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Author Topic: Why have short-sighted people not died out?  (Read 3488 times)

Offline Erin

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Why have short-sighted people not died out?
« on: 28/09/2009 09:30:04 »
Erin asked the Naked Scientists:
   
Dear Naked Scientists,

I recently had LASIK surgery to correct a severe near-sightedness and am now seeing great!   My new-found vision got me to thinking: if I had been born before glasses or contacts were around, I surely would have had a huge disadvantage in life?

When humans were evolving as hunters and gatherers, I can only imagine that people with vision problems would be at a much greater risk of dying earlier due to starvation if they could not hunt or gather well or due to predator attacks.  

Based on the concept of "survival of the fittest" I would have expected that poor eyesight would have been evolved out of the human species, but obviously it was not!

Can you explain why?

Erin from Chicago, USA

What do you think?


 

Offline Bored chemist

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Why have short-sighted people not died out?
« Reply #1 on: 28/09/2009 09:48:19 »
Because we are useful.
I am very short sighted and can often see things like splinters that others can't.
Since humans are a social species this diversity among individuals provides advantages that, for the species as a whole, outweigh the disadvantages for the individual.
 

Offline Erin

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Why have short-sighted people not died out?
« Reply #2 on: 30/09/2009 16:37:39 »
Seeing splinters is great, but I would think it would be more useful to see the saber tooth tiger 15 feet away from you…
 

Offline Don_1

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Why have short-sighted people not died out?
« Reply #3 on: 30/09/2009 17:02:05 »
You could ask the same question of those who are long sighted, blind, deaf, mute, short, tall, fat, skinny, knock kneed..............

Where do you stop? Left handed, got acne?????

Very, very few people are perfect (yours truly excepted, of course*). If evolution were to wipe out every minor defect, it would need to wipe out the DNA at the root of the defect. That would result in there being virtually no life on the planet. That said, those minor defects can prove to be an improvement and thus a small but significant change may creep in to the species.

"A monkey without a tail!!! How absurd. Oh, I don't know though."




* I can just hear the echos of 'Me too' from other TNS members.
 

Offline Bored chemist

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Why have short-sighted people not died out?
« Reply #4 on: 30/09/2009 18:28:56 »
Seeing splinters is great, but I would think it would be more useful to see the saber tooth tiger 15 feet away from you…
I'm short sighted- not blind. I might not be able to recognise the tiger but I would see it.
Incidentally, unless you are seriously armed 15 feet is a bit too near.
 

Offline RD

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Why have short-sighted people not died out?
« Reply #5 on: 30/09/2009 22:25:12 »
Just before this thread turns into an advert for LAZIK eye surgery.
There are risks  associated with this procedure ... http://lasikdisaster.com/
Eyesight changes with time: this eye surgery will only give 10-20 glasses-free years.   
 

Offline JnA

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Why have short-sighted people not died out?
« Reply #6 on: 01/10/2009 01:52:04 »
Erin asked the Naked Scientists:
   

Based on the concept of "survival of the fittest" I would have expected that poor eyesight would have been evolved out of the human species, but obviously it was not!

Can you explain why?

Erin from Chicago, USA

What do you think?



1. vision can be degenerative, genetically and environmentally.

2. 'Survival of the fittest' is misleading. 'Survival until one can produce offspring' is evolutionary.


 

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Why have short-sighted people not died out?
« Reply #6 on: 01/10/2009 01:52:04 »

 

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