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Thread: Male and Female Evolution ???

  1. #1 Male and Female Evolution ??? 
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    For a project, my teacher assigned a writing assignment where we are supposed to explain how Males and Females came to exist separately, but mess perfect with one another.

    I think my teacher may be a pro religion, but I don't know for sure. But I am having a hard time finding answers to the questions that we are supposed to use in our paper.

    Did males come from females? Did males and females sprout up at exactly the same time? Males and females are so different so how did they evolve to match perfectly? If there wasn't both male and female at exactly the same time, to evolve at the same time, then the whole process dies in one generation? etc. etc.

    I was reading something about how hermaphrodites prove Darwinian Evolution, but I don't really get this and don't know if I should use this in my paper.

    Can someone help me on this? I am not necessarily trying to prove my teacher wrong, but I want to have some solid facts and science. I don't want a bad grade just for having different beliefs. But if I don't make a strong argument that might happen, I don't know.

    Any input, articles, links etc. would be helpful. Thanks


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  3. #2  
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    I think you're searching for the origin of sexual reproduction, which traces back to single celled organisms. I'm sorry to report it unsolved. If your teacher knows this, the assignment is a set-up isn't it?


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  4. #3  
    Forum Cosmic Wizard i_feel_tiredsleepy's Avatar
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    There are a lot of hypotheses about the origin of sexual reproduction (which precedes the evolution of single gender organisms). Hermaphroditic plants and animals came well before sexually dimorphic ones. Reviewing the wiki article is a good start to find ideas for searching more into the subject.

    As to the second part of your teacher's question. Once genders exist it is easy to see why selection would favour the individuals best able to reproduce sexually, thus there is selective pressure that promotes the ''perfect'' fit. I would suggest reading up on sexual selection. The use of the word perfect brings into question the teacher's qualifications in biology.
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    Non-sexual reproduction is still by far the major form of reproduction among living things. Sexual reproduction is only prevalent among the visible veneer of macro life. Also, not even all vertebrates use sexual reproduction. some, like the whiptail lizzard are all female and give birth without a male sperm donor. Many arthropods (like aphids) can reproduce either via sexual or asexual means. Some life forms among fishes and anphibian scan change sex depending on the variables present.

    Within our own bodies there are abot 750 types of bacteria just in our gut...all just dividing happily without a partner.
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    So are their maps of how male and female humans came about?

    Example:

    Hermaphroditic organisms
    Hermaphroditic organisms mutate
    One organism mutates with more male traits, one mutates with more female traits
    Base on environment, organisms mutate into vertebrates
    Male and female vertebrates - great apes
    Great apes evolve into humans


    Please forgive my vagueness and/or ignorance. But could someone help me break down a more in depth map on how male and female humans came to be? Thanks very much.
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  7. #6  
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    These are some educational videos that may get you pointed in the right direction.

    Is Multi-Gender Sex Better?
    The Joy of Sex (ual Reproduction)
    The Evolution of Sex
    The Origin of Sexual Reproduction
    Artist for Red Oasis.
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  8. #7  
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    Sexual reproduction is a mechanism for mixing and mingling genes. Non sexual reproduction results in offspring that are genetically identical to the parent. Most of the time this is very effective, and makes lots of offspring.

    However, the environment in which all living things exist is not constant. It changes. If all offspring remain identical to some ancestor, then they are not equipped to cope with a changing environment. Thus, organisms mix and mingle genes to make sure that the offspring are NOT identical to the parent. In this way, when the environment changes, some offspring will be able to survive.

    For example : all multi-cellular living things are subject to attack by disease causing bacteria and viruses. The bacteria and viruses change due to mutation. If an organism is resistant to a virus, for example, and that virus changes, then the organism has to change also - or else it will die out due to the virus disease. Sexual reproduction, with its mixing of genes, permits offspring to change, so that some will survive the virus attack.

    The very first sexual life would not have had male and female forms. All would have been the same. Indeed, some simple organisms today are the same - no male and female. However, they join to mix their genes and make offspring that are genetically different.

    Once organism evolved more complexity, and became larger, they would evolve specialised reproductive organs. These first complex plants and animals lived in the ocean, and released their sex cells into ocean water to meet up and join. To do this required vast numbers of cells. However, there is advantage in making the sex cells big enough to contain a food reserve for the new offspring to live on until it grows enough to feed itself. But why make both cells that join so big? It is actually more efficient to make a small number of large cells containing foodstuffs (female sex cells), and a large number of smaller cells without stored food to join with them (male).

