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Thread: The human eye and evolution...You Gotta Wonder

  1. #1 The human eye and evolution...You Gotta Wonder 
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    After a yearly eye exam this afternoon, my optometrist left me with a perplexing statistic: Half of living humans will require some form of vision correction before the age 40. After 40 most will require correction. Half? Most??

    While merely an "observation", it would seem to me that vision would have to be the most crucial sense evolution endowed to human survival. And yet, without correction, half the young and most of the elderly would be feeling around in the daytime?

    From experience I can attest that without personal eye correction, my day to day would cease. No driving, no work, no tv, no visible life.

    Obviously one will rarely see the other 4 senses forgotten by evolution as much as vision which inevitably lead to my next question: Were our primate ancestors exposed to a simalar plague? If so perhaps vision itself is becoming a sensory reaction of the past. How else can this be explained? Unaided, how would our animal anscestors have survived being unable to visibly distinguish between friend or foe at the soonest possible millisecond?

    In the (wild) animal kingdom, abnormalities, disabilities, deformations and sickliness are dealt with in a cruel, yet swift and severe manner. Were humans to follow this instinctual behavior I fear the optemetric world would be completely unnecessary.

    While recent innovations in the "fixing" of eyesite through some form of surgical procedure has become an option, it still appears as two steps backward in the evolution of an imperative sense. Ask someone who's completely lost their site...Thanks


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  3. #2  
    Him
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    Forum Sophomore Him's Avatar
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    I think reaching 40 of age would be nice for our animal ancestors.
    Furthermore I think eye corrections are needed because of many reading (close sight) and thus corrections for far sight. So indeed typical these days…


    he who forgets...will be destined to remember (Nothing Man - Pearl Jam)
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    Universal Mind John Galt's Avatar
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    As Him has pointed out surviving to forty years of age would have been a majore accomplishment for our ancestors. The eyesight problems that come with old age would not, therefore, have been an issue.

    Many eyesight deficiiencies that are corrected are quite minor and sometimes effect only one eye. The overall deterioration in sight is thus insignificant for most individuals. The occasional unlucky one perishes because of that deficiency: natural selection at work.

    And without the culling by nature of those with these and more serious weaknesses , because we have found away to compensate for them, they must become more prevalent.: exactly as we see happening today.

    [And don't forget that it is in the interest of opticians and optometrists to find as many defects as possible. That's how they make their living.]

    Since the world beyond six feet is a blur to me I am at a distinct disadvantage without my glasses. Nevertheless I can still flawlessly pick out friends I am meeting at the airport or in a bar from their body postures, size, movement and colour of clothing. I imagine a por sighted chimpanzee could pull a similar trick.
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    I'd suggest a couple of points. First, as the other contributors have said, getting past forty is a fairly new experience for the human race - and if you check out the statistics for Sierra Leon you'll see it satill isn't the norm.

    Second, imagine our ancestors in a hunting party wandering across a plain somewhere. Someone sees a lion/wolf pack/large dangerous creature of your choice. He tells everyone else, therefore, even someone like me, for whom the world beyong the length of my arm becomes rather fuzzy, is aware of the danger and all I'd have to do is to be able to see which direction everyone else is running in to head the right way. This analogy can also be applied to any other species.
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    Forum Isotope Zelos's Avatar
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    human didnt live so long before, so the need of having correct eye-sight after 40 wasnt so important. So thats y eyes dont keep up for so long. Most humans were probebly dead at that age
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    Forum Cosmic Wizard spuriousmonkey's Avatar
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    I walked around for 25 years without glasses despite not having that great eyesight. I could still function in society. Nobody dies from having 10% less eyesight. There might be a chance that people who have 10% better eyesight have a higher reproductive success than those with normal eyesight. That doesn't imply you can't reproduce with 10% less eyesight.

    When a human reaches the age of 40 he is also not as fit (as in good physical shape) as when he was 20. He can't run so far anymore, can't jump so high, can't stretch so far. Still, you don't really see people who hit 40 dropping dead like flies.

    In evolution all is relative. 10% less eyesight at the ripe age of 40 doesn't mean much. Most people have reproduced before that age to start with. That would mean there isn't any selection pressure anymore.

    Moreover, when a human hits 40 he has other things to compensate for the loss of eyesight. Experience. Maybe he can't see so well, but he knows where to look.

    Nothing in nature is optimal. Everything is on a level that is adequate.
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    Forum Professor Zwolver's Avatar
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    I am 21 and have a strange eyesight condition as well.. proteine bubbles in my glass eye body. Not affecting anything.. but i can't focus on 1 point for that long because then the bubbles or spots combine to 1 big one..

    :? there are medicine for it in testing, but they are not hurrying it because it's nothing severe and there are just several thousand people suffering from it..

    still ... what is 10% less eyesight.. the doctor said i have perfect eyesight. if i use methods to mix the spots.

    by the way... don't underestimate the human age... people from the stoneage have been found who lived up to at least 65. They were dead when they found them though.

    In the middle ages the age went down to an average of 34 (50% of all with an age above 12 died).

    roman times were at an average with 51.

    now it increases rapidly. man ofcourse faster than women. man at 80 and women at 84 (or something)
    Growing up, i marveled at star-trek's science, and ignored the perfect society. Now, i try to ignore their science, and marvel at the society.

    Imagine, being able to create matter out of thin air, and not coming up with using drones for boarding hostile ships. Or using drones to defend your own ship. Heck, using drones to block energy attacks, counterattack or for surveillance. Unless, of course, they are nano-machines in your blood, which is a billion times more complex..
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    Perhaps you should consider that humans are to an extent "immune" from, evolution and natural selection. There isn't really such thing as survival of the fittest; almost all of us survive unlike most animals in the wild.

    Aside from the eye problem you're discussing there are many other examples of where we intervene with evolution. For example; If you get an infection, your immune system may not be able to fight the infection naturally but antibiotics can compensate so a good immune is no longer an evolutionary requirement (for humans).

    I'm sure you can make a similar case for our need for glasses. i.e. bad eyesight will not prevent us surviving long enough to produce offspring and pass our bad eyesight onto the next generation...
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