Natural selection past the reproductive age

Discussion in 'Biology & Genetics' started by spuriousmonkey, May 17, 2004.

  1. John Connellan Valued Senior Member

    Messages:
    3,636
    Thats actually right Paul and it does lend credibility to the 'emergence theory'.
     
  2. Google AdSense Guest Advertisement



    to hide all adverts.
  3. BigBlueHead Great Tealnoggin! Registered Senior Member

    Messages:
    1,996
    Danniel, you mentat, think harder!

    As an example of an emergent property, let us think of the human behaviour of MAKING SHOES. We make shoes; nearly every culture has invented or adopted footwear during the development of humankind.

    There's no genes that code for shoemaking; we could not make a "mutant" human who did not have a shoemaking propensity without also affecting many other aspects of their behaviour.

    However, shoemaking has a selective advantage - it protects your feet from blisters, scorpions and thorny plants. People with shoes are more likely to live long enough to have children than people without shoes, in an environment where these hazards exist.

    So, the genetic material of those people who have shoes is more likely to be passed on than the genetic material of people with no shoes. And - get this - humans can teach their offspring to make shoes! So, the selective advantage continues on through the line.

    Does this make sense?
     
  4. Google AdSense Guest Advertisement



    to hide all adverts.
  5. John Connellan Valued Senior Member

    Messages:
    3,636
    U could almost say genes are working (and being selected for) synergistically when put together (Oh no, I'm gonna get blasted for saying that now

    Please Register or Log in to view the hidden image!

    )

    Stand back now .....Paul....BigBlue....

    Please Register or Log in to view the hidden image!

     
  6. Google AdSense Guest Advertisement



    to hide all adverts.
  7. BigBlueHead Great Tealnoggin! Registered Senior Member

    Messages:
    1,996
    Yes, sort of like hydrogen works synergistically when put together to make the sun, and hence every living thing on our planet. All hail hydrogen, progenitor of life! Things just wouldn't be the same without it. Forget about those other loser elements, they'd be nothing without hydrogen! Why, they're made out of hydrogen - that's all you need to know.

    So order now! Our trained operators are standing by.
     
  8. Buckaroo Banzai Mentat Registered Senior Member

    Messages:
    332
    I just hope Spurious Monkey don't mind we completely changing his topic and barely touching it... anyway I have a tiny thing about that I'll post later...

    I can see that one gene-one trait would be necessary if we're suposing that all the characteristics of living things were "absolute" adaptations, completely ignoring the co-dependence of the parts, a sort of ultra-adaptionism by gene-selection extremism

    Please Register or Log in to view the hidden image!

    . But I thought it is said "gene" much in the sense of Mendel's "factors" (or at least that's how I consider it), more or less the conjoint of genes responsible to a trait, whatever they are; in this sense I still can't see why it would not work.

    How do non-gene-selectionist explain behaviors related with relativeness? Genes count for that, or the genetic proximity is just incidental? Because I think that although the same behavior to a relative can occur with non-relatives, it only will occur, mostly, if we "cheat" their instincts to the one individual see the other as if the other was a relative. Also I do not understand agressive behavior against non-relatives, if potentially they're just equal to a relative, if we consider only individual phenotype. A example, lions and lionesses kill the offspring of others if they're in their territory, but why do not addopt them instead? Would not they have just the same individual effect of related offspring, and plus, without the expenses of raising them to the actual age? One point could be that this offspring individuals would be just cost more expense, thus competing with the offspring they already have. But again, this behavior of favoring relatives in detriment of non-relatives with the same individual potential claims to a genetic explanation; also, often some individuals of the offspring die for a reason or another, such as hyenas or african buffalos...

    ...don't think I'm just being disagreeable, I really like the topic, and that's the way I see it... to me is totally odd to try to see this sort of things in a non-genetic way... but I didn't read the pointed references yet....
     
  9. John Connellan Valued Senior Member

    Messages:
    3,636
    I don't think thats what they're saying. There is an indirect selection of genes whenever there is a selection of the carrier that bears them so consider 2 phenotypes - one who cares for every animal and one who cares for only the related animals. Which phenotypes are going to spread in the population? The ones, of course, which have genes that code for caring for reltives (i.e. more of the same genes!!!).

    It would be costly for the individual to do so.

    U have to keep in mind that the only lions in the population now have genes which allow them to recognise relatives and care for them ONLY. I believe genes control almost all our behaviour and that is another one. There simply could not be a significant number of genes allowing for caring for non-relatives!

    Im sure Paul and BigBlue are not abandoning the idea of genes altogether (in favour of individuals!). At least I hope not

    Please Register or Log in to view the hidden image!

    Please Register or Log in to view the hidden image!

     
  10. Buckaroo Banzai Mentat Registered Senior Member

    Messages:
    332
    I was going to post it yesterday, right before the last post, but I lost my connection:


    heh

    Please Register or Log in to view the hidden image!





    Yes, or at least some, since shoes are a cultural phenotype, rather than genetic... you're talking now about meme-selectionism!

    Please Register or Log in to view the hidden image!