    And so it goes....
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    So basically single celled organisms mutated and evolved, eventually creating males and females. More genders could have been created, but since more that two would be problematic, male and female became dominant. Then over time those male and female organisms became more complex and evolved and mutated into various plants, mammals and reptiles?

    So as a map, you could do something like this below?

    Single celled asexual organisms
    Mutated and evolved single celled organisms to multi-celled, multi-gendered
    Male, female and hermaphroditic multi-celled organisms
    Evolution of plants, reptiles and mammals with two genders
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  10. #9  
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    Non-sexual reproduction would probably end up like when you use a xerox copier to make a copy of a copy of a copy, and the original image degrades. Some mechanism is needed to ensure that positive changes occur just as frequently as negative ones, or at least ensure that the negative ones don't ever occur/survive with enough frequency to overrun.

    With sexual reproduction, each offspring can be radically different from each other, but in a way where the combination of traits is still mostly based on something nature has proven effective (the parents). It's a way to make "hedged" bets, where there's less risk of flukes in the environment having sway over the long run traits of that environment.
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    juantonwan, you're getting a lot of good advice and references to go check up. Go review this information we've given you, and see if you think your "map" is accurate. Also keep in mind that many of these things are hypotheses, not yet fully proven. It is important that you don't present these things as facts but as possibilities.

    One hypothesis of the evolution of sex actually starts out with single celled organisms. Let's say you have a variety of single celled organisms, that can bump into each other and exchange DNA (effectively have sex) before they replicate. Some are very small, some are medium sized, some are very large. If you're very small, you're fast - you can zip around, bump into lots of other cells, giving them some of your DNA before moving on to the next one. If you're very big, you can't move quickly but once you've exchanged DNA you can split into new daughter cells several times without having to take in any more energy or resources than you already have. If you're a middle sized cell, you lose out to both. You can't bump into as many other cells as the small fast guys and you can't make as many daughter cells as the large slow guys. Thus there is a divergent selection pressure to be one extreme or the other, instead of everybody being the same.
    Man can will nothing unless he has first understood that he must count on no one but himself; that he is alone, abandoned on earth in the midst of his infinite responsibilities, without help, with no other aim than the one he sets himself, with no other destiny than the one he forges for himself on this earth.
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    Forum Cosmic Wizard SkinWalker's Avatar
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    You might also check this link: The Evolution of Sex

    I haven't read it, but this book came up on google books as a recommended for me a while back. It seems to have quite a few pages you can read in "Preview" mode, so I think you can get some valuable info and probably some additional citations and sources to read in the footnotes/endnotes.
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    From:
    http://www.space.com/scienceastronom...ex_010710.html

    "Roughly 1 billion years after the first organisms romped in the hay, the
    origin of sex remains one of biology's greatest mysteries. Scientists can't
    say exactly why we do it, or what triggered those initial terrestrial
    flirtations. Before sex, life seemed to manage fine by employing asexual
    reproduction -- the cloning of offspring without the help of a partner.

    Now a new study out of Caltech and NASA's Jet Propulsion Laboratory has used
    digital organisms to simulate life before sex and yielded a possible
    mechanism for instigating Earth's first courtship.

    Intimacy never sounded so stressful.

    Comet or asteroid impacts could have stressed asexual organisms enough to
    send them down the path of sexual reproduction after forcing a flurry of
    genetic mutations, the study shows. Heavy doses of radiation might also have
    done the trick."
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    Prokaryote 'sex' is very simple. These bacteria and Archaeans have a large chromosome running through the cell, which contains most of the DNA. However, they also have tiny circular molecules of DNA drifting through the insides of their cells. These tiny rings of DNA are what is exchanged in bacterial 'sex'. The main mass of DNA remains unchanged.

    Eukaryotes have much larger cells, and include what is almost certainly symbiotic bacteria inside their cells (called mitochondria, and chloroplasts in green plants). The mitochondria carry out chemical respiration, releasing energy, and the chloroplasts contain chlorophyll to carry out photosynthesis.

    It appears that the first true sex occurred at about the same time as the first eukaryote cells appeared with their symbiotic passengers. There is a theory that this massive change is what caused sexual reproduction to become necessary. In other words, accepting useful bacteria into the cell, while it conferred huge benefits, also carries the risk of accepting bacteria that have been massively harmful.

