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Scientists Wonder What Fingerprints Are For
Hugh Pickens writes "The BBC reports that scientists say they have disproved the theory that fingerprints improve grip by increasing friction between people's fingers and the surface they are holding. Dr Roland Ennos designed a machine which enabled him to measure the amount of friction generated by a fingerprint when it was in contact with an acrylic glass at varying levels of pressure. The results showed that friction levels increased by a much smaller amount than had been anticipated, debunking the hypothesis that fingerprints provide an improved grip. Ennos believes that fingerprints may have evolved to grip onto rough surfaces, like tree bark; the ridges may allow our skin to stretch and deform more easily, protecting it from damage; or they may allow water trapped between our finger pads and the surface to drain away and improve surface contact in wet conditions. Other researchers have suggested that the ridges could increase our fingerpads' touch sensitivity."
nt
Huh? First post? No no no, Finger Prints!
To be there in the case of confusion of identity. They were placed there by our Pleidian Overlords.
This is a fairly true statement however very limiting.
And in the end, the love you take is equal to the love you make
I noticed this at the zoo watching a bunch of monkeys swing from branch the branch in a cage. The tree branches they had been given had been worn smooth through long use and every time a monkey grabbed on to a smooth branch I felt a jab in my fingers in sympathy. There is something bad about grabbing a smooth object and relying on it to save your life.
So maybe finger prints improve grip with smooth timber surfaces. Testing against glass doesn't sound very realistic. We didn't evolve to grip glass. Or maybe (as the summary suggests) it is something to do with detecting the texture of a surface to find a place to grip.
Of course they don't ask why people have unique finger prints. Maybe it evolved to make murderers easier to catch.
http://michaelsmith.id.au
Just one more thing science can't answer. Of course the answer is obvious but no scientist would ever consider [i]that[/i].
It's obvious fingerprints were designed by our creator to help the Police catch murderers.
I also love how they never counterweight their centrifuges.
If it takes an equal amount of resources for the body to grow a finger without fingerprints then it makes sense that they not meant for anything. Not everything has to have a purpose.
Sounds about right. Such micro-ridges, I think, WOULD increase grip on rougher surfaces, which is what we would run into in daily life. Also, if those ridges - generally the top layer of skin - would rip off or shred, the damage done to the hand would be less than were it smooth, I would guess. IOW, maybe a safety feature?
A positive attitude may not solve all your problems, but it will annoy enough people to make it well worth the effort.
It's more likely for something used this much to have functional features than not. Fingers and claws have been around for quite a while. It's hard to imagine them not evolving useful properties. Of course, this can go too far. Try peeling a gecko from a wall, you need to call the Hulk to help.
A positive attitude may not solve all your problems, but it will annoy enough people to make it well worth the effort.
They're for US immigration to scan. Other than that they serve no other purpose, like wasps.
Seriously though, did you know that identical twins have different fingerprints? Not so identical after all.
Summation 2
you idiot!
Then we invented lube
They use auto-balancing centrifuges.
Wanna fight ? Bend over, stick your head up your ass, and fight for air.
Sorry.
I'll get my coat.
In a survey of 100 programmers, 111111 thought that duck-typing was a good idea.
There is a fair amount of evidence that they increase tactile sensitivity. We have nerves that are sensitive to specific vibrational frequencies. As fingerprints run over edges, then generate vibrations at frequencies we have maximal sensitivity for.
http://www.sciencemag.org/cgi/content/abstract/323/5920/1503
...to suppress the knowledge of a designer, particularly with such a stupid idea as evolution!
Maybe they work like treads on car tires... let there be someplace for liquids to move *away* from to improve grip. Or, maybe having "with oil" and "without oil" surfaces that can be selected by varying grip allows gripping different types of surfaces.
Also, grip isn't the only thing hands do. Wiping or scrubbing with your fingers requires some level of abrasiveness.
I suspect that there may be a connection between building calluses and having prints. Possibly, prints are just the way we make "tough" skin that is more resistant to injury.
"Other researchers have suggested that the ridges could increase our fingerpads' touch sensitivity."
