Talk:Evolution of sexual reproduction

message: 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)
replies: text: 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)
thread_title:  Paragraph in section 5.2 needs fixup 

message: at Evolutionary theory of sex--Filll 23:09, 26 July 2007 (UTC)
thread_title: Need editing assistance

message: 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)
replies: text: 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)
thread_title:  Crucial importance of sexual selection dynamics forgotten here. 

message: Has the mystery of sex been explained at last? 
http://www.newscientist.com/article/mg20227121.600-has-the-mystery-of-sex-been-explained-at-last.html?full=true
Stikko (talk) 12:30, 15 June 2009 (UTC)
thread_title:  New Scientist article: Has the mystery of sex been explained at last?  

message: 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.  --91.55.208.202 (talk) 00:09, 27 January 2010 (UTC)
replies: text: 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. --78.94.216.65 (talk) 07:34, 4 October 2010 (UTC)

text: Maynard Smith's 'twofold cost of sex' argument assumes that an unmated parthenogetic female can produce (on average) as many surviving offspring as the female in a male-female pair reproducing sexually.  If this is the case, then a gene mutation which causes a female to reproduce parthenogenetically, in an otherwise sexually reproducing population, will initially have twice as many replicas in the next generation as its 'sexual' competitors, and will therefore rapidly replace them.  The underlying assumption is valid if, other things being equal, the males in a sexually reproducing pair contribute nothing other than genetic material to their offspring.  Maynard Smith made this assumption because in a large majority of species it is true:  in all plants (I can't offhand think of any exceptions) and most animals.  The assumption fails in cases where the male provides significant resources either to the female before reproduction or in parental care to the offspring.  Parental care by the male parent is comparatively rare except among birds and some mammals, including humans.  Our human bias may lead us to overestimate the importance of paternal care among organisms generally. Maynard Smith was quite explicit about all this.2A00:23C8:7907:4B01:6476:F527:DF75:76B2 (talk) 20:19, 14 June 2023 (UTC)
thread_title:  Cost of sex 

message: 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 77.185.82.62 (talk) 20:21, 18 March 2010 (UTC)
thread_title:  Number of produced offspring is irrelevant 

message: 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 Khanhttp://news.nationalgeographic.com/news/2003/02/0214_030214_genghis.html, 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 118.151.208.163 (talk) 19:49, 20 April 2015 (UTC)
thread_title:  Responce to Number of produced offspring is irrevelent 

message: 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 98.87.122.104 (talk) 04:02, 22 August 2011 (UTC)
replies: text: Maynard Smith's 'twofold cost of sex' argument assumes that an unmated parthenogetic female can produce (on average) as many surviving offspring as the female in a male-female pair reproducing sexually.  If this is the case, then a gene mutation which causes a female to reproduce parthenogenetically, in an otherwise sexually reproducing population, will initially have twice as many replicas in the next generation as its 'sexual' competitors, and will therefore rapidly replace them.  The underlying assumption is valid if, other things being equal, the males in a sexually reproducing pair contribute nothing other than genetic material to their offspring.  Maynard Smith made this assumption because in a large majority of species it is true:  in all plants (I can't offhand think of any exceptions) and most animals.  The assumption fails in cases where the male provides significant resources either to the female before reproduction or in parental care to the offspring.  Parental care by the male parent is comparatively rare except among birds and some mammals, including humans.  Our human bias may lead us to overestimate the importance of paternal care among organisms generally. Maynard Smith was quite explicit about all this.2A00:23C8:7907:4B01:6476:F527:DF75:76B2 (talk) 20:19, 14 June 2023 (UTC)
thread_title: Two-fold cost of sex vs. cost of males

message: 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.--87.162.34.180 (talk) 17:20, 8 March 2010 (UTC)
thread_title:  why/how 

message: 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 (talk • contribs) 13:06, 13 March 2010 (UTC)
thread_title:  The disadvantage of haploid versus diploid gametes 

message: 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)
thread_title:  Fig 3 legend (epistasis) is wrong 

message: 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 173.189.75.207 (talk) 21:40, 8 May 2013 (UTC)
thread_title:  The Introduction is mostly irrelevant to the subject 

message: "Copulation in antiarch placoderms and the origin of gnathostome internal fertilization" .  With a related simplified article . 76.10.128.192 (talk) 23:29, 20 October 2014 (UTC)
thread_title:  May be of interest 

message: 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)--J. M. Mancebo Quintana (talk) 10:38, 27 February 2016 (UTC)
thread_title:  The twofold cost of sex: Studies that question the original approach 

message: 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)
replies: text: 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)
thread_title:  Merge from Evolutionary Theory of Sex (ETS) 

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

message: 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 93.227.23.210 (talk) 11:39, 8 December 2016 (UTC)
replies: text: 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)
thread_title:  What does this even mean? 

message: The following was recently removed as recentism ():
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)
thread_title:  Recentism? 

