriers, causes an inviable offspring to be produced through hybridization.