:/)
from TFA (sorry i can figure out how to use the quote function
how is this not obvious? where he have some sort of ridge like pattern (hands, feet) we have more sensitive nerves there. The ridges increase surface area of our skin which means we can feel more using up less volume
the star nosed mole is the perfect example of increased surface area for more touch sensitivity.
Makes me want to stab you.
Of course they don't ask why people have unique finger prints. Maybe it evolved to make murderers easier to catch.
I would guess that the only question is why at all do we have finger prints. The uniqueness would then be expected since it would be much more complicated for a system giving rise to same print for everyone to evolve. Start with a system that produces finger prints (for whatever reason), and the usual error while copying the genetic code would certainly make sure that people get unique finger prints.
Is not a city in China.
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
The USA's National Public Radio show, "Science Friday" discussed this:
http://www.npr.org/templates/story/story.php?storyId=105310429&ft=1&f=5
The show talks about this result, and reveals that New world monkeys have similarly ridged
skin on the gripping side of their tails. Touch sensitivity, and resistance to blistering are
posited as potential answers.
More grip, larger surface, which means more flexibility, more nerve-endings - more sensitivity, better warmth-exchange, 'folded-up-ness', which means more protection from wounds, easier to clean (like footprints, the mud just falls out), 'little bits that stick out' - meaning more sensitivity again.
Religion is what happens when nature strikes and groupthink goes wrong.
With articles such as this, it's hard to tell whether we're being subjected to bad science or bad journalism. Both the summary and TFA quite categorically state that the "myth" of fingerprints being used to improve grip has been disproven. They then go on to describe how this experiment tested whether fingerprints helped when grasping an extremely smooth surface, and found out that they didn't (well okay, actually they did, but not by very much).
Finally, some alternate hypotheses as to why fingerprints evolved are posited, the first of which is: they may improve grip on rough surfaces. Not acrylic glass or anything, but those other kind of surfaces - you know, the type that actually occur in nature.
I'm pretty sure I don't know much more now than I did before I read the article.
Why do they have to be for something?
Evolution does not forbid random things, that are neither bad nor good for something.
Sometimes, humans try too much, to fit things into the artificial set of meta-rules that they did create, to describe the complex results of more basic and emergent rules. But those meta-rules have their own artifacts, that are not present in the basic rules and therefore are not present in the world. Like there having to be a "reason" for everything. A human concept that should describe causality, but adds something more to it, which does not exist in reality.
Other than that, it is obvious, that they enhance the grip, even in situations with liquids.
Any sufficiently advanced intelligence is indistinguishable from stupidity.
Book 'im Dano.
"My preferred theory is that they allow the skin to deform and thus stop blistering. That is why we get blisters on the smooth parts of our hands and feet and not the ridged areas: our fingerpads, palms and soles."
http://www.manchester.ac.uk/aboutus/news/display/?id=4715
I can't tell you how many times I've been out back, trying to climb up my giant sheet of plexiglass, wondering why I just can't seem to get a good grip.
Now I know! Thank you, "scientists"!
So what? Who is to say they aren't slowly evolving away and they were much more pronounced in the past when we needed it living out in the wild?
Much like an appendix, its most likely something once useful that is on the way out. Evolution doesn't happen overnight.
---- Booth was a patriot ----
I am going to go with...They are for increasing touch sensations on the fingertips to increase detection of differences and variations in textures of objects.
Celestial barcodes. The gods are thinking of moving towards an RFID based solution but for now it works.
Humans are the only species who regularly consume large amounts of ice-cold beer. Fingerprints enhance the displacement of water, providing a firmer grip and thus increased consumption and less spillage. I for one am exceedingly thankful and have left my prints on cans and bottles throughout this world.
I'm guessing that there probably wasn't a whole lot of acrylic around during the evolutionary period when fingerprints developed.
Isn't this the same question as why we have 5 fingers on each hand instead of 4 or 6?
Evolution won't remove/change features if it isn't a disadvantage for the survival.
So perhaps you have to look at species way before humans and monkeys.
that's the problem i have with evolution. i find it hard to believe that people born with a few extra ridges in their fingertips were so improved that they dominated the species so we all have them. And troll me if you want, but when did a birds body get the intelligence to start growing feathers even though for hundreds of generations the feathers must have been completely useless?
And whats up with the big bang?! Who made that shit up?!
