Talk:Evolution of sexual reproduction

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Former good article Evolution of sexual reproduction was one of the Natural sciences good articles, but it has been removed from the list. There are suggestions below for improving the article to meet the good article criteria. Once these issues have been addressed, the article can be renominated. Editors may also seek a reassessment of the decision if they believe there was a mistake.

Paragraph in section 5.2 needs fixup[edit]

This paragraph in section 5.2 needs to be fixed up, because it doesn't make sense at the moment.

There has been much criticism of Kondrashov's theory. First, it requires a very high mutation rate – one mutation per generation, which there is some empirical evidence for it (for example in Drosophila[14] and E. coli[15]). Second, it also requires deleterious mutations to act in a synergistic way. While there is some evidence for this kind of mutation – fitness relation – there is also the same amount of evidence that mutations do not act synergistically. Instead, there may be no epistatis (one mutation does not influence another) or antagonistic interaction (each additional mutation has a disproportionally small effect).

The second sentence doesn't make sense. I'm not going to touch it because I don't know what it's trying to say, but someone more versed in the matter might be able to fix it up. Maelin (Talk | Contribs) 04:40, 5 February 2007 (UTC)

I've modified the paragraph a little. Might make more sense now. Although might still not be perfect. suggestions are welcomed if it is still unclear. --Seb951 21:05, 15 February 2007 (UTC)

Need editing assistance[edit]

at Evolutionary theory of sex--Filll 23:09, 26 July 2007 (UTC)

distinguishing sex as a special case of recombination[edit]

This is a worthy article. However, it confuses the evolution of sex and the evolution of recombination. I would be happy to help edit the article, but wanted to get some agreement on how to proceed. This article is mostly about the advantages of recombination and the disdvantages of sex, both of interest, but somewhat conflated. More careful parsing of the effects of recombination (two parents) and sex (males and females) is in order. Worth noting, a proper accounting of the dis/advantages makes explaining sex more difficult.

Shall I have a go at it or is more coordination required?

By all means have a go. As a note, this article needs more high-quality citations, so your help there would also be appreciated. This tool lets you paste in a PMID and gives you a formatted reference. You might find it useful. All the best Tim Vickers 23:17, 4 August 2007 (UTC)
Recombination does not imply two parents - frequently a hermaphrodite is capable of reproducing sexually with itself, bacteria conjugate (recombine their DNA) without reproducing.
Perhaps this article needs to be moved to Evolution of sexual reproduction, since it is about sexual reproduction, not about the definition presented at sex (although that alternative definition is included in the "sexual reproduction" definition). LyrlTalk C 13:52, 5 August 2007 (UTC)

Crucial importance of sexual selection dynamics forgotten here.[edit]

Here it is again. A discussion of “why sex?” that covers every base except what is probably the most important: sexual selection. Just about every lay introduction to natural selection will utilize as prime examples traits such as opposable thumbs and beak shapes. I would argue that sexual selection is of crucial importance to evolution and over the last 100 thousand years has been of far greater importance than traits developed through interaction with purely physical forces such as heat, cold, and resistance to bacteriological elements. In sexual selection, the woman will typically prefer men with a good balance of strength and gentleness, being cognisant that she expects him to help rear their children. As a result, women characteristically are attracted to strength, but not to sadism, to affluence, but not to meanness, to a sense of humour, because a man with a sense of humour will be more likely to be charmed by the activities of their children, and so on. In an oral society, a well-spoken man will receive preferential treatment when compared to one who is tongue-tied. A man who has “people-skills” and can handle and lead people will attain personal power that others will not. Traditionally, people who attain privileged positions have greater choices available to them, in terms of who they marry, in terms of provision for their children. In this way, such behavioural and personality traits can become fixed in a community through the simple functioning of selection pressure via sexual and cultural selection. Yet these mechanisms are given short shrift in the literature of evolution. Sexual attraction between the genders is the next best thing to direct phenome to genome transfer. In effect, a strong, intelligent man is given his procreational advantages on credit, as it were, just as a fertile, intelligent woman is given hers. I often wonder why these HUGE affects are forgotten by writers, in favour of such piddling ones as resistance to parasites. Is it because evolutionary pressure from within society sounds less “scientific”? Myles325a 05:49, 16 August 2007 (UTC)

