Godless Dave

I don't think there is one. But it doesn't seem to confer much of a disadvantage either.

Exactly. The whole "human eye is irreducibly complex, therefore it was designed" always rubs me the wrong way, because my vision is approximately 20/300. Without corrective lenses anything farther than two feet away is just a blurry shape. Some perfect design.

Wounded King

Actually I was going to use Ireland as the setting, but then I decided it would be both misogynistic and racist.

Ensign Steve

Sorry, not silly at all. Color blind people are harder to fool with camoflague. The army uses color blind soldiers to spot enemy troops, trucks and buildings that are trying to hide under camoflague nets.

Besides, it was only brought up to show that a color blind eye is not useless.

Ensign Steve

Thank you soooo much!

Quote:

I suggest that this is evidence against Intelligent Design, as it implies that any purported Designer must be an absolute idiot.

Either that or he likes octopi more than man. So we're, what, third now? After octopi and beetles? Heehee.

caravelair

well, i think the original dude was talking about our eyes changing from a previous state, so i was suggesting that as a hypothetical state that our eyes could have evolved from. not that it would be more useful, that our eyes would be more useful after the change and yet still have evolved from a "useful" eye through a small mutation. i guess i was trying to answer 2 questions at once and it got kind of confused.

caravelair

ha ha. i've never heard it put so eloquently.

RufusAtticus

From some work I did on Christian Forums, in responce to Sean Pitman, who later incorporated it into his webpage without any reference to me:

Twenty three replications occur to form an ovum. At the onset of puberty the male germline stem cells have gone through an estimated 30 cell divisions and then one every 16 days there after. Then in sperm formation there are 5 more replications. (See figure 2 in the following paper). Therefore, sperm will have gone through anywhere from 35 to >900 cell divisions by the time they meet the egg. Clearly the number of point mutations an offspring has is mostly affected by the age of the father.

From, Crow JF. (2000) "The origins patterns and implications of human spontaneous mutation" Nature Reviews Genetics (1) pp40-47.

So if we take 25 years as the mean generation time, NA = 265. Therefore the number of point mutations an offspring has compared to its parents can be calculated as follows.
If mu = 1e-10 point mutations per bp per replication (0.33 pms per human haploid set per replication), then offspring will inherit ~92 point mutations. And this is on the low end of our error rate.

If mu = 1e-9, then the offspring will inherit ~920 point mutations. And this is probably on the high end for a person with a 25 year old father.

If mu = 5.5e-10, then the offspring will inherit ~506 point mutations.

If mu = 3.16e-10, then the offspring will inherit ~291 point mutations.

Now Nachman and Crowell (2000)'s estimate of 2.5e-8 point mutations per nucleotide per generation gives an answer of ~160 point mutations (2.5e-8*6.4 gbp). This is clearly within the range prediced by the error rate per bp per replication.

Now considering that ~130 million babies are now being born every year, it's clear that it won't take 100,000 generations to get an advantageous point mutation.

KC

I think it has to do with sexual selection. Colour-blind males cannot compete for mates as well as normal males, because they cannot coordinate their clothing (sexual displays) properly. Left to themselves, they dress in clashing colors and drive females away.

To compensate for this, however, they will ingratiate themselves with sympathetic females, taking advantage of their nurturing instinct. These females (like my sister-in-law) invent elaborate systems to mark clothing so that the male can properly color-coordinate his display.

Clever bastards.


KC

hyzer

This might be an apocryphal story, but I understand that color blind persons are less likely to be fooled by camouflage coloring. In fact, during WWII the Army sought out color blind persons for artillery spotting and forward reconnaissance. Perhaps it is not such a leap to imagine that survival pressures would keep color blindness around as it might not have been a fatal trait in early hominids.

Ensign Steve

I feel like I'm having deja vu. Well, at least hyzer had the decency to admit that it may be apocryphal. I just went ahead and pronounced it as fact! Truth is, "I heard it somewhere." But I never cited my source, so I knew it would be taken with a grain of salt.