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Sexual reproduction is the most common life cycle in multicellular eukaryotes, such as animals, fungi and plants. [6] [7] Sexual reproduction also occurs in some unicellular eukaryotes. [2] [8] Sexual reproduction does not occur in prokaryotes, unicellular organisms without cell nuclei, such as bacteria and archaea.
The Komodo dragon, which normally reproduces sexually, has also been found able to reproduce asexually by parthenogenesis. [54] A case has been documented of a Komodo dragon reproducing via sexual reproduction after a known parthenogenetic event, [ 55 ] highlighting that these cases of parthenogenesis are reproductive accidents, rather than ...
Some species reproduce exclusively by parthenogenesis (such as the bdelloid rotifers), while others can switch between sexual reproduction and parthenogenesis. This is called facultative parthenogenesis (other terms are cyclical parthenogenesis, heterogamy [ 14 ] [ 15 ] or heterogony [ 16 ] [ 17 ] ).
Sexual systems play a key role in genetic variation and reproductive success, and may also have led to the origin or extinction of certain species. [4] In flowering plants and animals, sexual reproduction involves meiosis, an adaptive process for repairing damage in the germline DNA transmitted to progeny. [5]
By asexual reproduction, an organism creates a genetically similar or identical copy of itself. The evolution of sexual reproduction is a major puzzle for biologists. The two-fold cost of sexual reproduction is that only 50% of organisms reproduce [1] and organisms only pass on 50% of their genes. [2]
A species (pl.: species) is a population of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. [1] It is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity.
Parthenogenesis is a mode of asexual reproduction in which offspring are produced by females without the genetic contribution of a male. Among all the sexual vertebrates, the only examples of true parthenogenesis, in which all-female populations reproduce without the involvement of males, are found in squamate reptiles (snakes and lizards). [1]
Animal – multicellular eukaryotic organisms that form the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, reproduce sexually, and grow from a hollow sphere of cells, the blastula, during embryonic development. Subkingdom Parazoa. Porifera; Placozoa; Subkingdom Eumetazoa ...