    To survive the transition required rapid adaptation. This adaptation requires much greater genetic diversity, that comes from sexual reproduction. If this theory is correct, the first true sexual reproduction evolved alongside the evolution of the eukaryote cell in symbiotic union with mitochondrial and chloroplast bacteria.

    This theory was written up in detail in a recent issue of New Scientist.
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  15. #14  
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    Bacterial conjugation isn't exactly sexual reproduction, although it probably has something to do with the evolution of sex. Some bacterial plasmids are more analogous to genetic parasites than they are to sexual reproduction.

    I'm not immediately convinced by the idea that endosymbiosis induced sexual reproduction. That being said, the larger size and longer generation period of eukaryotes would seem to favour sexual reproduction as a means of generating diversity with fewer generations. As we see numerous asexual eukaryotes amongst the oldest genera, if you look at a phylogenetic tree it seems to me that sexual reproduction had to appear sometime before the divergence of plants from animals, thus sometime before the integration of the chloroplast. The groups that come after that: alga, plants, fungi, slime molds, and animals, all employ sexual reproduction. Before that it seems to become quite complicated as there is no guarantee sexual reproduction hasn't evolved independently multiple times and these groups are more difficult to define.
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    Iíve been pondering a theory that predation may have played a significant role in the evolution of the sexes. The earliest form of reproduction probably involved little more than cellular division (mitosis), among single cell organisms, when an organism absorbed sufficient nutrients. At this stage of early primitive life, there was probably no sexual distinction among existing organisms. So long as their primordial sea environment held sufficient nutrients, these ancient organisms could survive and multiply. We owe the oxygenation of early earth to such simple organisms. With predation, these primitive organisms would have had to rely on the genetic material of other single cell organisms to survive and reproduce. We know predation existed among the complex species of the Cambrian Era and there is a believe that predation among the soft-bodied creatures of the Vendian period may have influenced Vendian evolution into the armored and fierce creatures of the Cambrian Era.

    Early, non-sexualized organisms or creatures may have relied on predation and, by extension, the genetic material of like-organisms to achieve mitosis when the size of their colonies outstripped the resources of their environment. We know from existing species, that some will surrender an appendage or spew part of their gut to escape predation. It seems plausible that the smaller and weaker among ancient like-species evolved the ability to surrender there genetic material to escape predation. Over time, this could have produced a division among like-organisms where the one that reproduced was more robust and aggressive. This likely would have led to a female dominant species line. Perhaps this offers some insight into why the female is often more robust and dominant than the male among some existing primitive species (e.g., ant, bee and wasp colonies, arachnid and mantis species). This may not be a well formed theory, but it is one that has piqued my interest for a while.
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    How important is the origin of sex, to evolution theory?? I would think it is pretty important, but I keep getting different answers and hearing different theories? Are there any hard facts I can use, or do I just have to pick the best hypothesis?

    Why did the earliest asexual organisms feel the need to bump into each other (exchange information)? Why can't asexual, either multi or single celled, organisms mutate and evolve just as sexual, multi-gender organisms supposedly did? In fact, wouldn't asexual organisms reproduce faster, allowing them to evolve and mutate if they were in a harsh or changing environment?
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    Quote Originally Posted by juantonwan
    How important is the origin of sex, to evolution theory?? I would think it is pretty important, but I keep getting different answers and hearing different theories? Are there any hard facts I can use, or do I just have to pick the best hypothesis?
    As I've said already, juantonwan, there is no definitive answer. This is an active area of research and there are several hypotheses. For a complete paper I would tell you to describe and list the evidence for all of the ones you've found. Or if that's too much effort review the evidence yourself and decide which hypothesis makes the most sense to you.

