Thoughts on the Humanoid Form

[Jennifer Diane Reitz]

I've been thinking about UFO stuff lately, and researching it because it fascinates me. There is a lot of crap out there, and as wild as most of it is, there is, deep in the most conspiracy-oriented stuff, an astonishing degree of agreement and consensus - but I am not here to argue these matters.

Rather I am here to explore one aspect of the matter; that essentially -all- reported extraterrestrials are humanoid. No tripods, no space squids, no truly weird monsters in the deep, supposedly real stuff, just humanoids. According to sources such as the famous former Canadian Defence Minister Paul Hellyer http://www.youtube.com/watch?v=RGyFWyNuF3s (and many, many other retired heads of security in assorted governments around the world), some 56-57 different species... all humanoids.

And this is a problem, supposedly, for scientists working covertly with the world's governments in dealing with all this stuff; they can't explain why the human form is universal. Supposedly it shouldn't be. Evolution should take any imaginable form.

I disagree, sadly.

Indeed, after much consideration, I am unhappy to come to the conclusion that our (specifically our) universe will be filled only with intelligent, biological, technological beings that pretty much look just like us. Two legs, two arms, one head, one mouth, two eyes, nose, two ears all on the single head, no surprises. Oh, maybe their nose will be slits, or maybe their eyes will be big or small, or maybe the number of fingers will be more or less than ours, but basically, just like us.

And this will be true regardless of how their species started. Insectoid, animalistic, amphibian, aquatic creature, avian... doesn't matter.

They will all end up just like us. Not even a tail. Boringly, horribly just. Like. Us.

Why?

Economics. The economics of energy.

Every body part costs calories... energy to run. That energy could come from sugars, like ours, or from some other molecule, it doesn't matter a bit. If they need to eat, anything, then they have an energy budget. As long as that energy budget is chemical (they are not atomic/electric/whatever-powered machines -which truly could take any form) there is a limit as to how much energy they can get from the star they must evolve under, and the equivalent of plants and other animals they must eat, and the entropic loss incurred from being downstream of the source, so to speak.

It costs a lot of energy to run flesh, whatever the form. Food must be converted into what the body can use, and that food must be gathered, and it must be prepared, and it must be digested. There is always massive waste, there are limits.

We cannot have tails (sorry Furry fans!) because a tail costs a lot of energy. A tail can cost as much as an extra arm or leg, and that is a lot of food to a proto-caveman, still subject to -natural- evolution in the wild. Unless there is a severely important reason to have a tail, something life-and-death, and not just display, then the tail-less will always survive better, and need less food. They will do much better in the common times of starvation.

A single arm and hand can represent everything a tail can convey, and then ten times more. If a tail can do sign language, that tail is an arm and hand.

Our brains, our intelligence, costs a third of our caloric intake. A third of our entire energy budget goes just to powering our brains. In the wild, prior to agriculture, hunt and gather, hunger is a usual state. Just squeeking by most of the time. Since calories are a set budget in terms of what any such group can generally gather, something has to give to afford that evolutionary brain upgrade. Only so many 'dollars' and every body feature and part costs a percentage of the maximum caloric intake. A human level brain takes one third. Not much left for tails - not if one needs to still walk, carry objects, and be able to hunt and gather. Vision alone takes 20% just by itself, part of that in the brain calculation, but still. So, no, three and more eyes are out.

Blind cave fish are blind not because it is dark in caves. They swam in, originally, as a species with eyes. Eyes are expensive, and food is scarce in the desert of a cave environment. Something had to give. Eyes cost, and in the dark they are useless. Fish without eyes don't need as much food to live, so the dominate.

What is the minimum functional shape for a biological species capable of technology such as starflight?

Two eyes, for stereo vision. Permits accurate interpretation of 3D space, very needed. Three eyes don't add anything. The eyes need to be arranged horizontally, because all animals live walking on the ground. Two eyes horizontal permits the widest view in the most important directions: front and sides.

The mouth has to be below the eyes. Mouths are messy, and there will be no biology without the equivalent of microorganisms, without rot and decay to break down dead things. Eyes are by nature delicate structures, and to see they must not be obscured, and they must be healthy. Food dribbling into eyes is a vast disadvantage in countless ways, from infection to being predator bait. So eyes above mouth, just like us.

