Fragmentation (reproduction)
Fragmentation in multicellular or colonial organisms is a form of asexual reproduction or cloning, where an organism is split into fragments. Each of these fragments develop into mature, fully grown individuals that are clones of the original organism. The organism may develop specific organs or zones to shed or be easily broken off. If the splitting occurs without the prior preparation of the organism, both fragments must be able to regenerate the complete organism for it to function as reproduction. Fragmentation as a method of reproduction is seen in organisms such as filamentous cyanobacteria, molds, lichens, sponges, acoel  flatworms, some annelid worms and sea stars. Fragmentation in various organisms. Molds, yeasts and mushrooms, all of which are part of the Fungi kingdom, produce tiny filaments called hyphae. These hyphae obtain food and nutrients from the body of other organisms to grow and fertilize. Then a piece of hyphae breaks off and grows into a new individual and the cycle continues. Many lichens produce specialized structures that can easily break away and disperse. These structures contain both hyphae of the mycobiont and the algae (phycobiont) (see soredia and isidia). Larger fragments of the thallus may break away when the  lichen dries or due to mechanical disturbances (see the section on reproduction in lichens). Plants. Fragmentation is a very common type of vegetative reproduction in plants. Many trees, shrubs, nonwoody perennials, and ferns form clonal colonies by producing new rooted shoots by rhizomes or stolons, which increases the diameter of the colony. If a rooted shoot becomes detached from the colony, then fragmentation has occurred. There are several other mechanisms of natural fragmentation in plants. People use fragmentation to artificially propagate many plants via division, layering, cuttings, grafting, micropropagation and storage organs, such as bulbs, corms, tubers and rhizomes. Animals . Sponges and coral colonies naturally fragment and reproduce. Many species of annelids and flat worms reproduce by this method. When the splitting occurs due to specific developmental changes, the terms architomy, paratomy and budding are used.In'architomy' the animal splits at a particular point and the two fragments regenerate the missing organs and tissues. The splitting is not preceded by the development of the tissues to be lost. Prior to splitting, the animal may develop furrows at the zone of splitting. The headless fragment must regenerate a complete new head. In 'paratomy', the split occurs perpendicular to the antero-posterior  axis and the split is preceded by the "pregeneration" of the anterior structures in the posterior portion. The two organisms have their body axis aligned i.e. they develop in a head to tail fashion. Budding is similar to paratomy except that the body axes need not be aligned: the new head may grow toward the side or even point backward (e.g. "Convolutriloba retrogemma" an acoel flat worm). Coral. Many types of coral colonies can increase in number by fragmentation occurring naturally or artificially. Reef aquarium enthusiasts fragment corals for various purposes including shape control; sharing with others; regrowth experiments; and  minimizing damage to natural coral reefs. Both hard and soft corals can be fragmented. Genera highly tolerant of fragmentation include "Acropora", "Montipora", "Pocillopora", "Euphyllia", and "Caulastraea" among others. Most sea anemones reproduce through fragmentation via a variety of methods including longitudinal fission, where the original anemone splits across the middle forming two equal-sized anemones, and basal laceration, in which small parts of the animal split from the base to form new anemones. Echinoderms. In echinoderms, the process is usually known as fissiparity (a term also used infrequently for biological fission in general). Some species can intentionally reproduce in this  manner through autotomy. This method is more common during the larval editing stages. Disadvantage of this process of reproduction. As this process is a form of asexual reproduction, it does not produce genetic diversity in the offspring. Therefore, these are more vulnerable to changing environments, parasites and diseases.