By properly using the subject line to state the subject, and the body to state that which you wish to say.
Fingerprints are for creating jobs for law enforcement, all part of the master plan.
Hope is the currency of fools
Picking your nose seems like a good enough reason.
Some drink at the fountain of knowledge. Others just gargle.
For some reason, when I look at my fingerprints, I think of tree rings. When we were little fetuses still growing fingers, perhaps there was something about how the skin extends itself that causes an oscillation pattern. This would explain why all the ridges curve along the tip of the finger. There are a few major forms of fingerprints that are caused randomly, which may be explained by the environment the hand area was in when the fingers were formed. Maybe whorls are formed when a side of the developing finger was rubbing against something. Arches seem to be the most natural shape, just skin pushing itself out.
Fingerprints might not have any use. There could be a multitude of reasons why people have them. People could find them sexy or fear anyone that doesn't have them. They could simple be a by product of another mutation that benefited humans. Evolution is a fun random thing without any real directional purpose. Some times yes mutations are beneficial other times not. People have a lot of trouble understanding that.
Roland Ennos designed a machine which enabled him to measure the amount of friction generated by a fingerprint when it was in contact with an acrylic glass at varying levels of pressure.
Acrylic glass. Now that sounds like something primates would be gripping thousands of years ago!
The results showed that friction levels increased by a much smaller amount than had been anticipated, debunking the hypothesis that fingerprints provide an improved grip. Ennos believes that fingerprints may have evolved to grip onto rough surfaces...
This proves that fingerprints do not improve grip... instead we hypothesize that they might be evolved to improve grip. Really? *shakes head*
Perhaps they helped attract mates?
So was this a test to determine if we've developed a characteristic through millions of years of evolution that allows us to grip acrylic glass better? Last time I checked, how well something grips depends considerably on what is being gripped. I doubt there was much natural selection for the ability to grip "acrylic glass." Now, if they'd tested for grip on tree bark while swinging they might be on to something ...
I lose my fingerprints from time to time due to a skin condition, and I drop things a lot more when they're not there. While that's anecdotal and lacks a lot of scientific rigor, I'm not inclined to discard the idea that they're there to improve grip.
I'm trying to teach myself to set people on fire with my mind... Is it hot in here?
Why do they vary so much? Aside from a few mutations and birth defects, we all have 2 arms, 2 legs, 10 fingers, etc. Even if they don't serve a purpose, why does everyone have different fingerprints?
Fingerprints are for nothing. Fingerprints are a byproduct of the processes necessary for the production of new cell growth.
Fingerprints are the md5sum of our DNA code.
Theists are always using the wrong arguments when the try to disprove atheists. They're all about how well bananas fit in the hand and whatnot. That kind of stuff is easily explained by evolution.
Now this, on the other hand, is a good argument. We're all equipped with unique signatures for easy identification, and not only that. We leave a trail where ever we've been so we can be tracked using the same unique identifiers. They provide no apparent benefit, the identification/tracking part can clearly not be attributed to evolution since we figured out how to use it only a couple of thousand years ago.
Now why do we have unique identifiers that also allows us to be tracked easily?
I'm an atheist, but this is the kind of stuff that makes the debate interesting. ;)
(I guess it's a "good" argument for intelligent design, but not really for an omnipotent, omniscient deity)
I imagine fingerprints are just the way the cells happen to divide and the unique pattern is just the result of random growth.
It's like if you look at the back of your had, you see slight lines everywhere, that makes your skin look like scales. It serves no purpose; it is an artefact of growth.
This is an armchair theory though.
Slashdot needs Geekcode | Can anyone recommend any good SCIFI? My tastes: Foundation, Startide Rising, CITY, Ringworld,
Our original alien creators gave us fingerprints for identification purposes. Just because we had lost that information before we regained it, doesn't change anything. It is for ID purposes...
They are there to make it easy for our Fingerprint-taking Overlords to monitor and control us
In Related News
The Beauty industry say that regardless of functionality, they will soon develop fingerprint smoothing hand cream; to go with pore-less look foundation. Soon you will be able to say goodbye to unsightly fingerprints.