    Why did the earliest asexual organisms feel the need to bump into each other (exchange information)? Why can't asexual, either multi or single celled, organisms mutate and evolve just as sexual, multi-gender organisms supposedly did? In fact, wouldn't asexual organisms reproduce faster, allowing them to evolve and mutate if they were in a harsh or changing environment?
    The main benefit of sex is that it creates variation more quickly by exchanging and recombining genes. If you live in an environment that has unpredictable dangers, having offspring with more variety gives you a better chance that some of your offspring will get the right combination that will allow them to survive and reproduce. Mutation happens at a relatively fixed rate and if it's just not fast enough, sex can add the extra edge.
    Man can will nothing unless he has first understood that he must count on no one but himself; that he is alone, abandoned on earth in the midst of his infinite responsibilities, without help, with no other aim than the one he sets himself, with no other destiny than the one he forges for himself on this earth.
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    Quote Originally Posted by paralith
    Quote Originally Posted by juantonwan
    How important is the origin of sex, to evolution theory?? I would think it is pretty important, but I keep getting different answers and hearing different theories? Are there any hard facts I can use, or do I just have to pick the best hypothesis?
    As I've said already, juantonwan, there is no definitive answer. This is an active area of research and there are several hypotheses. For a complete paper I would tell you to describe and list the evidence for all of the ones you've found. Or if that's too much effort review the evidence yourself and decide which hypothesis makes the most sense to you.

    Why did the earliest asexual organisms feel the need to bump into each other (exchange information)? Why can't asexual, either multi or single celled, organisms mutate and evolve just as sexual, multi-gender organisms supposedly did? In fact, wouldn't asexual organisms reproduce faster, allowing them to evolve and mutate if they were in a harsh or changing environment?
    The main benefit of sex is that it creates variation more quickly by exchanging and recombining genes. If you live in an environment that has unpredictable dangers, having offspring with more variety gives you a better chance that some of your offspring will get the right combination that will allow them to survive and reproduce. Mutation happens at a relatively fixed rate and if it's just not fast enough, sex can add the extra edge.


    Thank you for your reply. I appreciate all your help.


    So the theory is that the Earth was very hostile, unpredictable and dangerous early on, and it was too much for asexual organisms to survive? So instead of continuing to reproduce asexually, they started exchanging DNA to reproduce organisms that had mixed genes to better adapt and evolve?

    But if the asexual organisms couldn't evolve and survive the harsh environment, why would exchanging DNA with similar asexual organisms that can't evolve or survive the harsh environment, make a difference and/or allow them to change and evolve.
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  20. #19  
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    Quote Originally Posted by juantonwan
    So the theory is that the Earth was very hostile, unpredictable and dangerous early on, and it was too much for asexual organisms to survive? So instead of continuing to reproduce asexually, they started exchanging DNA to reproduce organisms that had mixed genes to better adapt and evolve?

    But if the asexual organisms couldn't evolve and survive the harsh environment, why would exchanging DNA with similar asexual organisms that can't evolve or survive the harsh environment, make a difference and/or allow them to change and evolve.
    Well, obviously not the entirety of the earth had these specific conditions, because there are plenty of asexually reproducing organisms still around today. There is a lot of variety on this planet; in some places the conditions are such that the extra genetic variation brought on by sex is a big advantage; in other places, it's a disadvantage, and the asexually reproducing organisms did better than the sexually reproducing ones, allowing them to persist until today.
    Man can will nothing unless he has first understood that he must count on no one but himself; that he is alone, abandoned on earth in the midst of his infinite responsibilities, without help, with no other aim than the one he sets himself, with no other destiny than the one he forges for himself on this earth.
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  21. #20  
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    Quote Originally Posted by paralith
    [
    Why did the earliest asexual organisms feel the need to bump into each other (exchange information)? Why can't asexual, either multi or single celled, organisms mutate and evolve just as sexual, multi-gender organisms supposedly did? In fact, wouldn't asexual organisms reproduce faster, allowing them to evolve and mutate if they were in a harsh or changing environment?
    The main benefit of sex is that it creates variation more quickly by exchanging and recombining genes. If you live in an environment that has unpredictable dangers, having offspring with more variety gives you a better chance that some of your offspring will get the right combination that will allow them to survive and reproduce. Mutation happens at a relatively fixed rate and if it's just not fast enough, sex can add the extra edge.
    Yeah, and it remains just as true in an ordinary environment too. The ability to mutate rapidly allows you to be the first to fill new niches when they open up. Usually, once a niche is filled, all real competition for it stops, so the fastest mutating organism is sometimes the only one that gets any benefit at all.

    It's kind of like nature issues patents to new genetic inventions. If you're the first organism that can operate in a new environment, then you get to spend several generations totally competition-free while the other potential competitors are waiting to catch up. During that time, you'll have a population explosion, because nobody is competing with you for your food supply, and by the time the next organism catches up, that niche is already crammed full of your progeny.