This article is about the evolution of sexual reproduction. Multitudes of very simple organisms (e.g. ants, who do not express mate preference) or solitary organisms (e.g. lizards) reproduce sexually, and the fact that they continue to reproduce sexual rather than developing asexual reproductive mechanisms is what this article is focused on. Sexual selection is a completely separate article. LyrlTalk C 21:06, 16 August 2007 (UTC)

New Scientist article: Has the mystery of sex been explained at last?[edit]

Has the mystery of sex been explained at last? Stikko (talk) 12:30, 15 June 2009 (UTC)

Cost of sex[edit]

There are fallacies in the picture as well as in the description:

"If each individual were to contribute to the same number of offspring (two), (a) the sexual population remains the same size each generation, where the (b) asexual population doubles in size each generation."

Well, doh. If each individual were to contribute to double the number, the sexual population also doubles in size. They can do that because they are twice as many individuals, sharing the cost.

"This implies that an asexual population has an intrinsic capacity to grow more rapidly each generation."

No, it doesn't.

Note that I don't comment on whether or not the basic premise is true, just that the explanations are fallacious. -- (talk) 00:09, 27 January 2010 (UTC)

This should probably be reworded to something along the lines of "each individual/pair contributing to the next generation". Within sexual reproduction you obviously need two individuals. If this pair then to produce two offspring then they each produce a single "replacement", as it were. Within asexual reproduction, the individual merely divides creating two "offspring", in essence creating one "replacement" and a second offspring which adds to the next generation. So we have sexual reproduction as 1+1(2)>2, number of offspring=number of breeding individuals vs. assexual reproduction as 1>1+1(2), number of offspring=2*(number of breeding individuals). The initial statement could easily be misread and does need to be made clearer. - Wikim3 04:11, 24 February 2010 (UTC) —Preceding unsigned comment added by (talk)

Well, what also struck me was the fact that hermaphrodites are mentioned briefly but then not talked about at all. The cost is not so much about sexual reproduction but about half of the individuals not being able to put energy into eggs/pregnancy and for some species not even into raising the young. Hermaphrodites do not exhibit this disadvantage and it is therefore not so much a puzzle to me why sexual reproduction developed but why it didn't generally develop into a hermaphroditic form. The actual number of offspring could then still be reduced for species that need more effort to be put into each of their young. -- (talk) 07:34, 4 October 2010 (UTC)

Number of produced offspring is irrelevant[edit]

Fallacies I see in "Cost of sex": The long term replacement rate for every species on Earth is one. Because if not, you would get exponential growth and earth couldn’t support this. Beside this the number of offspring, who reach the phase of adulthood, is more dependent on the resources and perils of the environment. And not on the number of offspring produced by the parents.

The only disadvantage I see for sexual reproduction is, that a pair of individuals has to meet each other to reproduce. —Preceding unsigned comment added by (talk) 20:21, 18 March 2010 (UTC)

Responce to Number of produced offspring is irrevelent[edit]

Although your premise that one would get exponential growth if the long-term replacement rate is not one, your conclusion is invalid. This is because having one child (if you are asexual) or two (if you are sexual) does not gaurantee that in the long-term, your genes will be preserved, albeit in different organisms in case of sexual reproduction. The individual with the largest number of healthy, fertile offspring has the largest chance of being represented in the gene-pool in the long-run. To make this clear, it has been found that 1 in 200 men are direct descendents of Genghis Khan[1], who lived about a 1000 years ago. Your conclusion would make sense only if there were only 200 men at the time. — Preceding unsigned comment added by (talk) 19:49, 20 April 2015 (UTC)


Two-fold cost of sex vs. cost of males[edit]

This section does have several weaknesses, already noted. I think one basic issue is that the term "two-fold cost of sex" is misleading, albeit popular in the literature. I prefer the original term, which is the cost of males - it more precisely identifies the problem as the presence of a significant proportion of the adult population that is required for reproduction to occur, but does not itself reproduce; although Maynard Smith did show that this advantage is two-fold under the assumptions of his example, it can safely be assumed that this cost will vary depending upon a number of factors, such as mating system specifics, presence of hermaphroditism, prevalence of sex in the life cycle (i.e. if it is not obligate), etc.

