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Evolution and statistics

  1. Dec 20, 2007 #1
    Let me preface this by saying that economist Gregory Clark argues in "A Farewell To Alms" that one of the factors for the success of the industrial revolution was evolutionary in nature: disease killed off poorer members of the society and their position was taken over by sons of the wealthy who were less violent and more productive, thus creating the conditions needed for the industrial revolution.

    What I'd like to do is get my hands on some research on:

    1. What percentage of people (broken down by countries perhaps) die without passing on their genes?
    2. Which traits are more common among those who don't pass on their genes?
    3. Which traits are more common among those who do pass on their genes?

    Has anyone come across any research on these topics?

    The idea is that by seeing what kind of people do and don't contribute to the gene pool we can predict the face of the future society.

    If we can find data going back far enough, we should be able to identify the effects of different cultural ideas on the gene pool.

    Using this information in combination with data from psychological tests from years ago, we might even be able to quantify how psychological traits correspond with reproductive success.

    And most importantly of all, consider the social engineering possibilities. Governments could put in place policies designed to encourage the reproduction of workers with high IQ while discouraging the reproduction of those with low IQ. The effects should be obvious in just a couple of generations and result in a high-tech society.

    So. Has anyone come across any research into these ideas?
  2. jcsd
  3. Dec 20, 2007 #2


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    The reasons why these assumptions are all generally wrong have been discussed a number of times here.

    For example, your last paragraph about selecting for a "high IQ" should be fairly obvious, even if you could breed people to have high IQ's, that doesn't mean that these people are rational, sane or have motivation, they would not be born educated, you would also have to ensure that everyone was educated equally, but then you go back to the issues of motivation, etc... They could all turn out to be evil and corrupt, what makes you think an IQ test score somehow imparts honesty or compassion?. Another obvious issue is that if you were able to breed everyone with equal intelligence, who would do the menial jobs?
  4. Dec 20, 2007 #3

    jim mcnamara

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    I'm using a definition of random that may not match yours, so read with care.

    Aside from bad assumptions which Evo mentioned, Natural Selection works at random. For example Mozart died leaving two of six children alive. None of his children had any children. Mozart's contributions to the gene pool were lost, assuming that there are musical genes. Just because somebody has a better education or a rare trait does not make him able to dodge an out of control bus on the side walk. Or death from influenza.

    q1: this is a local population issue, there isn't a good statistic. In parts of Africa with high infant mortality, way less than 50% of people born have children. Other places the numbers go up. What really counts is how many children a mother has that live to have their own kids. Who survive to reproduce. It is not the percent, necessarily.

    q2 & q3: there are no good answers to this, see the Mozart example, Natural Selection is random. What is good for survival this year, may be neutral or very bad next year.

    What contributes most to the future generation's gene pool is which populations continue to have relatively more children survive to have children than their neighboring populations, nothing else. What you'd have to do is find all of the million+ or so local populations, track births, deaths, immigration and emigration over a few generations, then you could guesstimate based on historical data what things might be like in the future. Until a flu pandemic completely rewrites the book, for example. Remember the "random" aspect...

    Individual traits may or may not have any selective advantage or they can be double edged, like sickle cell anemia. Thalassemias like this allow humans who are heterozygous for the disease to survive malaria. A plus. Children who are hohomzygous die young from the disease instead of dying from malaria. A big minus, especially in places with no malaria. The point is you cannot reasonably predict, a priori, which trait is going to help an individual survive in a given population.
  5. Dec 21, 2007 #4
    No, by definition natural selection is the "non-random reproduction of genotypes". You confuse mutations (which are random events) with natural selection (which is 100% non-random)
    Not so--here is one example of which I am aware. Dr. Alberto Plleroni at Harvard University has for years studied the predator-prey interaction between falcon and pigeon. To make a long story short, he predicted that a trait found on some pigeon, white rump feathers, would help individual pigeon survive falcon attack. To test this prediction he switched rump feathers between white rump and blue rump individuals and found that previous blue rump individuals now with white rump had much higher survival rate, and those previous with white rump and now with blue a much lower survival rate. I suspect there are many such examples in the peer reviewed literature on evolutionary theory.
  6. Dec 22, 2007 #5

    jim mcnamara

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    No I do know the difference. I did not communicate it. In that respect you are completely correct. my bad.
  7. Dec 22, 2007 #6
    i would say the only thing that we control today with breeding is skin,hair and eye color and maby and i mean maby phasyce now animal are a difrent story there like clay
  8. Dec 22, 2007 #7
    Any attempts at any forms of eugenics will most likely end in catastrophe for the human species, because we have no idea what traits are 'better' or 'worse'. In general, this comes for the myth of progress.

    A hypothetical example: Say we select for stronger immune system. Then stuff like H5N1 comes along and incites a massive cytokine storm in a higher frequency of the population than it would otherwise.

    There are known unknowns, but there are also unknown unknowns.
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