Evolution depicts the purpose of an organism as that of reproducing for the existence of genus. Organ systems in animals are responsible for the life of the animal up to the period of genetic conveyance to offspring.  The reproduction phenomenon is classified as sexual and asexual reproduction. Asexual reproduction entails budding, regeneration and parthenogenesis. Budding is evident in cnidarians such as hydra where the progeny develops on the side of the parent making a genetically similar copy. Regeneration is prevalent in earthworms and starfish as they separate and develops separately. Parthenogenesis is evident when eggs cells of animals separate mitotically in an unfertilized state. Sexual reproduction occurs due to the fusion haploid gametes originating from two parents