Gender evolution

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Discussion by: Schwarzbach
I have great respect for Richard Dawkins read a number of his books and some of Darwins. I am wondering if someone could answer this question?
1.)How did gender evolve at the beginning of life on the planet? How did it come about?.

32 COMMENTS

  1. Hopefully others will come along with references, but as I recall, organisms that reproduced with genetic contributions from more than one source adapted better than their rivals, so exchanging or combining genes became established.

    Then there emerged two winning strategies for genes to pass to the next generation: via something small cheap fast and plentiful (like sperm) or something big slow expensive and rare, but well supplied with the materials and energy to build a new organism (like eggs).

    The middle ground emptied out, leaving only the extremes – the faster, cheaper sperm out competed their slower, more expensive rivals. The large, expensive, well supplied egg likewise out competed smaller, cheaper but less well endowed rivals. For the two kinds to meet, only one has to move fast.

    Somewhere along the way, individual organisms grew specialised, one kind or the other, instead of having both sets of equipment. And lo, we had male and female.

    If someone else has a better, concise, plain English description of the evolution of sex, please share. I don’t think mine’s anywhere near as good as it could be. Hope it helps anyway.

  2. Before others spend a lot of effort trying to explain this, you can help yourself (#) by reading existing material on this subject that can be located by the obvious search. Here are two to begin with,

    Interestingly there is an article Evolutionary Theories On Gender And Sexual Reproduction
    © 2003 by Brad Harrub and Bert Thompson
    that ** criticizes ** various evolutionary explanations. It has a decent number of references to legitimate sources so it might be worth taking a look at. There is a long wikipedia article Evolution of sexual reproduction that addresses the topic directly.It has a large number of references.

    (#) The traditional phrase God helps those who help themselves and its interesting origins might be unfamiliar to some atheists. ;)

      • In reply to #4 by mmurray:

        In reply to #2 by whiteraven:

        (#) The traditional phrase God helps those who help themselves and its interesting origins might be unfamiliar to some atheists. ;)

        It’s been replaced by Let Me Google That For You

        Michael, This is an interesting topic but the lack of an emoticon leaves me unsure of your intent, therefore let me not google for you advice from FAQ > Discussions *Don’t post questions that you could find answers to yourself by doing a simple Google search or by doing some elementary reading”. :) Thanks for reminding me to provide a reference for something I had a vague recollection of. ;)

        • In reply to #6 by whiteraven:

          In reply to #4 by mmurray:

          It’s been replaced by Let Me Google That For You

          Michael, This is an interesting topic but the lack of an e…

          whiteraven it was supposed to be slightly humorous but I do find LMGTFY a useful site. You can answer a person’s question but at the same time give them a gentle prod about how they could have done it themselves.

          I did’t realise there was an FAQ. Thanks.

          Michael

          • In reply to #8 by mmurray:

            In reply to #6 by whiteraven:

            In reply to #4 by mmurray:

            It’s been replaced by Let Me Google That For You

            Michael, This is an interesting topic but the lack of an e…

            whiteraven it was supposed to be slightly humorous but I do find LMGTFY a useful site. You can answer a person’s question but a…

            Safari is not swallowing that link. These work: http://www.google.com or http://www.lmgtfy.com (Wolfram alpha for the masses? I’ll give it a try). If I enter search terms in Safari’s address bar, it feeds them to the default search engine (google, yahoo or bing)because of another discussion. LMGFY returned

            Oh, chances are I would only be looking for an FAQ if I was already here, I found it by “searching” the About tab dropdown menu on the home page. I tried y:our approach: open a tab to LMGTFY, enter [richard dawkins web site faq], it takes me to the home page, so I return to LMGFY and try [richard Dawkins faq] which gives the link to the FAQ page as the 2nd hit. I tried [explain death to an atheist child]. LMGTFY returned a good list of URLs, identical to a normal google on the same search terms.

          • In reply to #14 by whiteraven:

            In reply to #8 by mmurray:

            Safari is not swallowing that link.

            Ah sorry. It’s broken and I can’t get in an edit it now.

