On the premise that God or Nature is not random and that body features all have a purpose, why do we have fingerprints? Why not just normal featureless skin? Why are they relatively unique?

Gription.

Grip....unique because we all grow based on our unique combination of DNA.

Grip. Interesting. Friction and siping? Or primarily siping? I wonder how effective it is relative to normal skin. Now I wonder if fingerprints were deeper in the beginning vs today. Functionally more important before civilization?

DNA I guess makes sense like how faces are difficult. But then again, not sure why it we couldn’t all have the same fingerprint just like kidney tissue or something.

Anyway, was just curious after watching something on tv. Thanks.

quote:

Originally posted by konata88:
Grip. Interesting. Friction and siping? Or primarily siping? I wonder how effective it is relative to normal skin. Now I wonder if fingerprints were deeper in the beginning vs today. Functionally more important before civilization?

DNA I guess makes sense like how faces are difficult. But then again, not sure why it we couldn’t all have the same fingerprint just like kidney tissue or something.

Anyway, was just curious after watching something on tv. Thanks.

Every part of every person is unique. If you measured people's kidneys thoroughly enough, you'd discover minute difference in density, size, shape, weight, orientation. We use fingerprints because the way we describe/measure/characterize them was easily standardized. We could have technically have used any other body part, but precision of measurement would have added additional room for error.

As for grip effectiveness, remember that your hands sweat but does not produce oil.

Fingerprints exist to enhance grip via friction. It's also not strictly related to DNA. Identical twins do not share fingerprints. Ridge detail is a combination of DNA, environmental effects in the womb, and pure old fashioned randomness.

Thinking about finger prints in an evolutionary sense, its hard to imagine a mutation of finger printed ancestors being naturally selected over smooth skin fingered population. Maybe we got them from alien ancestors.

It doesn't seem like the feature would be advantageous enough to eventually erase smooth skinned finger population. But it apparently has.

Since we come from birds and fish, It could be viewed as a subtle version of bird feet that are kind of gnarly and possibly for walking traction.

It's accepted that the reason our fingers wrinkle when waterlogged is to aid in gripping wet objects.

As for possible further evidence, has anyone ever burned their fingertip smooth? Even after the burn had healed, it does make gripping a pen troublesome, until the skin grows back.

quote:

Originally posted by Gibb:
It's accepted that the reason our fingers wrinkle when waterlogged is to aid in gripping wet objects.

As for possible further evidence, has anyone ever burned their fingertip smooth? Even after the burn had healed, it does make gripping a pen troublesome, until the skin grows back.

Yep happened to me. Things kept jumping out of my hand like they were greased.

quote:

Trivial question. Fingerprints.

What did you do?

quote:

Originally posted by V-Tail:

quote:

Trivial question. Fingerprints.

What did you do?

Lie

Deny

Counter-accuse

Natures barcode for humans.

Fingerprint examiners call all skin with ridges (fingers, palms, toes, soles) “friction skin.” From an evolutionary standpoint, being able to hold onto things tightly and to walk or climb without slipping is extraordinarily critical to our survival, so friction on those surfaces is vital. As stated, even identical twins don’t have the same friction skin patterns (fingerprints), and I’ve never seen a detailed convincing explanation of why; most just seem to come down to “That’s what happens.”

(I don’t, BTW, believe that the skin on our fingers gets wrinkled from prolonged immersion in water to help gripping. If that were important, it should happen immediately. In any event, it seems to me it happens because the skin absorbs a little water and expands or gets bigger. That in turn means it must wrinkle to remain attached to the underlying tissue, and because it no longer fits properly.)

quote:

Originally posted by Gustofer:
Gription.

Yep.

If only we had the teeny little hairs (setae), too, we could climb walls like Spiderman.

I think it's also likely that, given the total human population at any given time, that there are repeats of fingerprints, or ones close enough that they seem the same.

Ever met your or your friend's doppelganger, a random unrelated stranger who looks just like your friend/cousin/etc? I've met several, over the years. I bet if we had a single database of every humans fingerprints you'd find several duplicates, even if its purely random. Bake a few billion apple pies, a few will no doubt come out exactly the same.

Doh! Isn't it obvious that without fingerprints one could not get their CCW?

quote:

Originally posted by Aeteocles:
We use fingerprints because the way we describe/measure/characterize them was easily standardized. We could have technically have used any other body part, but precision of measurement would have added additional room for error.

Look up Bertillon. He originated a method for identifying criminals by taking various measurements of their bodies. Of course, the variability involved was why it was superceded by fingerprinting.

quote:

Originally posted by 46and2:
I think it's also likely that, given the total human population at any given time, that there are repeats of fingerprints, or ones close enough that they seem the same.

It also depends on what method you use for matching fingerprints. IIRC, the investigation into the 2004 Madrid training bombings led to an American citizen because his prints matched those found at the scene. Except he had never been to Spain. As it turned out, European authorities used fewer points of reference for matching prints than is typically used in the US. They ultimately did lead to another, more plausible suspect.

Also, I believe I read a report a few years ago regarding the statistics involved in fingerprint analysis. As it turned out, the idea of fingerprints being unique was based more on assumption than scientific testing. Last I heard, there were researchers looking into testing the scientific validity of fingerprints' uniqueness.

As an aside to the subject. It's interesting to google animals that have fingerprints. And to discover that Kola's fingerprints are almost identical to humans even under microscopic examination..........So that fingerprint of a killer might just be a KOLA !!

The *only* way to know for *certain* if they are 100% unique, even if only limited to those humans who are currently alive, is to have a single database of them all, and to do a *comprehensive* analysis of the entire set. Beyond that, it's *nothing* but an assumption.

And we haven't even come close to either collecting them all, or having a single database, or doing such a comprehensive analysis. Sure, they *might* be unique, but we don't know, and the people saying so (mostly law enforcement) have a vested interest in it being true.

It may be more reliable than, cough, a polygraph, but it's *hardly* a sure thing.

Not even close, given the current state of research.

Too much CSI and the like has tainted our expectations.

Thankfully, it's just one piece of the puzzle.

Like eyewitness testimony, it's seems like it would be reliable, but it definitely is not.