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Are Humans Still Evolving?

  1. Oct 20, 2003 #1
    It may seem like civilisation has removed all of the selective pressures faced by wild animals, but Natural Selection acts on a lot more than superficial characteristics. Natural Selection is an omnipresent force shaping everything, even the things that we think we are choosing...

    http://physicspost.com/articles.php?articleId=172
     
  2. jcsd
  3. Oct 20, 2003 #2

    Njorl

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    I would disagree with the author in one way. I think that humans are not evolving very much. Because our environment is changing so rapidly, what is advantageous to one generation is often not advantageous to the next. Even in the developing world, where they don't have all the modern miracles of medicine and agriculture, they face different environmental challenges each generation.

    It is not so much the ease of modern life that nearly precludes evolution, but the rapid pace of change that does so. Evolution is too slow to keep up. The exception would be in areas that are always advantageous. As far as I can tell, being more intelligent is always useful.

    Njorl
     
  4. Oct 21, 2003 #3
    As the first teacher I made friends with at my new university said: "progress is always happening. just have to figure out where it is going".
     
  5. Oct 21, 2003 #4

    Monique

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    Does evolution need to be a positive thing? I mean, with our technological advances we have placed biological improvement outside of ourselfs.

    Humans, normally destined not to reproduce are now getting children, passing on genetic defects that would normally have been selected against. I think humans are evolving, but not in a good way..
     
  6. Oct 21, 2003 #5

    Monique

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    Njorl, how does being intelligent give someone an edge at better reproduction? In this society being intelligent actually decreases the number of children taken by such a person, right?
     
  7. Oct 21, 2003 #6

    Njorl

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    You are confusing advancedness with intelligence. Those who have access to all the modern amenities of life have fewer children because they are not as dependent upon them in their old age. Also, their children's lives are at less risk, so they need fewer of them to maintain their legacy. There are plenty of stupid people born with silver spoons in their mouths who fit in this catagory. There is probably little or no difference in intelligence between highly developed and third-world countries.

    Intelligence always helps though. All other things being equal, an intelligent subsistance farmer or herder will do better than a stupid one. An intelligent businessman will probably be more successful than a stupid one. Economic success does help propogation. While it is rare that a successful businessman will be so repellant that he can not marry, it might happen, but a little more money makes it less likely. Also, some very wealthy men divorce and start new families with young "trophy wives". Lastly, wealth allows more attempts at fertility procedures like invitro fertilization.

    Njorl
     
  8. Oct 21, 2003 #7

    Monique

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    .. I don't agree ..

    In order to look at this you need to evaluate people from the same culture, they are all at the same level right? Intelligent people who do well with their education and land good jobs will choose for smaller sized families. First of all, who takes care of the kids when both are working? Second, they are smart enough to use protection the right way.

    Ofcourse, this is a hard thing to really assume, some statistics would be needed.
     
  9. Oct 21, 2003 #8
    But doesn't that just increase the variation (which is the first part of the definition of evolution put forth by the author)? Wouldn't the new challenges that humans have to face cause greater variation, and even greater selection pressure (what with all the new illnesses that can be contracted and the over-population of many regions, as well as the rapid loss of resources)?
     
  10. Oct 21, 2003 #9

    Njorl

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    Yes, but evolution takes more than a generation or two. If a challenge comes and goes faster than a generation, evolutionary changes have no effect. Black plague was rampant in Europe for 300 years. Even though a rare gene gave significant protection from it, that gene did not spread to the majority of the populace even over more than 10 generations.

    Njorl
     
  11. Oct 21, 2003 #10
    And what about the fruit flies that evolve an immunity within one generation to certain toxins? This has been experimentally verified.

    Also, what about the so-called "super bacteria" that can evolve when one constantly uses antibacterial soap?
     
  12. Oct 21, 2003 #11
    I definitely believe humans are still evolving. The question is: How are we evolving?

    This may be slightly off topic, but I believe that as with other natural occurrences, humans are beginning to replicate the process of evolution. If we momentarily set aside the notion of natural evolution, we can see that technology is itself changing human roles and identities. As humans have done with most other aspects of nature, we are beginning to take control of our own evolution. It may not be long before natural selection plays a lesser role in evolution than personal choice.

    I believe that we are standing upon the fringe of a cybernetic age. It may not be long before we see the dawn of a new human form: one, which contains mechanical, and even robotic parts. Certainly we are almost there, with our current prostheses and organ replacements. Indeed the time may soon come when such mechanical replacements are made through choice, rather than medical necessity. Granted this may not constitute classical evolution, as such mechanical traits are non-hereditary, however it does establish a change in the species. Of course, with regard to technology, this does not even scratch the surface of possibilities for human controlled evolution. Control over classical evolution can be established with such concepts as gene therapy and human cloning, not to mention the ever-controversial designer baby.