    In some ways, this is the #1 advantage of human beings. We can change the ideas in our heads without waiting for instincts to evolve. Once we have an idea, we just spread it around with our communication skills so it only takes a generation or two. That makes us faster adapters than any other species on Earth.
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  22. #21  
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    Quote Originally Posted by kojax
    Yeah, and it remains just as true in an ordinary environment too. The ability to mutate rapidly allows you to be the first to fill new niches when they open up. Usually, once a niche is filled, all real competition for it stops, so the fastest mutating organism is sometimes the only one that gets any benefit at all.

    It's kind of like nature issues patents to new genetic inventions. If you're the first organism that can operate in a new environment, then you get to spend several generations totally competition-free while the other potential competitors are waiting to catch up. During that time, you'll have a population explosion, because nobody is competing with you for your food supply, and by the time the next organism catches up, that niche is already crammed full of your progeny.
    Well, it's definitely true that if you find a way to take advantage of one particular niche before anyone else does, you can have a population explosion into that niche. However, just because you're the first one there doesn't mean competition stops or that others can't muscle in on your territory. If another organism evolves traits that take even better advantage of that niche, or perhaps even preys on you, then you could be wiped out just as quickly as you spread.

    A lot of biologist like to use the metaphor of the Red Queen. In Alice in Wonderland, Alice and the Queen of Hearts partake in a race where they're running and running, and Alice comments that it seems like they're staying in exactly the same place, and the Queen replies that sometimes you have to race just to stay in the same place. There will always be organisms that are competing with you for resources, and if they can bump you out of your niche and take it, they will. So you have to evolve defenses against them just to stay where you are.

    In some ways, this is the #1 advantage of human beings. We can change the ideas in our heads without waiting for instincts to evolve. Once we have an idea, we just spread it around with our communication skills so it only takes a generation or two. That makes us faster adapters than any other species on Earth.
    And it makes us notoriously good at taking over whole areas and modifying them to fit our own needs, effectively destroying the niches previously occupied by other animals.
    Man can will nothing unless he has first understood that he must count on no one but himself; that he is alone, abandoned on earth in the midst of his infinite responsibilities, without help, with no other aim than the one he sets himself, with no other destiny than the one he forges for himself on this earth.
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    But it is not always constant betterment is it? There are things that can be detrimental correct? And if there are sometimes they aren't fixed or compensated for.

    For example, today many humans smoke cigarettes. Lump in alcohol, drugs etc. They know it is bad and it causes many death, but it remains at large. This cannot be beneficial in anyway.

    So there had to be "cigarettes" for early organisms. So not only are they battling against environmental changes, they are battling against themselves.

    So being asexual, battling the environment, battling themselves; how do they evolve and improve before they harm themselves, and why would mixing with similar asexual organisms make a difference? - Would they have to exchange DNA with significantly different organisms? But how does this work? For example, humans can reproduce with donkeys. So not only are they early single celled organisms battling, but they have to find organisms they are actually compatible to exchange DNA with.

    - I guess, like it has been stated, this area of science is not clear and being studied in depth. So we have to choose just choose they best hypothesis and go with it.
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    juantonwan

    Sexual reproduction, as previously stated allows for more variability. As with both kinds of reproduction, most offspring perish. For example : a fish may, through sexual reproduction, create literally millions of offspring over its lifetime, and on average only one will survive to reproduce in turn.

    Since sexual reproduction means all these millions are genetically different from each other, the ones that are most likely to survive are those that are different in such a way as to make them better adapted to their local environment. By weeding out the variations that are maladapted, the population changes rapidly over not too many generations, to form a new type that is adapted to the environment. Hence sexual reproduction permits the species to survive, though not most individuals.

    A possibility that was discussed in the New Scientist article I referred to before, is that asexual reproduction may have re-evolved later from sexually reproducing ancestors. If the environment is stable, asexual reproduction is better, since it requires only one individual, which can produce many more offspring. For example : fungi reproduce asexually to release billions of spores, each capable of growing into a new adult.

    Sexual reproduction has the advantage only in a changing environment, when rapid adaptation from greater genetic variability allows the species to survive those changing conditions.

    In fact, many organisms use both methods. Sexual tends to be used when conditions are harsh. Asexual when everything is going well. Many fungi do this.
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    I appreciate everyone's input!