Creationists say they are not surprised and that God gave us fingerprints because he wanted right wing governments to be able to keep track of unbelievers better. They note that no angel has ever been known to have finger-prints.
Palm readers everywhere say that this truth had already been revealed to them through years of study. Sceptics countered that it is easy to say that after the study has been released.
Conservation of angular momentum makes the world go round.
They are there as a tag system so that our alien slave masters can register their property. Don't everyone know that?
Odd how they neglect to remember that the dermal papillae also serve to expose more epithelial tissue to the blood supply easier. Did they forget to read their High School Anatomy book?
How do you know there's not using an auto-balancing centrifuge? I mean, I don't watch the show myself, so maybe I'm way off base, but it sounds like a dumb complaint to me.
Comment of the year
The "faith" of an atheist is not the same as the faith of a theist. You're conflating two different uses of the word. I have faith that there is no god in exactly the same way that I have faith that there is no Flying Spaghetti Monster, or that I have faith that Russel's teapot does not, in fact, exist. If you want to call that "faith," it's within the boundaries of English usage, but it's an entirely different faith than positive faith in a particular god. And you clearly have no clue about scientific evidence. The default position is we assume things do not exist unless we are presented with positive evidence to the contrary. It's the theists who have the burden of proof, not the atheists. To this point, the theists have failed spectacularly.
Because there is so much other evidence to show that fingerprints do help. The stupidest example is rubber gloves. Rubber gloves are often made with an increased surface area about the finger tips to help in gripping, and I think there are those who have had burns and stuff on their hands where their fingerprints are gone also have a harder time of gripping.
This is my sig.
Obviously the aliens who seeded our planet millions of years ago wanted some way to identify which strains eventually became most successful.
That's because the original 512 genetic strains dumped on our planet were created as part of a lottery...so there's a lot of cold stinky alien cash riding on the results of this seeding.
My research shows they are arriving around 03:14:07 January 19, 2038 UTC to perform the final census.
Occam's razor should be applied in these situations so people don't run off on odd whimsical tangents. This is all so obvious when you stop and take the time to ponder it.
i believe it provides protection against minor cuts, an alternative to thick skin. And provided feedback in assessing textures.
NOT. Maybe they can prove what their asses are for.
Look at which other species have fingerprints.
Is it just apes?
Do dogs/cats have individual paw prints?
Do Horses have hoof prints?
Do the tip of our nails have nailprints that would distinguish them if we looked close enough?
Do octopus suckers have fingerprints?
It could just be background noise.
They could be vestigial.
They could be an echo of the growth process since they are on the tips of our fingers and toes.
Would we find similar swirly distortions on the tips of dog tails, fish flukes?
She was like chocolate when she drank... semi-sweet at first and then increasingly bitter.
I mean, these are just theories that you and I could come up with in a brainstorm session.
I agree with the multiple reasons - e.g. better grip over rougher surfaces.
But maybe the ridges also allow you to more easily detect that you are losing your grip (sliding) while still allowing the skin to be/grow thicker (calluses) and more resistant to wear and tear.
Should be quite important to most primates to detect that they are losing their grip on stuff.
Slippage-detection might even be more important than having better grip in the first place. Since you can often increase grip by increasing the force. e.g. "Uh oh, I'm slipping, better hold on tighter - and look for something else to grab on, quick!".
It's so Xenu knows who is who!
IIRC, there was an article on either Slashdot or Arstechnica where evidence was presented that at least one real role of fingerprints is to increase tactile sensitivity.
Bureaucracy expands to meet the needs of the expanding bureaucracy.-Oscar Wilde
I've had the experience of having no fingerprints for a time. I worked at UPS unloading trucks; one of the customers shipped many thousands of small boxes just before the end of the year; the boxes were the precise size that the only way to grip them was with the pads of fingers and thumb (I'm looking at you, Daytimers!). A large portion of those boxes passed through my hands. Shortly after I started work there, I noticed that I was having trouble gripping items that were wet - a water glass with condensation on it would routinely slip through my fingers. When I examined my hands I saw that the ridges of my fingerprints were basically worn away. I wore gloves for a bit while working and the problem cleared itself up.
