Parthenogenetic development of unfertilized eggs as a regular procedure in the production of male ants and bees and Artificial stimulation of sea urchin eggs induces cleavage. Although the egg is a sex cell, the development of unfertilized eggs is an asexual process.Among sponges and hydra, budding is a common occurrence. This involves an outgrowth of a portion of the parent’s body to produce a new individual. Occasionally, the new growth will remain attached to the parent stock, but usually the bud breaks away to produce an individual organism.
In the phylum, Platyhelminthes, a process called fragmentation occurs in which some of these flatworms spontaneously separate into separate lengths. Each of the fragments produces a new flatworm.
Related to fragmentation is regeneration, or the restoration of lost parts. Seemingly, this is a mechanism for compensating for the accidental removal of organs or extended structures. However, among the echinoderms (starfish, brittle stars, etc.), the removal of an arm and part of the central disk leads to the formation of a new organism from that arm, so that the process may be considered both fragmentation and regeneration.
Asexual reproduction is a simple procedure for producing progeny, but it tends to minimize the variation which is grist for the mill of evolution. It also tends to eliminate the existence of parents, except in the instance of budding. In almost all animal organisms, asexual reproduction is only a supplement to sexual reproduction.