    So the theory is that the Earth was very hostile, unpredictable and dangerous early on, and it was too much for asexual organisms to survive? So instead of continuing to reproduce asexually, they started exchanging DNA to reproduce organisms that had mixed genes to better adapt and evolve? But if the asexual organisms couldn't evolve and survive the harsh environment, why would exchanging DNA with similar asexual organisms that can't evolve or survive the harsh environment, make a difference and/or allow them to change and evolve?

    So now do we have to look at the origin of multicellular organisms? It seems that single celled organism would have had to evolve into multicellular organisms, prior to the evolution of sex.
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    Quote Originally Posted by juantonwan
    I appreciate everyone's input!
    I'm glad you do, but I have to admit it's getting a little frustrating because you keep asking the same questions to which we have already given you answers.

    So the theory is that the Earth was very hostile, unpredictable and dangerous early on, and it was too much for asexual organisms to survive? So instead of continuing to reproduce asexually, they started exchanging DNA to reproduce organisms that had mixed genes to better adapt and evolve?
    This was only true for some organisms in some environments. It cannot be true for all organisms because we have aesexual reproducers alive today, as I've already mentioned.

    But if the asexual organisms couldn't evolve and survive the harsh environment, why would exchanging DNA with similar asexual organisms that can't evolve or survive the harsh environment, make a difference and/or allow them to change and evolve?
    Because they are not all clones of each other, juantonwan. Let's consider different lineages of unicelleular organisms instead of individuals. As a simple example, let's say you have organism A, organism B, and organism C. They are all slightly different from each other. Now, they can reproduce aesexually and just make copies of themselves (creating lineages of A's, B's, and C's) or they can swap genes between them to create more variation (so you have mixed AB, AC, and BC lineages too.) This creates variation faster than creating variation by mutation alone, as has already been said.

    So now do we have to look at the origin of multicellular organisms? It seems that single celled organism would have had to evolve into multicellular organisms, prior to the evolution of sex.
    Not necessarily no. Again, as has already been discussed, many hypotheses of sex have it beginning with unicellular life.

    Juantonwan, once again I urge you to carefully and thoroughly read the sources provided to you and posts written in this thread. All the information you need will be there. At this point you need to start doing your own work reading the information given you and bringing the main ideas together in a paper. As the Biology moderator I am only going to allow this thread to continue for a little while longer if you keep asking us the same questions.
    Man can will nothing unless he has first understood that he must count on no one but himself; that he is alone, abandoned on earth in the midst of his infinite responsibilities, without help, with no other aim than the one he sets himself, with no other destiny than the one he forges for himself on this earth.
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    Quote Originally Posted by kojax
    It would make sense if something like that happens with animal evolution sometimes as well. I bet the first organism to enter a niche probably starts getting complacent after a while, in a sense. If you're perfectly evolved for your environment, there's no reason you'd keep on mutating, or not very much.
    Well, first of all mutation happens every time cells divide, so no animals just stops mutating or slows down mutation in response to changing competitive pressure. Within a given niche, the organisms there are always being selected on, so that those mutations which pop up which may reduce their fitness in that niche are removed, and those mutations which pop up which may actually increase their fitness in that niche are kept. Thus even without competitors, no species just chills out. Second of all, no species exists in a bubble; there will always be other organisms around, and like I already said, as soon as one is capable of muscling you out of your niche, it probably will.


    That makes sense, so long as we add in a condition where the first person to reach certain points in the race gets a special reward, like a drink of water or something, so it's possible to have a sort of cascading victory.
    Of course you get a "reward," you get increased reproductive success. But the point of the Red Queen race is not in getting to that place, it's in staying there, it's in keeping that "reward" all to yourself. There will always be others trying to get theirs too.

    Imagine how the NBA would look if there were no official draft, and the most successful teams could always recruit the best new blood. After a while all the good players would be on a few key teams, and then maybe it would go another step and there'd only be one team worth watching. But.... after a while I somehow think another team might surface to compete with them. If only because of the complacency factor.
    Human behavior is not a good analogy for evolutionary processes. The way we think and the goals we have in our conscious minds are not the same as what drives evolution.
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  28. #27  
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    Could sexual reproduction originate with viruses (or vise versa)?
    A pong by any other name is still a pong. -williampinn
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    You also have to be careful how you explain the process:

    So instead of continuing to reproduce asexually, they started exchanging DNA to reproduce organisms that had mixed genes to better adapt and evolve?
    This makes it sound like there was a general meeting where the asexual single cells got together, discussed the problem, and then decided they would invent a new method called 'sex'.
    Obviously this is a ridiculous example, but I use the extreme to illustrate the point that when sex appeared, it was due to variable chance; much like a predacious animal cell phaging the first primitive Mitochondria and BAM! Life on Earth changes forevermore! Who could have seen THAT one coming?!