And on that note, the combination of the reference to Maynard Smith being the first to mathematically describe the cost of males is juxtaposed with a nonsense graphic that, first of all, bears no resemblance at all to the schematic that accompanied his mathematical description, and second of all, erroneously gives the impression that a sexual population does not increase in size at all! "Two-fold" implies that the rate of increase is twice as great for the asexuals; the figure does not illustrate this. Maynard Smith's own diagram can be found in his book, which is in any decent science library.

Sexual selection is completely out of place in this section; the costs of sexual selection are completely irrelevant to the specifics of the two-fold cost of sex/cost of males. Sexual selection is worthy of attention, but it is a separate matter. Changing the section title to "Disadvantages/Costs of Sex" would make the inclusion more appropriate, along with the other disadvantages.

The paragraph claiming that evidence that the cost of sex can be overcome comes from George C. Williams makes no sense; the evidence that the sex can be overcome is that sex is utterly dominant as a reproductive mechanism in multicellular eukaryotes. One of Maynard Smith's major points in describing the cost of males was in contrasting the ubiquity and obvious success of sex, which evolutionary biologists had heretofore taken largely for granted, with the fact that it simply does not work according to standard population genetics. The paragraph describes a specific hypothetical advantage to sexual reproduction, which is often referred to as the "lottery ticket argument," since that was the analogy Williams used to make the point.

I apologize, because these points will seem "old-fogeyish," though I wish to return to make these edits, if someone does not beat me to it.

-colbyg (talk) 04:02, 22 August 2011 (UTC)


This article needs restructuring. I came here looking for how sex evolved, but that part is hidden away at the end in sections 7-8. It's also very short. Most of the article talks about possible explanations why sex evolved (or what for) and historical perspectives on that. The introduction doesn't talk about the how at all. IMO an article entitled "Evolution of sexual reproduction" should first describe what we know about how it happened, and then go on to speculate about why sex is an evolutionary gain.-- (talk) 17:20, 8 March 2010 (UTC)

The disadvantage of haploid versus diploid gametes[edit]

Good article. One of the main costs of sexual reproduction according to Matt Ridley in his book "The Red Queen", is that of sacrificing the passage of half of your genes into the next generation. I was expecting to find this fact noted in this piece but as I couldn't find it I added it. —Preceding unsigned comment added by RichardAndrewNevin (talkcontribs) 13:06, 13 March 2010 (UTC)

Fig 3 legend (epistasis) is wrong[edit]

I believe the legend to Fig 3 is seriously wrong: the red convex line is the synergistic epistasis case (required for Kondrashov's theory), since here 2 mutations have bigger effects than the sum of the effects of each individually. The concave blue line shows antagonistic epistasis. See Ridley's "Mendel's Demon" book.Paulhummerman (talk) 14:26, 18 October 2011 (UTC)

Yes, I have another Ridley book, Evolution, 3rd edition; it agrees (well, it would)... I take it he knows what he's talking about. Evercat (talk) 19:59, 29 November 2011 (UTC)

Also Charlesworth and Charlesworth, Elements of Evolutionary Genetics. I think it should really be log(fitness) on the y axis. Evercat (talk) 20:10, 29 November 2011 (UTC)

In fact yes, I very strongly believe it needs to be log(fitness) on the y axis... Evercat (talk) 22:58, 30 November 2011 (UTC)

The Introduction is mostly irrelevant to the subject[edit]