            Michael

          • In reply to #14 by whiteraven:

            LMGTFY returned a good list of URLs, identical to a normal google on the same search terms.

            I think that you miss the point of the LMGTFY site. It is an humorous site that allows you to create a link to show someone how to google a specific phrase. Just click the link below to see what it does.

            let me google that for you

          • In reply to #16 by halucigenia:

            In reply to #14 by whiteraven:

            LMGTFY returned a good list of URLs, identical to a normal google on the same search terms.

            I think that you miss the point of the LMGTFY site. It is an humorous site that allows you to create a link to show someone how to google a specific phrase. Just click the lin…

            Let’s put this dull-witted student’s understanding to the test:

            • To answer “How did gender evolve?” brings us to the origins of sexual reproduction. No small effort is required to find a point of departure for this daunting leap back to the very origins of life on Earth. Every journey requires a first step and ours will begin here.
  3. I think Matt Ridley’s book “The Red Queen” includes discussion of origins of sexual reproduction. Like why there’s a convergence to only 2 kinds of sexes in more complex organisms compared to bacteria, which exchange routinely exchange genetic information without having distinct genders.

    The book is mostly an explanation of how gender affects human psychology. Maybe like why members of some genders might be more or less likely to be inquisitive about the origins of gender. I think the book might have been considered controversial because it collides heavily with political correctness of various kinds.

    http://www.amazon.com/Red-Queen-Evolution-Human-Nature/dp/0060556579

    • In reply to #5 by Pete H:

      I think Matt Ridley’s book “The Red Queen” includes discussion of origins of sexual reproduction. Like why there’s a convergence to only 2 kinds of sexes in more complex organisms compared to bacteria, which exchange routinely exchange genetic information without having distinct genders.

      In connection with this, see hermaphroditic reproduction.

  4. @OP -
    1.)How did gender evolve at the beginning of life on the planet? How did it come about?.

    Some earlier comments have given good explanations and good links.

    However, many who ask this question, are only familiar with a limited range of bisexual Vertebrate (animal) reproduction.

    Tracking back the link to hermaphroditic reproduction @7 takes us to the precursor of separate sexes.

    Many eukaryotic (multicellular) species have both sexes in the same plant, fungus or animal, so the question is not “how did they evolve separately?” (as creationists like to ask), but how did organisms suppress the development one set of sex organs to become specialist males or females.
    An easily observable example is in flowering plants.

    What are dioecious and monoecious plants? Wiki-answers

    Answer:
    Dioecious plants have both the male and female reproductive organs on separate individuals of the same species while monoecious plants have separate male and female flowers on the same plant.

    Many single celled organisms do not have sexual reproduction at all, but simply use horizontal gene exchange of DNA.

    http://www.sci.sdsu.edu/~smaloy/MicrobialGenetics/topics/genetic-exchange/exchange/exchange.html

    What is Horizontal Gene Transfer?

    Natural genetic transformation is believed to be the essential mechanism for the attainment of genetic plasticity in many species of bacteria. During bacterial evolution, the ability of Bacteria and Archaea to adapt to new environments most often results from the acquistion of new genes through horizontal transfer rather than by the alteration of gene functions through numerous point mutations. Horizontal gene transfer is defined to be the movement of genetic material between bacteria other than by descent in which information travels through the generations as the cell divides. It is most often thought of as a sexual process that requires a mechanism for the mobilization of chromosomal DNA among bacterial cells. However, because they are unable to reproduce sexually, bacterial species have acquired several mechanisms by which to exchange genetic materials.

    • Transformation – the uptake of naked DNA is a common mode of horizontal gene transfer that can mediate the exchange of any part of a chromosome; this process is most common in bacteria that are naturally transformable; typically only short DNA fragments are exchanged.
    • Conjugation – the transfer of DNA mediated by conjugal plasmids or conjugal transposons; requires cell to cell contact but can occur between distantly related bacteria or even bacteria and eukaryotic cells; can transfer long fragments of DNA.
    • Transduction – the transfer of DNA by phage requires that the donor and recipient share cell surface receptors for phage binding and thus is usually limited to closely related bacteria; the length of DNA transferred is limited by the size of the phage head.

