Online sex came
This implies that an asexual population has an intrinsic capacity to grow more rapidly with each generation.The cost was first described in mathematical terms by John Maynard Smith.This, however, conflates sex and reproduction which are two separate events.The "two-fold cost of sex" may more accurately be described as the cost of anisogamy. There are numerous species which are sexual and do not have this problem because they do not produce males or females.It is widely believed that a disadvantage of sexual reproduction is that a sexually reproducing organism will only be able to pass on 50% of its genes to each offspring.This is a consequence of the fact that gametes from sexually reproducing species are haploid.On the other hand, Charles Darwin (1809-1882) concluded that the effects of hybrid vigor (complementation) "is amply sufficient to account for the ... This is consistent with the repair and complementation hypothesis, given below under "Other explanations". In most multicellular sexual species, the population consists of two sexes, only one of which is capable of bearing young (with the exception of simultaneous hermaphrodites).
Since hypotheses for the origins of sex are difficult to test experimentally (outside of Evolutionary computation), most current work has focused on the maintenance of sexual reproduction.
Evidence that the cost is surmountable comes from George C.
Williams, who noted the existence of species which are capable of both asexual and sexual reproduction, such as certain lizards.
These species time their sexual reproduction with periods of environmental uncertainty, and reproduce asexually when conditions are more favourable.
These species are observed to reproduce sexually when they could choose not to, implying that there is a selective advantage to sexual reproduction.