This article's subject is the evolution of sexual reproduction. 1. The introduction claims (correctly) that there is no consensus and then proceeds to ignore the evolution to speak about the maintenance of sexual reproduction. I should NOT have to delve into the rest of the article to learn about the theories/hypotheses, should I ?? 2. The introduction claims that all eukaryotes which reproduce sexually have a common ancestor. How is that reconciled with the species that reproduce both asexually and sexually? Are we sure that sex only evolved once? Given that most of the intro makes a strong case for its reproductive value, then either it must be linked to the cell wall (definition of Eukaryotes) or did not just evolve once. Have all asexually reproducing eukaryotes been shown to have sexual ancestors? {I am not well informed on this issue, please take my comments to indicate areas where the introduction fails to inform the average reader}. Is this well established (fact) or a working hypothesis/ assumption? What about the sexual prokaryotes? 3. The introduction should define what sexual reproduction is, to start out. It doesn't even mention the fact that it is between two (or more) individuals, that the sex of an individual may vary over its lifetime, and that its sex may be environmentally determined. It also doesn't mention the fact that the number of sexes ranges between 2 and ?? (I'm not sure, at least 3) 4. DNA is barely mentioned, and only in the context of repair. 5. If you threw out the "maintenance of sexual reproduction" part of the introduction, there would be almost nothing left. In my opinion, most people will come here NOT to learn about how sexual reproduction is evolving or contributing to the evolution of a species, but to learn about how it developed to begin with. Logically, origin should precede maintenance/continuing development processes. 6. I recommend a rewrite, focusing on the basics: What, who, when, why, and how. Overview (What is sex, who has it (which Domains & Kingdoms?) History when did it evolve? (NOT to be confused with the history of the study of it) Why and how did it evolve? If you really can't speak clearly to its causal origin, then you should speak in terms of it surviving originally because of utility. — Preceding unsigned comment added by (talk) 21:40, 8 May 2013 (UTC)

May be of interest[edit]

"Copulation in antiarch placoderms and the origin of gnathostome internal fertilization" [1]. With a related simplified article [2]. (talk) 23:29, 20 October 2014 (UTC)

The twofold cost of sex: Studies that question the original approach[edit]

There is at least one published paper that questions the twofold cost of sex or the cost of males (as preferred): The False Problem of the Maintenance of Sex (Review of the Original Approach)[1]--J. M. Mancebo Quintana (talk) 10:38, 27 February 2016 (UTC)


  1. ^ Mancebo Quintana, Jose Maria (2014). "The False Problem of the Maintenance of Sex (Review of the Original Approach)". Applied Mathematics. 05 (19): 3135–3155. doi:10.4236/am.2014.519297. 

Merge from Evolutionary Theory of Sex (ETS)[edit]

The article at Evolutionary theory of sex (ETS) was a very dodgy essay. Not at all encyclopedic, and with very little worth merging here. I've simply made it a redirect. It seems to me that someone has been trying to push Trofimova's views into any articles that they could, and giving them plenty of undue weight. --Slashme (talk) 16:35, 22 July 2016 (UTC)

From the user KaiStr: I disagree with the merge of this page and with Slashme devaluation of this page. This ETS theory existed since the 1960s, within a rather strong evolutionary school (Russians evolutionary biologists), and the author of the ETS is a completely different person (Geodakyan). Trofimova only adopted this ETS theory to psychology but she wasn't the author of the original theory. The page was encyclopedic as it had definitions and illustrations - borrowed from Trofimova for simplicity. Please don't bring your prejudice and ignorance to wikipedia, let public see all opinions and theories offered within different (an not just yours) schools. KaiStr (talk) 06:11, 24 July 2016 (UTC)

The undue weight would be to merge. Making redirects from pages with non-standard titles is not good idea. Staszek Lem (talk) 17:54, 8 August 2016 (UTC)

Geodakyan's evolutionary theory of sex[edit]

Please check out this new article, Geodakyan's evolutionary theory of sex. Staszek Lem (talk) 18:09, 27 July 2016 (UTC)