message: The long article:  "Interaction-based evolution: how natural selection and nonrandom mutation work together" by Adi Livnat https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4231362/ (which amazingly is not behind a paywall) presents a new theory that addresses all the traditional problems about sexual evolution, and evolution in general.  He wrote this in 2013.  While it may be too early to present it as settled science, it is deeply profound and comprehensive and is the first big step forward in evolutionary theory since the discovery of DNA (in my opinion).  He dispatches the question of how sexual reproduction arose and still survives when asexual reproduction is so much more efficient by explaining why evolution can't proceed from asexual reproduction and never has.  All organisms evolved entirely via sexual evolution, except for small tweaks in asexual organisms since the time they lost the ability to reproduce sexually. Losing the ability may introduce beneficial efficiencies, but is an evolutionary dead-end. This means that sexual reproduction predates asexual reproduction and is the original mode of reproduction.  Nearly all creatures bear the "cost" of sex because it is the only way to evolve.  He explains some about how multiple alleles are necessary at the population level for new functionality to converge.  But he also presents many other reasons; this is just the tip of the iceberg of Livnat's theory, which is really about the writing phenotype, which is the concept that much of our genome is focused on long-term evolution that takes millions of years to yield results.  Organisms have complex DNA-editing mechanisms that piece new de novo genes together from parts with no benefit to the individual until many generations have passed, and the pieces used to build these new genes come from other genes and the 80% of the genome currently labeled "junk DNA". This theory stipulates that although evolution is ultimately blind, it has been gathering tricks to maximize the use of collected information and the chances of building useful genes by elevating the building blocks of mutation from single base-pairs to large pre-built "erector set" sections that give preference to the most successful sections and take many lives to yield results. Junk genes and DNA that do nothing yet are in fact being selected for over a longer time frame, and evolution is patient for that result only because these long-term strategies evolved and outcompeted much less effective point-mutation strategies back at the dawn of life.  And he explains how males and sperm are largely the instruments of the writing phenotype, and much more.  It really needs to be turned into a best-selling book!
I would appreciate it if someone qualified would review Livnat's article and include a summary in this Wikipedia page, referencing the summary from the opening paragraph.  I could do it, but I am reluctant to proceed in an area I haven't formally studied for 35 years.  — Preceding unsigned comment added by 74.89.153.89 (talk) 15:48, 30 September 2018 (UTC)
replies: text: Interesting and the importance of sexual selection is also understood in mainstream biology.  If you can find secondary or tertiary sources discussing that material, we could use those.  Primary sources are discouraged and Wikipedia is not the place to promote papers or books, of course.  —PaleoNeonate – 16:08, 30 September 2018 (UTC)
thread_title:  Adi Livnat's "interaction-based evolution" theory makes most of this Wikipedia article obsolete 

message: This article does not actually provide what the title suggests, namely: a description of the evolution of sexual reproduction. 
It remains stuck in pro's and cons of sexual reproduction, hypothesises of why it even originated. 
What remains left out is any information on for example the transition from external to internal fertilisation (https://www.nature.com/news/fossils-rewrite-history-of-penetrative-sex-1.16173) i.e. the origins of penetrative sex. 
Neither does it address the plain fact that sexuality refers to a division in two sexes, and the entire evolutionary consequences of the existence of two sexes, or what is specific to the one sex and what to the other. 
I would suggest renaming this article "origins of sexual reproduction", and creating a new one named "Evolution of sexual reproduction", where the relevant themes such as the splitting in two sexes and implications of that are explained, as well as the evolutionary steps from the origins until the present state of sexual reproduction.
Lastly, I see it as a possibility that the lacking information is related to the fact that above mentioned topics are partly still taboo, even in the scientific world.  — Preceding unsigned comment added by FreieFF (talk • contribs) 12:44, 11 October 2019 (UTC)
thread_title:  Origin or Evolution? 

message: The questions section seems odd and not needed.
Also I have read some of those sources, it aren’t really asking questions. So that section is technically original research.CycoMa (talk) 22:30, 30 August 2021 (UTC)
thread_title:  The questions section  

message: It seems to me that little is made of the fundamental asymmetry between the sexes in that females contribute the mitochondria without recombination. In fact it could be said that all sexual reproduction includes asexual reproduction of the mitochondria.
We have a natural experiment going on in comparing the evolution of both genomes so surely this is worth at least a mention. Francishayden (talk) 18:02, 9 July 2022 (UTC)
thread_title:  Mitochondria not included 

message: About 90% of this article is verbose word spaghetti about the potential benefits of sexual reproduction, which is irrelevant to how sexual reproduction could develop step-by-step through mutation (it can't)
You'd think you could be more humble and upfront that it's an unanswered mystery to the scientific community, rather than hiding behind verbose word vomit that starts with the assumption that your favorite religion Darwinism is true. 174.57.221.108 (talk) 09:44, 11 July 2023 (UTC)
thread_title:  Extremely verbose without saying anything relevant or valuable. 

message: In Hymenoptera the males are haploid, so there can be no hidden deleterious mutations, yet the order is the most diverse among the insects.
Consequently Hymenoptera are not at risk from inbreeding depression.
This makes it easy for a single female to establish a population outside its range.
I suspect this also allows social insects to evolve large colonies. BioImages2000 (talk) 12:02, 23 July 2023 (UTC)
thread_title:  Hymenoptera