Reproductive Barriers: Antelopes and Bassett Hounds, Essay Example

Prezygotic reproductive barriers are important as they do not waste gametes and also the energy for gestation is not wasted and the subsequent development of the offspring. There are certain barriers which interfere with the fertilization. Prezygotic barriers interfere with the fertilization before the union of gametes and postzygotic barriers act after the unification of the gametes. The prezygotic barriers include the reproductive isolating mechanisms where in the fertilization between members of the different species is prevented. Temporal isolation and habitat isolation are the prezygotic barriers. In temporal isolation two species reproduce at different times of the day, season or year. Habitat isolation involves two potential species living in two different habitats whose ranges overlap and so they do not encounter each other. Behavioral isolation, mechanical isolation and gamete isolation are also considered as prezygotic barriers. Behavioral isolation involves differentiation with the characteristic courtship behaviors. Mechanical isolation occurs when the genital organs are incompatible in different species. Gametic isolation prevents fertilization as the egg and sperm of different species are incompatible (Eldra Solomon, Linda Berg, Diana W. Martin, 2002).

The postzygotic barriers include hybrid inviability, hybrid sterility and hybrid breakdown. Hybrid inviability is reason for the embryonic death. The hybrid offspring of two species do not mature and dies at the embryonic stage. At instances where the hybrid offspring matures normally, the reproduction of these hybrids is not normal due to hybrid sterility. Hybrid breakdown is the reason for the unsuccessful reproduction of the hybrid offspring or the second generation hybrids (Eldra Solomon, Linda Berg, Diana W. Martin, 2002).

References:

Eldra Solomon, Linda Berg, Diana W. Martin, 2002, What prevents closely related species from interbreeding, Biology, [Online], Available at: http://163.16.28.248/bio/activelearner/19/ch19c1.html, Accessed on 01.04.2013.