    Viruses also transfer DNA in their processes of hi-jacking the reproduction systems of host cells.

    Coming back to separate sex organs, the reproductive system of gastropods illustrates the diversity of developments.

    Reproductive system of gastropods Wiki

    The reproductive system of gastropods (slugs and snails) varies greatly from one group to another within this very large and diverse taxonomic class of animals. Their reproductive strategies also vary greatly.

    In many marine gastropods there are separate sexes (male and female); most terrestrial gastropods however are hermaphrodites.

    ▬▬▬▬▬▬▬

    Simultaneous hermaphrodites

    Within the main clade Heterobranchia, the informal group Opisthobranchia are simultaneous hermaphrodites (they have both sets of reproductive organs within one individual at the same time).

    ▬▬▬▬▬▬▬

    Separate sexes

    In many taxonomic groups of marine gastropods, there are separate sexes (i.e. they are dioecious).

    The great majority of species in some of the main gastropod clades have separate sexes. This is true in most of the Patellogastropoda, Vetigastropoda, Cocculiniformia, Neritimorpha, and Caenogastropoda.

    ▬▬▬▬▬▬▬

    Protandrous sequential hermaphrodites

    Within the clade Littorinimorpha however, the superfamily Calyptraeoidea are protandrous sequential hermaphrodites.

    Protandry means that the individuals first become male, and then later on become female. See for example the genus Crepidula.

    Some snails can even fertilise themselves and breed from a single individual!

    There are also fish species in which the individuals change sex during their lifetimes.

    • In reply to #9 by Alan4discussion:

      @OP -
      1.)How did gender evolve at the beginning of life on the planet? How did it come about?.

      Some earlier comments have given good explanations and good links.

      However, many who ask this question, are only familiar with a limited range of bisexual Vertebrate (animal) reproduction.

      Tracking bac…

      It will take time to read it carefully (I am not a biologist), but I find it funny that following the links I even found a reference to The Jurassic Park (actually I did wonder myself why did the offspring of those female dinosaurs have had offspring, and there was the explanation)

  5. Schwarzbach,

    Here’s another Wiki page that provides useful information for this discussion. It explains the difference between the words “gender” and “sex”. The article explains that sometimes these two words are used interchangeably in discussions such as the one you have initiated here, but I’ll point out that you will probably be corrected by someone in the future as to the distinction between the two words. Just personally, I try to keep them separate as much as possible to avoid confusion.

    http://en.wikipedia.org/wiki/Gender

    From the above Wiki article:

    Gender is a range of physical, mental, and behavioral characteristics distinguishing between masculinity and femininity.[1][2][3] Depending on the context, the term may refer to biological sex (i.e. the state of being male, female or intersex), social roles (as in gender roles), or gender identity.[1][2][3][4]

    Pete H,

    The book is mostly an explanation of how gender affects human psychology. Maybe like why members of some genders might be more or less likely to be inquisitive about the origins of gender. I think the book might have been considered controversial because it collides heavily with political correctness of various kinds.

    Yes, there is controversy all around this subject. This section from the same Wiki article above explains why.

    The social sciences have a branch devoted to gender studies. Other sciences, such as psychology, sexology and neuroscience, are also interested in the subject. While the social sciences sometimes approach gender as a social construct, and gender studies particularly do, research in the natural sciences investigates whether biological differences in males and females influence the development of gender in humans; both inform debate about how far biological differences influence the formation of gender identity.

  6. And of course then you have the slime moulds as explained on this fun page about sex:-

    The Wilder Side of Sex

    If you calculate all the possible combinations of genes and sex cells, you will find that Physarum have more than 500 different sexes. Reproduction for slime molds may be complicated, but it’s never boring.

    And since the OP is about how genders evolved you can’t ignore the fact that genders arose because sex arose as a way of two cells fusing to form one and as rightly has been stated there evolves a difference between the different types of cell that fuse. And simply put that is how gender evolved at the beginning of life on the planet – because differences evolved between the organisms that produced different types of cells that fuse (gametes).
    Males are defined as the organisms which produce small gametes and females the ones that produce large gametes.