    Although I do believe that humans are still naturally evolving, I feel that our own technology poses a greater opportunity for change. With the aforementioned technologies of the coming age, we must take measures to safeguard that such human controlled alterations of the species does not become relegated to matters of the trendy and fashionable. As such human modification becomes viable, improvements to one’s genetic self must not be limited to one’s socio-economic status. So in the end, the real question is not about whether or not we are evolving, but whether or not we are doing so responsibly!?
     
  13. Oct 23, 2003 #12

    Phobos

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  14. Oct 27, 2003 #13

    Another God

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    hehehe....'the author'....hehehe

    The point of the essay was largely to point out that it is for this reason, combined with the fact that we can't judge the standards upon which NS works, we are most likely still evolving. You say that there is too much change for evolution to get a trend built up, but how can u say that when no one has any real idea what it is that NS is selecting?

    NS is much more pervasive than just our fitness, and our intelligence. These superficial traits may mean nothing when some new HIV mutant hits which makes it airborn (to create an exagerated possibility).

    The point is: We don't know what NS is selecting, but it is always doing it; and Evolution takes effect over thousands of years. Although we may not be noting any net directional change right now, the variation is building up, shifting and moving around, waiting for the moment of mass directional selection to hit.
     
  15. Oct 27, 2003 #14

    Another God

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    Gene therapy is my real interest RE the control over future human evolution. I think Mechanical additions to the body have nothing over a genetic manipulation of the body. Even the designer baby idea is only a one of thing, while the gene therapy idea is an idea that can be applied ot anyone at anytime.

    With time we will understand genetics to the point where we can not only do perfect gene therapy, but we will understand how developmental control is acheived and how growth is regulated etc. We will then be able to design new limbs, new attributes etc, and just administer them to ourselves in a syringe or something. And then wait for a year or two as the new parts grow. (PS: True gene therapy (with retroviruses) incorporate the DNA into our genome, so they will be passed to the next generation)

    I don't know how you could stop the genetic modifications being limited to one's social status: Everything else is. What makes bodily modifications different to anything else?

    One of the truley strange side effects of being able to control the very make up of our own body, is that we have the potential to change everything about ourselves, including our desires, our likes, our dislikes, what causes pain and what causes pleasure etc. We have the potential to re-wire our brains so that 'hurting ourselves' feels good for instance.
    I think this will destabilise society (since our society is really only a result of evolution creating us to desire being in a society) as people alter themselves, no longer desiring to be in society, and...well, yeah, all hell breaks loose.
     
  16. Oct 27, 2003 #15

    Another God

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  17. Nov 2, 2003 #16
    Back to the original question about evolution of humans. Evolution is certainly more predominant in novel environments,due to selective pressures. So, in the case of humans in civilized nations, a change in allele frequencies will be very unprobably.

    But, what about reverse evolution or "devo". People are fat today b/c that is what humans needed to survive. But it would seem with the rise in obesity in children, their chances of reproduction will be slightly lower. So will obesity dissappear???

    Yes, I know that medical advances will never allow this to happen, but what if medicine was left status quo???

    Nautica
     
  18. Nov 3, 2003 #17

    Phobos

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    No such thing as de-evolution. Evolution is simply Change, with no preferred long-term direction.

    Given enough time (generations), yes, it is conceiveable that fat storage mechanisms/tendacies can change. But only a small portion of the world's population benefits from new medical advances. And a significant fraction of the world's population is still more worried about finding food than keeping off weight.
     
  19. Nov 3, 2003 #18
    I realize that there is no such thing as de-evolution - evolution is only a change in allele frequency within a population - but considering the fact that at one time humans survival was based on be able to store energy or fat - now what once was an advantage is now a disadvantage.

    As far as your second statement - I am only speaking of industrialized nations and especially the US and Great Britain - within our population - be able to store fat is a major disadvantage, which will only get worse until we find the "magic" pill.

    Nautica
     
  20. Nov 4, 2003 #19

    Phobos

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    Agree (under current circumstances of our abundant wealth/resources)

    Two things will probably be needed (1) US/UK isolates itself reproductively from other peoples (currently not the case), (2) lots & lots of generations living under the same conditions of abundance (here's hoping...)
     
  21. Nov 5, 2003 #20

    FZ+

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    Good paper on this:

    http://www.complexity.org.au/vol09/dopazo01/

     
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