    Anyway, again, I think this would be a reason against gene-selectionism only if were stated (and at least as I think, it's not implied) that there is a "absolute adaptationism". Despite of the fact of the nonexistence of a gene directly involved in shoemaking, there are many genes that make us capable of doing this, among many other things. If we regress enough in time when human culture wasn't what it is today, an extra-genetic adaptation capable of making even sterile individuals be selected, there were many sets of genes that would affect the capacity of make shoes and many others significantly; since the basis - all the responsible genes for a body capable of doing it, including a brain capable of controling this body properly, to genes that deal with minor abilities, such as a certain degree of agressiveness/self-control/patience, capacity of attentional focus, motor coordination, sequential memory, etc. Although some of these capabilities can be exercised by training, there also the natural-born tendences, and natural-born inabilities, I guess. Genes that led to extreme deviations from any of these capabilities, are certainly regulated by natural selection; unadequate degrees of deviation are also vulnerable, but not that much.

    ...now occurred to me that this may had been a extremely exaggerated example, like pointing leaf-mimic insects and leafs as a example of how phenotypical convergency do not led necessarily to genetic convergence... if was that... I'd ask for a more specifc example if you don't mind....
     
  11. Buckaroo Banzai Mentat Registered Senior Member

    Messages:
    332
    So again I'm really not understanding what's the difference. I thought that genes would be barely "tangible"... phenotypes that would not distinguish relativeness to their behavior... behavior would discern only wether individuals are of the same species or not (what is a great scale of genetic difference anyway), the sex and only few general things like these.



    But yet that would be cheaper than raise new offspring. They need to have offspring anyway, and I think that disregarding genes, the relativeness of this offspring would be irrelevant, as long as they're of the same species. If some individuals of their own offspring is killed by another species (and I guess that allways happen), stealing one found lonely unwatched by their mother would be a smart economy. And, suposing that there are benefits by having offspring -as more individuals, not more of the same genes - also they could steal even if they had not lost anyone yet (they probably will lost one in the future anyway), as long as they do not steal too many individuals at the point of creating overpopulated prides, but that would not happen anyway, because all the prides would be expected to do that every now and then, so it would be equilibrated.


    Yeah, I agree, but I don't see a reason to that occur if genes aren't a extremely relevant "target", baggage, unit or whatever of selection, at the point that again I see no difference between what I thought before. Maybe we're both sides talking about nonextant types of selection some sort of "ultra geneticism" and "ultra phenotypicism"..

    Please Register or Log in to view the hidden image!





    I think the same ...
     
    Last edited: May 27, 2004
  12. Buckaroo Banzai Mentat Registered Senior Member

    Messages:
    332
    now, back to the original topic a little bit - would that be considered off topic, or back in topic in the actual situation?

    I've seen in a Discovery Channel documentary that lionesses killed the offspring of another female that was in their territory. I do not know if those female "watchers", or some of the females in a pride had passed the reproductive age. At least can be, since that prides full the requirements to the "grandmother theory", I guess, being social and related... I guess I've heard somewhere that older females use to take care of the offpring while younger hunt, but I do not know if those older females had past the reproductive age....
     
    Last edited: May 28, 2004
  13. BigBlueHead Great Tealnoggin! Registered Senior Member

    Messages:
    1,996
    All right... I'll use an example from an animal behaviour lecture I attended once, having to do with what is known as stereotyped behaviour.

    Many human cultures have developed a tool known as the spear, a throwing weapon used for hunting. The spear provides us with a unique chance to look at "anticipatory selection"; we can show that all humans have one overriding genetic trait which evolved in advance of the invention of this weapon. Marvelous!

    You see, in every culture that uses spears, no matter where they are from, their other habits, their economic background or level of nutrition, all human beings throw a spear with the pointy end forwards. Such a stereotyped behaviour must be genetically determined; there is no way that it can be learned, since the trait is fixed in the population.



    This is a lie, obviously - we know it's learned behaviour. However, to ascribe the propensity for any such coordinated behaviour to genetic inheritance is still a little weak; without the environment of learning that brought about spear use in the individual, they would not have the behaviour at all.

    That's why genetic determinism is always a little weak as a metaphor for behaviour. (I won't even talk about memes...) See, saying something about behaviour like:

    "The genes code for learning behaviour. If a person grows up in an environment where multivariate calculus is taught, then they are genetically predisposed to learn multivariate calculus."

    Is a little like saying:

    "The genes code for living and dying behaviour. If a person grows up in an environment with no food, then they are genetically predisposed to starve to death."

    Do the genes really choose this?
     
  14. Buckaroo Banzai Mentat Registered Senior Member

    Messages:
    332

    Please Register or Log in to view the hidden image!

    Now that was surely a extremely exaggerated example!