Geodakyan's evolutionary theory of sex EXPERTS WHERE are YOU? HELOOOOO![edit]

Help required with Geodakyan's evolutionary theory of sex desperately: the article of apparently fringe theory is based almost exclusively on primary sources and edited by a people with strong connection to the subject. Staszek Lem (talk) 17:07, 13 October 2016 (UTC)

You're probably right that an expert in the domain is needed, and it seems none is to hand. However, perhaps the rest of us can make a few pertinent remarks. Firstly, Geodakyan's published articles on the evolution of sex go back a very long way, one paper being from 1968 (if that's not a typo) with a dissertation in 1987. Secondly, these publications have mostly been cited by very few others; his 1991 Evolutionary theory of sex had as many as 17, but all of these were by Russian authors, 3 of them by someone named Geodakyan (him or his wife, perhaps), so it seems acceptance of his views by scientists in the west is very limited. Thirdly, he self-published ( The Evolutionary Theory of Sex on Lulu, an unusual publicity move for a scientific paper published long before. The overall picture does hint at WP:FRINGE, though since his ideas look as though they are falsifiable, they are not necessarily unscientific.
On the article itself, it looks as if it's been edited by someone who is not a native speaker of English, maybe a colleague or friend of Geodakyan (d 2012), who knows.
Is it notable as a theory? I'd say it was borderline; at an AfD, I think I'd vote to merge the article with Evolution of sexual reproduction, where I'd give it a sentence or two. Just my tuppence worth. Chiswick Chap (talk) 18:01, 13 October 2016 (UTC)
Thank you for your input, but I am interested in someone helping with maintaining the article. I don't mind keeping it, since I find it interesting and the author did have visibility in Soviet times and places, but I want it to be free of undue promotion and further original research. Unfortunately the "page owners" are extremely uncooperative and impolite, to put it mildly, although I keep ignoring their attacks. Staszek Lem (talk) 19:22, 13 October 2016 (UTC)
P.S. Yes it dates from 1960s; as for Lulu, it seems it was published by his son. Staszek Lem (talk) 19:22, 13 October 2016 (UTC)
See also Wikipedia:Articles for deletion/The Principle of Conjugated Subsystems. Staszek Lem (talk) 19:28, 13 October 2016 (UTC)

What does this even mean?[edit]

Males adopt strategies with lower investment in individual gametes and may present a higher mutation rate,[citation needed] while females may invest more resources and serve to conserve better-adapted solutions.[citation needed]

Apart from being completely citation needed it mixes together nursing strategies and mutation rates. How are they related? And what are the benefits of high/low mutation rates? I don't understand at all what this section is trying to say. — Preceding unsigned comment added by (talk) 11:39, 8 December 2016 (UTC)

An individual can employ different strategies in order to maximize reproduction. Either you can make lots of babies at a small cost for each baby, or you can make fewer babies and invest more in trying to make each offspring survive, see Life history theory and R/K_selection_theory. In at least some species males have higher mutation rates than females. The reason why it may be beneficial for males to have a higher mutation rate is that each male is worth less for the survival of the species than each female. If one male dies from a bad mutation, this doesn't matter as much, since other males can easily compensate by producing more offspring. Conversely, a beneficial mutation in a male will spread quicker than a in a female. Koyos (talk) 16:06, 2 April 2017 (UTC)


The following was recently removed as recentism (diff):

"However, research published in 2015 indicates that sexual selection can explain the persistence of sexual reproduction in animals.[1]"


While I agree that 2015 is rather recent, and that the wording may possibly have been in undue weight or misplaced, after reading the source I found nothing particularily questionable. While research is of course still ongoing, it seems to already have been common knowledge to me that there can be advantages of sexual selection. The text which follows also appears to reflect this. I therefore don't see this as being recentism, but among the plausible hypotheses related to sexual selection. Thanks, —PaleoNeonate - 22:41, 16 June 2017 (UTC)