A Problem with Evolution?, why haven't we evolved to see in the infrared range? Options

[lucid_dream]

At the outset, let me unequivocally state that I am no fan of creationism or other religious crap myth creation accounts.

But neither am I entirely satisfied with evolution as solely operating through random variation and natural selection, and here's why.

Something that's always troubled me about evolution is, how come we humans don't see in the infrared (IR) frequency range? I mean, all it requires is a slight molecular modification of rhodopsin, and it would confer a big survival advantage on humans possessing the new IR-sensitive rhodopsin since they would be able to see other living things in the dark and at night. So why haven't we evolved to see in the IR spectrum, in addition to the normal visible spectrum?

[Neural]

maybe rhodopsin can't easily be made IR sensitive? I don't know.

[Rick]

The greater survival advantage would be to nocturnal hunters and prey. Still, I know of no animal having IR vision. IR, having longer wavelengths (especially at body temperatures) than visible light, has lower resolution, leading to blurrier images, than with visible light. IR imaging is made possible with electron amplifiers. Perhaps a biological equivalent is not feasible when limited to purely chemical means.

[code buttons]

A good answear could also be, that we never needed that much vision to keep up with our environmental needs. We were too busy developing bigger brains to smart out the night hunters. Now we manufacture night-seeing eyes for our use which far surpass anything nature could ever think of develping here on earth.

[lucid_dream]

maybe we could genetically engineer IR-sensitive humans. I'm guessing there's something about rhodopsin not being IR-sensitive; as Rick noted, there seem to be no animals with IR vision. There's the night-vision of cats, but that requires some light source and is not IR. There's echolocation of dolphins and bats, but that not anything like vision.

[Rick]

Here's another question about evolution: why haven't animals (humans, in particular) evolved photosynthesis? Humans generate melanin in the skin to block sunlight to prevent damage from UV light. It would be very easy, I would think, to genetically engineer skin cells that generated chlorophyl to make sugar from CO2 and sunlight. The green people could go for days without eating in the summertime.

[Trip like I do]

It may be that the evoloutionary scale is already tipped heavily in favour of the human race. Why stop at the IR, as there are many other levels of reality that occur beyond the current capabillities of the human sensorial aperati?

Having these abilities may give humans too much power, power that we as a human race are presently not prepared for and to deal with.

[Dan]

If you had IR vision, how could you block out the IR signals in order to go to sleep?

[rhymer]

Having IR cision would be of benefit in seeing warm blooded threats.
But what walking into trees or falling over cliffs in the dark? Neither normal or IR vision works in worst case scenarios!

[Hey Hey]

Here's another question about evolution: why haven't animals (humans, in particular) evolved photosynthesis? Humans generate melanin in the skin to block sunlight to prevent damage from UV light. It would be very easy, I would think, to genetically engineer skin cells that generated chlorophyl to make sugar from CO2 and sunlight. The green people could go for days without eating in the summertime.

It's all about niches that were/are/might be available to evolve in. Fungi also do not have chlorophyll, having saprophytic, parasitic or symbiotic lifestyles. The diversity of types of organisms is fed on by evolution to meet the requirements of newly emerging niches, habitats, food sources, etc. Too much overlap is bad as it reduces independent diversity, although an organism that overlaps might appear periodically but would then be fed on to provide a fitter type for a given purpose. And, importantly, the most efficient lifestyle is sought and, and excess baggage is (sometime gradually, sometimes rapidly) offloaded.

Another point, possibly related to the above, is that haemoglobin and chlorophyll are quite similar, the former utilising iron, the latter magnesium. Photosynthesis (using chlorophyll) generates oxygen as a by-product; respiration using haemoglobin or some related carrier utilises oxygen that eventually acts as an electron acceptor in cell metabolism. Of course, nature is much more complicated than this. There are anaerobes, that don't photosynthesize or utilise oxygen. And plant cells also respire, using oxygen in the process (but they have a net loss, otherwise we die). And more...... all working together, as does a well designed Simcity! If only!

[OnlyNow]

This is a simplistic answer, but I think the reason we don't have infrared vision is because up to this point, our survival (as a species) hasn't required it. Suppose that at some point along the way, we'd been the prey of a group of creatures with extraordinary night vision. Maybe then, any mutation toward IR vision would have become relevant, as only those individuals so endowed would have survived and procreated. Evolution favors survival only. Extra bells and whistles are lost unless they become necessary for survival.

[code buttons]

So, besides wisdom teeth, what other parts of the present human body are doomed to fall down by the wayside? I understand there's a foot bone that appears only in some of us, which used to be more prominent back in Neardanthal times...

[Hey Hey]

Ladies and under 18's do not read the following. Just in case you do, I apologize in advance.

I understand there's a foot bone that appears only in some of us, which used to be more prominent back in Neardanthal times...

If you had a foot, you'd probably need a bone in it!

[lucid_dream]

besides wisdom teeth, our appendix and our small toes, and I imagine body hair since this is more often an annoyance than anything else.