Another illustration would be to look at the skiving on the bottom of a pair of deck shoes. On a dry surface, they offer no advantage whatsoever, but on a wet surface the difference in grip is remarkable. Or for that matter tire treads - a set of slicks is the absolute best way to maximize grip - unless it's wet, at which point they become the WORST configuration.
"As God is my witness, I thought turkeys could fly." A. Carlson
Despite the advances made in evolutionary science, there still persists this belief that everything has a reason. This is a legacy meme from ancient religions and schools of philosophy. Everything does NOT need to have a teleological cause. It might be that fingerprints developed because they rendered some advantage, or it might be that they happened randomly, and persisted because they did not cause a disadvantage. You're scientists, so quit with the magical thinking.
Dogs have noseprints that are as unique as fingerprints (and in fact are legal ID for dogs in Canada).
Uh... why exactly is Canada defining legal and illegal ways of identifying dogs?
Actually, as a scientifically-minded agnostic, I have to agree that atheism is definitely a religion.
We really do lack sufficient evidence to comment on the existence of entities powerful enough to be called gods, who could potentially do things like create planets or influence evolution in a specific direction. In fact, given how vast the universe is, I'd even have to bet that something like that is out there somewhere. (Of course, true omnipotence or omniscience are quite impossible.)
Now, non-circular evidence for the existence of the gods of the religions of Earth is non-existent. All signs point to the fact that they are ideas created by men to control other men. It can be argued whether this was conscious pre-meditated intent by a few specific individuals or just an aggregate effect of collective ignorance and natural opportunistic tendencies, but the end result is the same.
Knowledge != Intelligence
Or maybe it didn't evolve that way for any particular reason.
The fact that fingerprints are so conserved among primates, and some even have them on their tails which they use to grip trees as well, to me that suggests it's a functional feature. Were humans the only ones with fingerprints I would agree that it might not be an evolved feature.
We use fingerprints for identifying criminals, but clearly that's not what they were evolved for. In the absence of the conservation, had the friction studies shown a positive result, that still would not have meant it was evolved for that purpose. But the fact that primates have kept fingerprints around through multiple speciation events really makes it seem like it had some function. There's also the possibility that it is somehow necessary to develop fingerprints in order to develop primate fingers.
Some things just don't have a purpose. This study is just about as stupid as asking, "Why is water wet?" --- It is what it is. Perhaps, the better question is, "Why do we have skin?" but we all know the answer to that. Prints are just another outcome without reason.
If I want better grip, I where those sticky rubber work gloves. Has our brain power negated all bodily evolution?
-=[ place
"Other researchers have suggested that the ridges could increase our fingerpads' touch sensitivity."
Yeah, because we knew back then how we would control the cursor on our laptops.
Since we were genetically engineered by an extraterrestrial civilization they designed fingerprints in our DNA so that they could catalog us for later use.
Man, look at the fingerprints on her!
http://ethomas.web.wesleyan.edu/wescourses/2004s/ees227/01/spandrels.html
"The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the Adaptationist Programme
Stephen Jay Gould and Richard C. Lewontin
Republished from the original with the kind permission of The Royal Society of London: Gould, S. J. And Lewontin, R. C., "The Spandrels of San Marco and the Panglossian Paradigm: A Critique Of The Adaptationist Programme," Proceedings Of The Royal Society of London, Series B, Vol. 205, No. 1161 (1979), Pp. 581-598.
An adaptationist programme has dominated evolutionary thought in England and the United States during the past forty years. It is based on faith in the power of natural selection as an optimizing agent. It proceeds by breaking an organism into unitary "traits" and proposing an adaptive story for each considered separately. Trade-offs among competing selective demands exert the only brake upon perfection; non-optimality is thereby rendered as a result of adaptation as well. We criticize this approach and attempt to reassert a competing notion (long popular in continental Europe) that organisms must be analyzed as integrated wholes, with BauplÃne so constrained by phyletic heritage, pathways of development, and general architecture that the constraints themselves become more interesting and more important in delimiting pathways of change than the selective force that may mediate change when it occurs. We fault the adaptationist programme for its failure to distinguish current utility from reasons for origin (male tyrannosaurs may have used their diminutive front legs to titillate female partners, but this will not explain why they got so small); for its unwillingness to consider alternatives to adaptive stories; for its reliance upon plausibility alone as a criterion for accepting speculative tales; and for its failure to consider adequately such competing themes as random fixation of alleles, production of non-adaptive structures by developmental correlation with selected features (allometry, pleiotropy, material compensation, mechanically forced correlation), the separability of adaptation and selection, multiple adaptive peaks, and current utility as an epiphenomenon of nonadaptive structures. We support darwin's own pluralistic approach to identifying the agents of evolutionary change.