    I suspect that the OP may have meant to ask how sex evolved though. So…

    What a lot of people fail to understand is that sex is not “for” reproduction – the process of an organism producing more organisms. Sex is the opposite of that, it is, as stated above, the fusing of two cells.

    I think that it helps, when looking a what sex is “for”, to understand the difference between diploid and haploid forms of a polyploid organism in it’s lifecycle.

    The dominant form of most organisms that we are familiar with is the diploid form – the one that is produced from fused gametes with a double compliment of each chromosome. Whereas the haploid form is the subordinate form – sperm and eggs with a single compliment of each chromosome.

    It is the other way around in some organisms such as in bryophytes (mosses and liverworts etc.), where the haploid gametophyte is the dominant form of the organism. For example the moss plant that we are familiar with is the gametophyte haploid form of the life cycle whereas the diploid form in the life-cycle is the temporary sporophyte that is produced by the sperm (yes mobile flagellate sperm in a plant) fertilising the egg (both of which, sperm and egg, have the same single complement of each chromosome as the main part of the moss plant). This temporary diploid sporophyte simply grows as a stalk on the gametophyte to produce a spore capsule that releases a huge amount of haploid spores which then are spread and go on to produce more haploid moss plants. So the zygote is just the gamete’s way of producing more gametes in mosses. :)

    Therefore, looking at it this way, the zygote just being the gamete’s way of producing more gametes even in polyploid dominant life cycles, you can see that sex is a way to enable a single cell to undergo meiotic cell division to be able to produce more gametic cells than would otherwise be possible in organisms with only a haploid phase.
    And from the point of view of evolution – the genes have a better chance of reproducing themselves with all of these gametic cells being spread around.

    Kind of turns things on it’s head to look at it this way doesn’t it?

    Of course the added benefit of this process is that mitosis can also occur if diploid cells are present in the lifecycle, so that different alleles (different forms of the same gene) can get mixed in individuals within a population which of course promotes diversity and increases the possibility of adaptation to novel niches etc.

    So conclusion of this is that this haploid/diploid sexually reproducing life-cycle, with distinct genders as a ‘by product’ of two winning strategies (as OHooligan puts it) , became evolutionarily successful once it arose.

    (Sorry if I appear to be rambling but I have a bit of a fever, but then sometimes inspiration comes from a fevered mind – ask Alfred Russel Wallace.) ;)

      • In reply to #12 by LaurieB:

        In reply to #11 by halucigenia:

        You joined this website in 2006? With a comment like the one you just posted, I’m baffled as to why you were lurking out there for so long. :-)

        I migrated along with some others some time ago but look in now and again. ;)

    • In reply to #11 by halucigenia:

      (Sorry if I appear to be rambling but I have a bit of a fever, but then sometimes inspiration comes from a fevered mind – ask Alfred Russel Wallace.) ;)

      Ah

      Here´s a piece of theatre with Alfred Russel writing a letter to Darwin, from Moluccas with a blanket on him (with fever).

      Darwin answered him by saying that the discoverie was their child (of both), but that Wallace should avoid putting it in terms of supernatural, I guess Wallace would be the ideal for some people, not Darwin.

  7. I find the OP to be a loaded question. Gender has not existed since the beginning of life on the planet. It came about through evolution. I smell an ulterior motive.

    If i am wrong, then the links below are great places to start. Also, Alan4 brings up an important need: the need to divorce yourself from the thought that gender is uniquely human….. or uniquely animal….. plants have gender…. bacteria have sex pili and F plasmids….. Yes, bacteria F each other.

    The garden is beautiful WITHOUT having to invent fairies at the bottom.

    • In reply to #18 by crookedshoes:

      I find the OP to be a loaded question. … I smell an ulterior motive.

      That’s a reasonable hypothesis. Or it could be a genuine question. Lots of interesting responses in any case, so whatever it was, it wasn’t a stupid question.

      • You are correct… not a stupid (I really do not use that word very often so it sounds weird) question at all. None the less, a question worth answering. So, overall a good question even if meant to be a set up for trolls.

