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( Parthogenesis)
Parthenogenesis (from the Greek pa?????? parthenos, "virgin", + ???es?? genesis, "creation") is an asexual form of reproduction found in females where growth and development of embryos or seeds occurs without fertilization by a male. The offspring produced by parthenogenesis almost always are female in species where the XY chromosome system determines sex. Parthenogenesis occurs naturally in some species, including most lower plants, a Kalanchoe succulent plant genus of South Africa, invertebrates (e.g. water fleas, aphids, some bees, some scorpion species, and parasitic wasps), and vertebrates (e.g. some reptiles,[1] fish, and, very rarely, birds[2] and sharks[3]) and this type of reproduction has been induced artificially in other species. The term is sometimes used inaccurately to describe reproduction modes in hermaphroditic species which can reproduce by themselves because they contain reproductive organs of both sexes. Parthenogenesis is a form of asexual reproduction in which females produce eggs that develop without fertilization. Parthenogenesis is seen to occur naturally in aphids, daphnia, rotifers, and some other invertebrates, as well as in many plants. Komodo dragons and the hammerhead- and blacktip sharks have recently been added to the list of vertebrates—along with several genera of fish, amphibians, and reptiles—that exhibit differing forms of asexual reproduction, including true parthenogenesis, gynogenesis, and hybridogenesis (an incomplete form of parthenogenesis).
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