1. Introduction
The great central dome of St. Mark's Cathedral in Venice presents in its mosaic design a detailed iconography expressing the mainstays of Christian faith. Three circles of figures radiate out from a central image of Christ: angels, disciples, and virtues. Each circle is divided into quadrants, even though the dome itself is radially symmetrical in structure. Each quadrant meets one of the four spandrels in the arches below the dome. Spandrels-the tapering triangular spaces formed by the intersection of two rounded arches at right angles are necessary architectural byproducts of mounting a dome on rounded arches. Each spandrel contains a design admirably fitted into its tapering space. An evangelist sits in the upper part flanked by the heavenly cities. Below, a man representing one of the four biblical rivers (Tigris, Euphrates, Indus, and Nile) pours water from a pitcher in the narrowing space below his feet.
(this image at www.bun.kyoto-u.ac.jp/ ~suchii/spandrel.html)
The design is so elaborate, harmonious, and purposeful that we are tempted to view it as the starting point of any analysis, as the cause in some sense of the surrounding architecture. But this would invert the proper path of analysis. The system begins with an architectural constraint: the necessary four spandrels and their tapering triangular form. They provide a space in which the mosaicists worked; they set the quadripartite symmetry of the dome above.
Such architectural constraints abound, and we find them easy to understand because we do not impose our biological biases upon them. Every fan-vaulted ceiling must have a series of open spaces along the midline of the va
Just a tip: we speak HTML here. We don't look kindly on outsiders coming in here and speaking BBCode.
Sounds rather hostile there .. .. ...
I didn't see a sign BBCODE gets frowned upon
We did understand him/her, let's just hope he/she will find out html tags soon
Else [F][i][d][o], the new pup around the block would already have eaten them up! The user*euh*BBcodes I mean .. you know?
on another note: I wish [F][i][d][o] could sniff out these slashdot bugs buggering my firefox all over ...
--- I am known for the ones who want to find me on the net. Is that a privacy risk or a privilege? One might wonder..
I can't believe it when I see articles debating the purpose of fingerprints. They are mechanical amplifiers for vibration in the skin, thus enhancing touch perception; it's been known for 50-70 years that the ridges form a specific arrangement with the sensory fibre endings. In fact the ridges are CREATED by interactions between the developing skin and the nerve fibres which innervate it to provide touch sensation - this is why some nervous system defects result in abnormal fingerprints (e.g. Down syndrome). The only "Scientists [who] Wonder What Fingerprints Are For" are those unaware of the basic literature in the field. Here's a starting point: http://stke.sciencemag.org/cgi/content/abstract/sci;323/5920/1503 Hope that helps.
If a textured surface doesn't increase traction, why do they bother putting treads on tires? Wouldn't smooth tires work just as well?
There are animals that have very few offspring, but for several reasons are very good at defending them.
Quantity only works where the quality of the parenting is relatively poor (fish, insects, etc).
IANAL but write like a drunk one.
Humanity was created by aliens literally more than dozens of years ago. When this happened, they wanted to be able to distinguish between two people without doing a DNA scan, since all you - er, us humans look alike. So the aliens engineered us to have these useless fingerprints.
And they also have lab techs performing interrogations, all of them seem to be happy with their hair in their face while they're searching for fibers on a mattress or gathering evidence from a crime scene.
What a waste of a study if you didn't include toe prints. Who picks up a glass with their feet except my ape masters.
Not to be crass, but this is one of those situations where differential reproductive success directly impacts the evolution of a trait - the scientists should have tested it on the hair and skin on the backs and sides of female primates and/or whatever surface female primates grab onto while 'making sweet sweet love'. No grip, no offspring. Branches? Acrylic? What? Whatever.