[code buttons]

I understand there's a foot bone that appears only in some of us, which used to be more prominent back in Neardanthal times...

If you had a foot, you'd probably need a bone in it!

I'm not making this up. A friend of mine was a star quaterback in high school but didn't have too many scholarships offered because he had this extra foot bone. This was several years ago. So, I don't remember the details.

[code buttons]

besides wisdom teeth, our appendix and our small toes, and I imagine body hair since this is more often an annoyance than anything else.

My small toes ain't going nowhere. I figure I bridge them together somehow and make for added propulsion in the water. And right now I'm working hard at the gym on doubling my pecs in size in hopes of picking up some high speed momentary levitation off my bike, or the back of my truck.

[code buttons]

besides wisdom teeth, our appendix and our small toes, and I imagine body hair since this is more often an annoyance than anything else.

My small toes ain't going nowhere. I figure I bridge them together somehow and make for added propulsion in the water. And right now I'm working hard at the gym on doubling my pecs in size in hopes of picking up some high speed momentary levitation off my bike, or the back of my truck. What other muscles besides the obvious triceps, biceps and abs should I work on? Any back muscle in particular?

[Rick]

Instead of exercises that focus on single muscles, try some more general exercises for groups of muscles. For levitation, do bar dips (on parallel bars) and pullups (on a high bar). A person in good general condition should be able to do 15 bar dips and 10 pullups (all the way up and all the way down slowly).

[Trip like I do]

Extra bells and whistles are lost unless they become necessary for survival.

....I truely appreciate and thourogly enjoy all of those bells and whistels of reality!

[OnlyNow]

Extra bells and whistles are lost unless they become necessary for survival.

....I truely appreciate and thourogly enjoy all of those bells and whistels of reality!

Exactly how does one trip like you? Real-ly.

[OnlyNow]

besides wisdom teeth, our appendix and our small toes, and I imagine body hair since this is more often an annoyance than anything else.

This reminds me of something I've wondered about, since like, forever. Thank God I've found a forum in which somebody surely has the answer...

Why did we evolve to lose nearly all the hair on our human bodies, only to choose to cover them up with clothes?

The very fact that we wear clothes, that we MUST wear clothes is something that most people never stop to ponder. To my knowledge, there are no other species that have this hangup characteristic.

Why do we wear them? Yes, it makes sense that we need extra covering for protection and extremes in weather, but that's not what I'm talking about. I'm talking about the fact that nearly every single one of us virtually always wears clothing--even when indoors or in temperate climates. In fact, I'd almost say that wearing clothes is one of the things that makes us human--right up there with language and...the other things.

It almost seems that the basic point of clothing (beyond utilitarian) is to cover up our bodies from view of others. Whenever we do take our clothes off, we simply cannot let anyone else see us--not even for a second. Why is that? Being seen totally naked is almost a fate worse than death. I remember having a discussion with coworkers concerning how much money it would take for any of us to walk through the office and then across a busy street--totally in the buff. The amount varied by person, of course. (Some of the men claimed they'd do it for $10. Maybe I would have done it for $10,000...but when it came right down to it, I don't know.) My point is, almost universally, total nudity is totally taboo. WHY??? How did that all start? And why must the genitals in particular remain covered? Our fanatic requirement to cover our private parts is absurd! Nobody knows what anyone else even looks like naked, not even closest friends or family members.

Of course, there are a few very important exceptions to the clothing-at-all-times rule. I wonder if sex and procreation somehow benefits, ironically, by the fact that we otherwise keep certain things under wraps.

Answers?

[Trip like I do]

Extra bells and whistles are lost unless they become necessary for survival.

....I truely appreciate and thourogly enjoy all of those bells and whistels of reality!

Exactly how does one trip like you? Real-ly.

I would begin by thinking about 'rhizomes'....

[Neural]

about clothing, I don't know about all of you but I certainly wouldn't want a naked guy who just got off the can to sit anywhere near me, much less on my sofa or other furniture.

I think the clothing issue comes down to maintaining our privacy and offers some protection against the elements. For instance, I find it hard to walk around indoors without a shirt on for long periods because I'm sensitive to air currents on my skin.

[code buttons]

The very fact that we wear clothes, that we MUST wear clothes is something that most people never stop to ponder. To my knowledge, there are no other species that have this hangup characteristic.

Why do we wear them?

I think that fellow Adam really screwed us all up when he started listening to Eve; causing us all to lose our innocense. If it wasn't for him we would be spending a lot less money on materialistic things and maybe investing it better feeding the hungry or some worthy cause like that.

[Rick]

Why did we evolve to lose nearly all the hair on our human bodies, only to choose to cover them up with clothes?

