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Asexual reproduction is found in nearly half of the animal phyla. [57] Parthenogenesis occurs in the hammerhead shark [ 58 ] and the blacktip shark . [ 59 ] [ 60 ] In both cases, the sharks had reached sexual maturity in captivity in the absence of males, and in both cases the offspring were shown to be genetically identical to the mothers.
Asexual reproduction in starfish takes place by fission or through autotomy of arms. In fission, the central disc breaks into two pieces and each portion then regenerates the missing parts. In autotomy, an arm is shed with part of the central disc attached, which continues to live independently as a "comet", eventually growing a new set of arms.
Since the reproduction is asexual, the newly created organism is a clone and, excepting mutations, is genetically identical to the parent organism. Organisms such as hydra use regenerative cells for reproduction in the process of budding. In hydra, a bud develops as an outgrowth due to repeated cell division of the parent body at one specific site.
Binary fission is generally rapid, though its speed varies between species. For E. coli, cells typically divide about every 20 minutes at 37 °C. [11] Because the new cells will, in turn, undergo binary fission on their own, the time binary fission requires is also the time the bacterial culture requires to double in the number of cells it ...
In general for fungi there are two main types of sexual reproduction: homothallism, when mating occurs within a single individual, or in other words each individual is self-fertile; and heterothallism, when hyphae from a single individual are self-sterile and need to interact with another compatible individual for mating to take place ...
Amitosis, also known as karyostenosis, direct cell division, or binary fission, is a form of asexual cell division primarily observed in bacteria and other prokaryotes. This process is distinct from other cell division mechanisms such as mitosis and meiosis , mainly because it bypasses the complexities associated with the mitotic apparatus ...
Vegetative methods of algal reproduction include sinple cell division, fission, fragmentation, splitting of colonial forms, hormogonia, vegetative bodies, formation of adventitious branches, tubers, and budding. Sexual methods of algal reproduction include isogamy, anisogamy, oogamy, autogamy, and hologamy. Autospores are one of three primary ...
It is an almost universal attribute of polyps to reproduce asexually by the method of budding. This mode of reproduction may be combined with sexual reproduction, or may be the sole method by which the polyp produces offspring, in which case the polyp is entirely without sexual organs. [1]