        In reply to #19 by OHooligan:

        In reply to #18 by crookedshoes:

        I find the OP to be a loaded question. … I smell an ulterior motive.

        That’s a reasonable hypothesis. Or it could be a genuine question. Lots of interesting responses in any case, so whatever it was, it wasn’t a stupid question.

        • Could someone kindly explain to this new member the apparently widespread obsession with trolling (a word whose meaning as used here I had to (yes!) Google). I daresay I may one day make a clumsy point or ask an ill-thought out question and find it interpreted as trolling. Napoleon’s version of Ockham’s Razor when he suggested that explanations of incompetence trump those of conspiracy theory seems to me to be more useful and anyway, what’s the diff? As the other post seems to say, if it’s a good or provocative question, never mind the provenance, feel the width. Hey Ho.In reply to #21 by crookedshoes:*

          You are correct… not a stupid (I really do not use that word very often so it sounds weird) question at all. None the less, a question worth answering. So, overall a good question even if meant to be a set up for trolls.

          In reply to #19 by OHooligan:

          In reply to #18 by crookedshoes:

          I find th…

  8. it’s a question that many people have wondered but i suspect is given more importance than it deserves.

    i was recently told by a sibling that ther’es a big hoo-ha going on about someone writing a theses suggesting sexual reproduction is not very efficient therefore darwin was wrong. i ignored the comment as i suspect he was trying to get a rise out of me but firstly, this academic turned out to be a philosopher (move along nothing to learn here) and secondly was just regurgitating some ID mantra.

    in fact it may be less efficient but it works where it works, and you can always come back to the argument that 90% of the planets biomass is single-celled non-sexual, the “big questions” (sex, big brains, opposable thumbs etc) are only big if you fall into the catagory yourself, otherwise you’re talking about an anomily that found a niche, just like the long middle finger of the eye-eye, a curiosity to any observer, a fundamental mysery of the purpose of life to any eye-eye philosophers

    it’s no answer to the actual question, sorry!

    • In reply to #23 by SaganTheCat:

      it’s a question that many people have wondered but i suspect is given more importance than it deserves.

      i was recently told by a sibling that ther’es a big hoo-ha going on about someone writing a theses suggesting sexual reproduction is not very efficient therefore darwin was wrong. i ignored the c…

      Efficiency is a very useful word. Whenever it appears beyond the context of an engineering textbook it is one of the most efficient indicators of irrational thinking.

      It’s possibly the most efficient word in the English language for indicating the clumsy concept of ‘I don’t really understand this and I haven’t really thought it through but I’ll throw in some technical sounding words to obscure comprehension’. Though its use in this context the word seems to have recently evolved to become a slightly less efficient way of stating that something is somehow ‘good’, but without need to explain why. Similar to Cialdini’s explanation of how people readily comply with another’s statements and requests if they detect the presence of something that appears to be a reason in the request – even if it isn’t a real or meaningful reason. E.g. “Please let me cut in line because cats are blue” could work as effectively as any more tangible reason. The mind automatically tests for the presence of the reason, not the quality. This being the most efficient mental process for handling awkward social situations. By eliminating the psychological need for an associated explanation the word itself is therefore a more efficient explanation.

      In its original technical engineering sense its meaning is the very opposite of evolved life processes – which depend on diversity, redundancy, indirect, and wasteful metabolic pathways. So it would be most biologically efficient for living things not to bother. And a truly intelligent designer of living organisms would presumably strive for greatest efficiency. Possibly why they also didn’t bother. Instead leaving well enough alone. Consequently we can be confident that natural evolutionary processes were all that was available to produce life.

      A truly intelligent designer would also be so extremely efficient that they couldn’t exist compared to the output of their creation. So the combination of evidence of natural evolution, combined with evidence of the absence of an intelligent designer, is the only available proof of a highly efficient intelligent design.