    Surely not, and I've never heard of something like that*. The closest thing I've heard as about some sorts of bees that do or not do something according to their genes, something about cleaning their beeheeves, the "total" behavior was of "digging" a cell (I guess it was a cell, anyway, it doesn't matter, since they need to dig), and then throwing this content out of the beehives. But this behavior was divided in those two parts (or at least two), and may exist unusefully, when recessive, with bees that would clean the trash (i guess it was a dead larvae, must be) if there was not a layer of something covering it, and there's also the behavior of only digging and done, not completing the task. That was controlled by genes in a simple mendelian way, as confirmed by experimental breedings. But of course I do not think that all the behaviors, specially complex ones, are controlled simply like that, I really doubt that.
    Other thing like that, but closer to reality, is tendences of behavior in relation to sex. Besides the basic behavior difference (a tendence to copulate with the other sex), there are thinks related with parental caring and divisions of work, such as more sociability, and more "verbal intelligence" in women, while men are more mathematical and spatial. Of course that is very generic, there are no genes for a singing "Freire Jacques, dorme vous" or anything else. Even animals with not that range of capability of non-genetic behavior have a genetic dictatorship like you're suggesting. A pit bull, if trained to, can be docile as a siberian husky and huskies being agressive dog guards too. Likewise, is better to have caution with tamed tigers, even if they act like docile kittens, they still are tigers.
    Dog breeds remind me of a situation, that I don't know if is true for sure, although I heard that very often. Pointers and Setters (and maybe other breeds), have the natural tendence of pointing and sitting, respectively, without needing train to. That, if true, doesn't mean that this behavior is absolutely inherent and can't nonexist, but shows tendences influenced by genes. That's what I think is real, not that genes define wheter you can type in a keyboard or in a typewriter, use windows or the gui of linux, etc.

    ________________________
    * In fact, I remember of hearing once something brief about people having natural tendences of liking songs of their native countries, such as europeans liking classical, africans liking afro-ethnic or whatever. But i think that is simply nonsense, really.


    Why do you will not even talk about memes? I think that they're a great analogy for cultural evolution, and that at the same time helps to people understand biological evolution. Languages had their divergences due to geographic (or politic) isolation, and consequent restriction of the "memetic" flow. Is easy to see that neolatin languages are like each other due to common ancestry, as well as nordic languages... that's easy acceptable and pretty evident by almost anyone, unless a extreme incurable zealot believing in the Babel tower tale and linguistic fixism as a better explanation...
     
    Last edited: May 28, 2004
  15. John Connellan Valued Senior Member

    Messages:
    3,636
    I don't think anyone is saying that are they? I think it is quite clear that not only our physical properties but our mental properties have been selected for over the millennia to have some kind of advantage to our genes (and perhaps to the emergent individual too as has been noted

    Please Register or Log in to view the hidden image!

    ). The ability to learn maths comes from our brains logical abilities and this was certainly a useful trait which IS controlled by genes. Nothing to do with the present environment though

    Please Register or Log in to view the hidden image!



    As we have all said before, genes cannot choose anything but the individuals with a certain array of favourable genes will be selected for and survive.
     
  16. BigBlueHead Great Tealnoggin! Registered Senior Member

    Messages:
    1,996
    The point is that those of a deterministic mindset tend to assume that the gene is the ultimate player because it's a thing that they can see; much of the interest in genetics in popular science is rooted in the popular-science ignorance of other cellular mechanics. It's a sort of "when you have a hammer" problem.

    I don't like the meme concept because it's an insufficient metaphor rooted in the idea that things develop. There's a game called "conkers" where you and a friend smash chestnuts together until one of them breaks. The resolution of this game is not a process of "natural selection", even though it might have some superficially similar aspects. The world is full of "this is kinda like that" theories, and I think that the meme theory is one of them.

    Why?

    1) Memes are artificially selected. This makes the concept of meme development resemble animal breeding much more closely than evolution.

    2) Many memes are artificially selected by different standards. In the case of technology, people choose them for best human benefit. In the case of art, people choose them for distinctiveness/evocativeness. In the case of carriage (by which I mean the way that you go about doing things on a regular basis) people choose them by many different characteristics, recognition and repeatability being high on the list. The "evolutionary" model that people use to characterize memes may be sufficient to describe a few of these situations, but it's not really rich enough.

    3) A lot of memes are chosen to "pay out" in different terms than their own success. Consider the "I am the Prince of Nigeria" (or whatever) spam email that sometimes shows up in your mailbox. A successful meme, by the usual theory, would be one that propagated most widely. However, the "Prince of Nigeria" meme is a label for a scam, and the more widely it's propagated, the more likely it is to be found out and announced as a hoax. Thus, the people who are using the "Prince of Nigeria" meme consider its payout in monetary terms only, and so they are more likely to use the less successful meme - which might not have been exposed - than the more successful one which has been found out as a hoax. Ultimately memes are subordinated to a larger continuum of human intentions, and the concept of "evolutionary success" is insufficient to describe their operation and selection.
     
  17. John Connellan Valued Senior Member

    Messages:
    3,636
    OK but Im not talking about memes or cultural evolution. That kind of stuff must be passed down through generations I agree. All I am saying (and I don't even know if ur talking to me BTW

    Please Register or Log in to view the hidden image!

    ) is that most (if not all) of our behaviour can be explained the same way we explain the origins of our specialized organs ,such as the liver, and limbs etc.
     

Share This Page