I take issue with the folks that ask why do fingerprints have to do anything. Even if they were ever a "neutral" mutation. Nature has an insidious habit of stumbling into situations where they do provide a benefit. They have been preserved, even have flourished. We have them and we will find more uses for them. It's like "junk" DNA. If we ask the right question we find this stuff that does not transcribe still plays an important role in the way genes are expressed.
This is not as simple as it sounds. 'Mutation' can mean any of a very large number of kinds of changes to DNA. IAAEB, by the way., so I have to chime in. It almost counts as working.
It's really more accurate to say that most mutations that are kept are *not harmful*. While this may seem like nit-picking, you have to remember that the reason evolutionary theory is hard is that it is based on mathematical models of really complicated processes.
When you express a mathematical model in plain language, you have to be nit-picky or you won't express the real meaning of the model and you can draw false conclusions.
About the only way to say that a physical feature is 'for' some particular purpose is by a lot of experimentation using gene knockouts, breeding experiments or other techniques. Even then, we can't be sure we have found the full evolutionary reason for the feature.
This is the reason most biologists don't have to think about evolutionary theory very much. It is difficult enough to figure out the genetic basis (the functional 'how') for a physical feature let alone try to figure out the evolutionary 'why'. Many a full career can be spent just figuring out the 'how'.
The ridges tilt when there are sideways components of force, resulting in pressure differences between the two sides of each ridge. The skin has only pressure force sensors, no tangential force sensors, so the ridges allow sensing tangential forces without needing some new kind of nerve/sensor system. That is important for gentle gripping, for example, so you can tell when a tighter grip is needed to prevent slipping. So the pressure sums or averages give the total normal force, and the local differences give the tangential components of the force. Useful.
I just took at my body and from head to toe and i see a purpose for every part on me. I'm sure there is a purpose for finger prints. anyways, we do use them for identification, isn't that a purpose? plus imagine if your fingertips were perfectly smooth, you wouldn't be able to feel things in as much detail. I think everything has a reason, we just haven't found out why yet. We act like we know everything yet we can only explain a fraction of the phenomena that goes on in this world not to mention the rest of the universe. others are happy with just saying "oh its random." If everything is random then nothing is random.
I worked in a warehouse for a summer working 70-80 hours a week. I handled cardboard boxes 16-18 hours a day. After the first week my fingertips were worn smooth. I had no fingerprints and I found it more difficult to pick things up. I ended up buying some gloves with little rubber knobs and they helped. My fingerprints grew back and I could pick up boxes again. From them on I wore gloves with some type of gripping aid. They usually only lasted about a week.
The presence of "print" ridges and valleys on the human hand extends to the entire gripping surface and, arguably, a small area just beyond. They clearly have a key role in gripping, touch or both, but I'm not sure how useful it is to show that they don't help much with friction on the sort of overly-smooth surface that rarely occurs naturally.
For what it's worth, mind, my vote is for a "cat's whiskers" sort of sensory function - that having raised ridges increases skin distortion as objects are touched, which in turn increases sensitivity, precision and discrimination in the hand as an organ of touch.
When you hold your hands together and pray, the fingerprints sign the prayer so God knows who it came from. That is why you hold your hands in front of your face in the usual pose. The prayer passes over both hands on it's way to God.
What about my SCROTUM print?
...how does testing fingerprints against fingerprints get us anywhere?
Until they conduct a test comparing the friction of those -with- fingerprints and those -without-, they haven't really tested if fingerprints improve friction or don't.
My fingertips are almost all scarred from eczema as a child, leaving them quite smooth. I would be happy to volunteer in this study. I find I can't seem to hold onto smooth surfaces nearly as easily as others can.
Hmm?
Everyone knows the government made fingerprints to keep tabs on its' citizens.
Something witty.
Nahhh, they're ribbed for ((y)our) pleasure...
Previously: "Linux... Toward the Sunrise..." Now: "Linux... Toward the-- No, now, part of Every Sunrise"
Because humans evolved needing to hold onto acrylic glass? Can anybody name ONE natural substance even remotely like acrylic glass? Come back with a model of how fingerprints affect friction on substances like plant material or rock, then maybe this will be credible...
Obviously God designed them so that we couldn't get away with crimes after 1892.
https://www.eff.org/https-everywhere