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Thread: Cancer and the human species

  1. #1 Cancer and the human species 
    Forum Ph.D. verzen's Avatar
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    I was talking with a friend bouncing idea's back and forth and I came up with the thought that cancer is the direct result of an unnatural or natural process damaging the genetic code. The damaged DNA is multiplied and and body causes cancer as a self destruct mechanism to preserve the species and to prevent that particular individual from multiplying and further damaging the species. Cancer is a type of cleansing device to help make sure that the human race stays pure of unnatural alteration. So cancer is built to preserve and protect life.

    Any opinions?


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  3. #2  
    WYSIWYG Moderator marnixR's Avatar
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    no - cancer is just like old machinery going faulty : due to degradation of the DNA in body cells programmed cell death doesn't happen as it should, and cells that should have died start taking up a lot more of the food supply than they should

    besides, i don't know of a single instance where evolution happens FOR a certain purpose, let alone in order to preserve the purity of the race
    natural selection may well weed out unfit individuals, but equally so natural selection's definition of unfit may well be different of what the racial purists think it is


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  4. #3  
    Forum Cosmic Wizard paralith's Avatar
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    Additionally, even though the term cancer covers a broad range of conditions, the term by no means encompasses ALL deletrious mutations. There are many, many other ways in which mutations manifest themselves which are nothing like cancer. And even with some cancers, if you manage to reproduce just as many children as a guy without cancer does before you die, then no "cleansing" action will have occurred.
    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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  5. #4 Re: Cancer and the human species 
    Moderator Moderator TheBiologista's Avatar
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    Quote Originally Posted by verzen
    I was talking with a friend bouncing idea's back and forth and I came up with the thought that cancer is the direct result of an unnatural or natural process damaging the genetic code. The damaged DNA is multiplied and and body causes cancer as a self destruct mechanism to preserve the species and to prevent that particular individual from multiplying and further damaging the species.
    Three problems.

    1. The mutations which cause cancer are generally quite well known. They are not generically "harmful" in any sense except that they cause cancer. So this is not a reaction to some other form of "harm". Not all harmful mutations cause cancer, in fact only a small subset do- those that affect control of cell division.
    2. Unless the mutation occurs in the germ line, it won't be passed on to another generation.
    3. An embryo with such mutations would not be viable. Obviously enough since the embryonic cells will grow out of control thus preventing normal embryogenesis. This is a much more obvious control point and one which is consistent with natural selection

    Quote Originally Posted by verzen
    Cancer is a type of cleansing device to help make sure that the human race stays pure of unnatural alteration.
    Unnatural alteration does not exist. Mutation is mutation. It may benefit, harm or be neutral. The source is irrelevant and evolution does not discriminate. To suggest that cancer patients are in some manner being naturally "cleansed" from the population is without evidence and could be taken as rather offensive.

    Quote Originally Posted by verzen
    So cancer is built to preserve and protect life.
    Cancer is not built. Full stop. It has no purpose. It is not selected for.
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  6. #5  
    WYSIWYG Moderator marnixR's Avatar
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    one more reason why cancer is often oblivious to the effects of natural selection is that most people get it after they've finished having children

    this means that on average people who get cancer have the same number of offspring as people who don't, hence there's no differential reproductive success for natural selection to work on
    "Reality is that which, when you stop believing in it, doesn't go away." (Philip K. Dick)
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  7. #6  
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    Quote Originally Posted by marnixR
    one more reason why cancer is often oblivious to the effects of natural selection is that most people get it after they've finished having children
    Uhh... flip that around, please. Organisms in a closed system must have offspring and then die for natural selection to work. If the environment won't kill us then we need self destruct systems.

    This is not "cleansing" by the way. It's because our genes, as a group, survive environments better when a small fraction evolve. Reproduction answers that. Even if our bodies could perfectly regenerate forever, our genes would still be better off shedding outdated bodies. Reflect that toads champion most of the same genes we do. It's a robust strategy.

    Quote Originally Posted by TheBiologista
    Cancer is not built. Full stop. It has no purpose. It is not selected for.
    This great distinction between allowing something to happen and causing it to happen?
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  8. #7  
    Moderator Moderator TheBiologista's Avatar
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    Quote Originally Posted by Pong
    Quote Originally Posted by TheBiologista
    Cancer is not built. Full stop. It has no purpose. It is not selected for.
    This great distinction between allowing something to happen and causing it to happen?
    You'll need to elaborate a bit there, I'm not sure what you're getting at.
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  9. #8  
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    How actively must an individual ensure its own demise? Well, we needn't explode or anything. The lazy way is just to maintain integrity as long as appropriate, then let it go. That's how one causes something to happen by allowing it to happen.
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  10. #9  
    Forum Cosmic Wizard paralith's Avatar
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    Quote Originally Posted by Pong
    Quote Originally Posted by marnixR
    one more reason why cancer is often oblivious to the effects of natural selection is that most people get it after they've finished having children
    Uhh... flip that around, please. Organisms in a closed system must have offspring and then die for natural selection to work. If the environment won't kill us then we need self destruct systems.
    ...no, marnix is correct, Pong. Natural selection works on differential reproductive success. If cancer only has an effect on people who have reached the end of their natural reproductive lifespan anyway, then there will be no reduction over time of the number of genes with cancer-enhancing mutations in the population, unless it happens by chance, in which case it is not natural selection.

    Perhaps you're referring to one of the proposed causes for natural senescence, which is that if organisms lived forever instead of reproducing and dying, there would be no chance for variation to occur and populations would not be able to respond to changing environments. In which case, it may be possible that some cancers are the result of the body's programmed failure to maintain itself. But this is no way contradicts what marnix and I are describing.

    I don't know much about cancer biology but I would imagine that that theory is testable - for example, younger reproductive aged animals transfected via electrophoresis with certain cancer-causing mutations should be able to identify and kill the cancerous cells, whilst older animals near the end of their reproductive cycle will not be able to handle that same mutation and will die from the cancer.
    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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  11. #10  
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    Quote Originally Posted by paralith
    Natural selection works on differential reproductive success.
    Right. And death is essential to success. How and when varies, but typically it's soon after guaranteeing the next generation. If you're a tree, that could take centuries. If you're human, you might metagame a bit by helping with the next, next generation. If you're a fruitfly, well, how fast can you type?

    I think we all agree aging does have a "purpose" (am I allowed to use that word :? ) - which is death. So how do we accomplish this? I suggest we let it happen. Allowing something is an action. If one's genes allow the joints to seize up at a certain age, that is not coincidence. It's a strategy to ensure we die at an appropriate time. Why would timed susceptibility to cancer be any different? We don't like it so we've decided it's foreign?

    Half of all dogs get cancer, and a quarter die as a direct result of it. Dogs live about twelve years (oddly wolves live about twenty in captivity - another topic!). Those cancer deaths are relevant to gene survival in dogs: the grieving dog lovers adopt a puppy! :-D
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