There are several theories of human body hair loss that I know of. One is that we lost our hair to make it easier to control fleas. Another is that humans spent some time in our evolutionary history in a semi-aquatic state, and hair loss made it easier to move in the water. Another theory is that we evolved sweat cooling to allow extended periods of high exertion, and nakedness promotes evaporation. None of these theories is fully convincing, so the definitive answer is not yet available. For a treatment of this and other topics of human evolution see (the somewhat old now) book The Naked Ape by Desmond Morris.

For a fictional treatment of a subculture of casual nudity, read Stranger in a Strange Land by Robert Heinlein.

The state of personal sensitivity to nudity is cultural and occasional. The first time a person appears in a swim suit in the warm season may seem a little awkward, but by August (in the northern hemisphere) he or she may be walking into beach stores with just a swim suit on. I have been to nude beaches and with groups of friends to nude swims at mountain streams with little or no embarrassment. It just depends on which subculture(s) one is participating in.

[Trip like I do]

I wonder why hair has only remained in certain (strategic?) areas? And what are the evolutionary advantages of hair remaining in those transhuman regions?

[Trip like I do]

Extra bells and whistles are lost unless they become necessary for survival.

....I truely appreciate and thourogly enjoy all of those bells and whistels of reality!

Exactly how does one trip like you? Real-ly.

I would begin by thinking about 'rhizomes'....

Deleuze' & Guattari's concept of the rhizome....from wikpedia

Gilles Deleuze and Félix Guattari used the term "rhizome" to describe theory and research that allows for multiple, non-hierarchical entry and exit points in data representation and interpretation. In A Thousand Plateaus, they opposed it to an arborescent conception of knowledge, which worked with dualist categories and binary choices. A rhizome works with horizontal and trans-species connections, while an arborescent model works with vertical and linear connections. Their use of the "orchid and the wasp" was taken from the biological concept of mutualism, in which two different species interact together to form a multiplicity (i.e. a unity that is multiple in itself). Horizontal gene transfer may even be observed, challenging the traditional evolutionist theory.

Carl Jung's metaphor of the rhizome

Carl Jung used the term "rhizome", also calling it a "myzel", to emphasize the invisible and underground nature of life:

Life has always seemed to me like a plant that lives on its rhizome. Its true life is invisible, hidden in the rhizome. The part that appears above the ground lasts only a single summer. Then it withers away—an ephemeral apparition. When we think of the unending growth and decay of life and civilizations, we cannot escape the impression of absolute nullity. Yet I have never lost the sense of something that lives and endures beneath the eternal flux. What we see is blossom, which passes. The rhizome remains. (Prologue from "Memories, Dreams, Reflections")

[Hey Hey]

Hair under the arms and in the groin serves to lubricate those regions, where there is close moving contact between skin and skin, amongst other things. In an upright creature the head and shoulders takes the brunt of the sun, hence long hair over the shoulders and back and bearded face (in males; OK why not in females?). (Now fashion often requires the removal). Eyebrows divert rain away from the eyes, eyelashes similarly and additionally help to filter the air and bright light when we squint. Nose hair filters the air. I can't think of the reason for that single hair on my wife big toe but it always raises a laugh when she plucks it and then goes hopping around until the pain subsides. And why doesn't the exterior of the nose have hair? It is very susceptible to rodent ulcers and other skin cancers.

[OnlyNow]

Okay Trip, I've been thinking about rhizomes all day. Now what?

[OnlyNow]

Hair under the arms and in the groin serves to lubricate those regions, where there is close moving contact between skin and skin, amongst other things.

Then I wonder why we don't have hair between our fingers and toes.

In an upright creature the head and shoulders takes the brunt of the sun, hence long hair over the shoulders and back and bearded face (in males; OK why not in females?). (Now fashion often requires the removal).

This makes sense, though I wonder why hair doesn't grow on top of our shoulder skin for protection against the sun. And yeah, how come women don't have hair on their faces?

Eyebrows divert rain away from the eyes, eyelashes similarly and additionally help to filter the air and bright light when we squint. Nose hair filters the air.

Makes sense.

I can't think of the reason for that single hair on my wife big toe but it always raises a laugh when she plucks it and then goes hopping around until the pain subsides. And why doesn't the exterior of the nose have hair? It is very susceptible to rodent ulcers and other skin cancers.

She's lucky there's only one. Good point about the exterior nose. It seems to sunburn the worst.


It almost seems that some of this hair growth is random, arbitrary and pointless. I guess it doesn't all have to "make sense," but it would be nice if it did.

Rick, that's great, and why am I not surprised that you occasionally frolic in the nude with friends. I myself participated at a topless beach one time--for about five minutes. There are probably a quite a number of people who spend a lot of time in the nude. But that doesn't answer my basic question. What's the point of modesty and why is it so fervently ingrained into most cultures? Why would anyone even come up with the idea that displaying certain body parts in public is an extreme no-no? Even if someone decided this would make sense (and apparently, someone did), or even if the whole thing evolved slowly, how did the concept catch fire--to the point that it's so ingrained into our humanity that "everyone" does it and nobody knows (or asks) why?