    Obviously asexual reproduction had fared perfectly well up until that point. When sex appeared by chance, it would have obviously created such variation in offspring so fast, that it was an explosive (heh heh) population event.
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  30. #29  
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    Quote Originally Posted by the other kojax
    Quote Originally Posted by kojax
    It would make sense if something like that happens with animal evolution sometimes as well. I bet the first organism to enter a niche probably starts getting complacent after a while, in a sense. If you're perfectly evolved for your environment, there's no reason you'd keep on mutating, or not very much.
    Well, first of all mutation happens every time cells divide, so no animals just stops mutating or slows down mutation in response to changing competitive pressure. Within a given niche, the organisms there are always being selected on, so that those mutations which pop up which may reduce their fitness in that niche are removed, and those mutations which pop up which may actually increase their fitness in that niche are kept. Thus even without competitors, no species just chills out. Second of all, no species exists in a bubble; there will always be other organisms around, and like I already said, as soon as one is capable of muscling you out of your niche, it probably will.
    What I'm getting at is that, without selective pressure, there's no direction to an organism's mutation process. With no direction, you're basically marching around in circles, which would have a similar effect to staying put.

    I guess what really happens is that the incumbent organism has had more time to refine it's level of adaptation to the niche it's filling, by making small changes here and there, but the newcomer might have a spectacular new strategy that the incumbent organism has never even come close to.

    That makes sense, so long as we add in a condition where the first person to reach certain points in the race gets a special reward, like a drink of water or something, so it's possible to have a sort of cascading victory.
    Of course you get a "reward," you get increased reproductive success. But the point of the Red Queen race is not in getting to that place, it's in staying there, it's in keeping that "reward" all to yourself. There will always be others trying to get theirs too.
    So sexual reproduction would be like growing a longer pair of legs. The speed you can run at has permanently increased, so if the others couldn't catch you beforehand, they certainly won't be catching you afterward. (Until they too reach the point of growing a longer pair of legs to run with. )

    Humanity's advantage then is that we gained another increase in the length of our legs by evolving abstract communication of ideas. Instead of instincts that increase in effectiveness with our genes, we have knowledge sets that increase with our level of education, and the growth of the effectiveness of our education over time, or scientific understanding, is many orders of magnitude faster than the growth in effectiveness of an animal's instincts.
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  31. #30  
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    Quote Originally Posted by kojax
    What I'm getting at is that, without selective pressure, there's no direction to an organism's mutation process. With no direction, you're basically marching around in circles, which would have a similar effect to staying put.
    Yes, you've got the right idea - just remember that mutations never have a direction. They're always random.

    I guess what really happens is that the incumbent organism has had more time to refine it's level of adaptation to the niche it's filling, by making small changes here and there, but the newcomer might have a spectacular new strategy that the incumbent organism has never even come close to.
    Yes, that's very possible.

    So sexual reproduction would be like growing a longer pair of legs. The speed you can run at has permanently increased, so if the others couldn't catch you beforehand, they certainly won't be catching you afterward. (Until they too reach the point of growing a longer pair of legs to run with. )
    lol, that's taking the metaphor in a direction I've never seen before, but sure. A good example is evolutionary "arms races" between predators and prey. The deer get faster to out run the cheetahs, the cheetahs get faster to out run the deer, and back and forth it goes until you've got two of the fastest land runners in the world. The "same place" the deer are trying to stay in is the place where they can mostly escape the cheetahs; the "same place" the cheetahs are trying to stay in is the place where they can catch enough deer to feed themselves well.
    Man can will nothing unless he has first understood that he must count on no one but himself; that he is alone, abandoned on earth in the midst of his infinite responsibilities, without help, with no other aim than the one he sets himself, with no other destiny than the one he forges for himself on this earth.
    ~Jean-Paul Sartre
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