  9. Hi,

    What a quite interesting question, but quite complex too ? It made me search on the internet too.
    I´ve found some stuff on the internet,and the author even quotes Dawkins (it´s brasilian Portuguese, but I guess there are page translators available, here´s a google translation of a piece of the article that I´ve found:

    “Germ and birth sex

    During evolution, the appearance of germ cells is regarded as the birth Sex. While other body cells (somatic) carry two pairs (one maternal copy, another paternal) of each gene is the genetic heritage of the individual germ cells pairs separate and each gamete will contain only one copy of each gene. Some copies have maternal origin, others will rise in the paternal lineage.
    The gametes containing half of the gene in somatic cells of an individual, or be fertilized by fecundarão germ cells containing half of the gene copies from another individual. Union, will result in a new living being whose genome (set of all genes) will consist of one copy of each gene: one coming from the parent, the other parent.
    Of course we can not say which of the two cell types, somatic or germ, is more important for the survival of the species. No reproduction without gametes and somatic cells did not exist there would be no body. From the point of view of the evolution of life on Earth, however, the only function of the body is to optimize the survival and function of the reproductive gametes.
    Richard Dawkins, an evolutionary biologist at Oxford, summarizes the previous thought in one sentence: “The chicken is the best way I found an egg to make another egg.

    article
    .

    Have you ever thought that a female alone could reproduce ?

    see:

    Parthenogenesis in Komodo dragons

  10. I am unable to answer this, but one point I need to make after a very quick scan of the responses is that ‘gender’ has NOTHING to do with biological or physical sex… it is no more than an accepted construct of generalised behaviours that are conceptually applied to the sexes.

    • In reply to #28 by jedda.lingmar.5:

      I am unable to answer this, but one point I need to make after a very quick scan of the responses is that ‘gender’ has NOTHING to do with biological or physical sex… it is no more than an accepted construct of generalised behaviours that are conceptually applied to the sexes.

      On most things I’m pretty far to the left but its exactly this kind of PC un-scientific rhetoric that makes me understand why some people look down on lefties. Gender absolutely does have a biological definition. Try taking a biology class without understanding the impact of gender roles, competition between males for females (and sometimes vice versa), etc. and you won’t get very far.

      I think what you mean is that gender roles are social constructs as well as biological and its possible to be born with physical qualities of a male and feel (or biologically in some ways to be) female and I completely agree. One clear thing about biological gender roles is that they are fluid and flexible and highly varied across and within species. But to say that gender has nothing to do with physical sex is as rational as the people who say that evolution is just a theory.

  11. Thank you for your response Red Dog, and yes the concept of gender was formulated based on the general natural behaviour of the sexes… my issue is that it is now accepted as nature and a real evolutionary fact when it is really no more than a generalised construct. I get what you mean when you say about it’s ‘fluidity.. but if it is such a scientific fact that can be applied to the sexes then there should be no flexibility… in fact, there should be no such thing as a person who feels that they do not fit into the ‘assigned’ roles if it is so correct. I know just how dangerous this concept is as a victim of it… I spent much of my life in emotional turmoil due to the fact that I did not fit the gender ‘feminine’ as a female of the species. I have since come to terms with this issue so all is good. You noted that I may have explained myself incorrectly.. and I agree. Sometimes I do find it difficult to find the right words.

    • In reply to #30 by jedda.lingmar.5:

      Thank you for your response Red Dog, and yes the concept of gender was formulated based on the general natural behaviour of the sexes… my issue is that it is now accepted as nature and a real evolutionary fact when it is really no more than a generalised construct. I get what you mean when you say…

      Sorry if my first comment was a bit harsh. Its sort of a pet peeve of mine because I think on most issues (gay rights, climate change, healthcare, etc) the left has so much science and reason on our side it bothers me, probably more than it should, when I see people I mostly agree with say things that IMO aren’t supported by science.

      If you are interested in the science behinds some of this I would really recommend the book The Blank Slate by Steven Pinker. For me that book was kind of a revelation. He really clarifies some of the science behind issues of nature vs. nurture and sexual roles and identity. One of the things I really liked about the book is Pinker is very clear that he is not using it as a support for right wing ideas and he makes a great distinction between what science says is true and what humans think ought to be true.

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