The nose has to be close to the mouth. Taste and smell are partners, and both derive from direct, physical experience of molecules. Even ants, who have their taste and smell on their antenna, still have those antenna on their head, so jointed that they can contact the mandibles, and the area in front of the mandibles. But in a large creature, large enough to have a human-level brain, such antenna would cost as much as thin arms. Too much. So taste and smell have to be internal, and close to the mouth. As simple, direct, and cost efficient as possible. Taste and smell exist primarily to allow a creature to eat useful food and avoid poison; other uses are secondary.

Eyes, nose, mouth, tongue. Ears. Two of them, for stereo hearing. Needed to locate sounds in 3D space. No point to hear if you cannot tell where the threat, or the benefit, is coming from. Three ears is overkill.

The ears have to be on the sides of something, separated. Too close and no stereo.

All these senses need to be on a mobile platform... a head. Which can be extended, poked around a corner, laid low to the ground, or raised high to see and hear at distance. Separate stalks for each sense costs as more arms or legs, so no dice. One platform, a head.

Just like us.

On a neck, above the body, because the sensory platform needs to be mobile, as high as calories permit to see and smell and hear far as well as near, and to keep it out of the way of the necessary two, no more than two, arms.

With hands. Of some form. One arm isn't enough to do work. Opposition is the key to useful work... opposing thumb, opposing hands, opposing limbs. To grab, hold, lift and carry. To build and to adjust either in crude, or delicate ways. Three is extra cost for no real benefit. Two is the minimum to do the job, so two is the most efficient.

Legs. Two again. Because that is the minimum needed to walk, to move. Sure, three might be more stable, but it's unnecessary. Four is overkill, the calories for the extra centaur action are needed to power the arms. Centaurs are energy inefficient. Two arms, two legs is enough to do everything and anything, and nature is always a frugal bitch.

Can't have the body below the legs, that's inefficient; too wide a stride, no advantage, more cost in leg length wasted as they run past the body on down. If the creature walks on it's hands, then those arms are legs. Arms have to be free, and separate, to carry anything. Things must be carried, if anything is to be built or constructed.

A waist is not strictly necessary, but it is a huge advantage, for the same reason that a neck is advantageous: spot rotational motion costs less than having to rotate the mass of the entire being. When walking the ancient world, proto-caveman is going to need to scan the horizon for threats, especially when carrying something (which slows one down). This would be the same on any world, in any galaxy, anywhere in our cosmos.

It's the law. Or more specifically, it's the laws of physics. Function, form, minimum caloric intake.

So, Star Trek is right. All the aliens will be humans with funny foreheads. More or less.

Oh, some might be Grays, with four mutually opposed digits, short, thin forms, and large light-gathering eyes, but that is still very humanoid.

Consider the classic Gray alien. It is like the Ideal of the minimalist humanoid form. Every part is the minimum, stripped down necessity, devoid of any fancy details or flourishes. Like hair, or large features, or any other animal fanciness. They are like some kind of minimalist version of Man.

No wonder a common notion of them is that they are artificial biological robots, constructed for maximum efficiency. They have no evolutionary remains to them. Nothing left of nature, just the lowest common denominator of the humanoid form.

But, sadly, all creatures would become that minimum, in time. Along the way, they will be... us.

Evolved fox? Sorry, just another humanoid, not even a fox-like head. That jawline costs, and there is no reason for it in a creature that has hands to snatch with instead of relying on jaws. Flat faces, small noses, small ears. The fur would go, just like on us, for the same reasons. Pointless, and costly. They would be us, just with a different family tree. Maybe any hair left on their head would be red. Maybe. Boringly ordinary, even that.

Same with the evolved dinosaur, evolved cat, dog, whatever. In the end, all will evolve to the common denominator, the minimalist humanoid form. The efficient form.

And such would be the case with any weird planet one can think of. Because all have gravity, and air, and water (or the equivalent, depending on biology... liquid in any case). All would have predator-prey relationships, because life feeds on life. All would have the need to carry and lift and scan, and that means a human form. The minimum common form.

So, all aliens are humanoid, unless they are machine-beings with nonbiological energy sources. If an alien is flesh, it will be humanoid.

Boringly, dreadfully, just like us.

If there really are secret government scientists studying dead aliens in underground facilities around the globe, they should not be puzzled as to why those aliens are humanoid. It isn't proof of some universal god. It isn't evidence that the aliens made us and seeded the earth. It does not suggest that the aliens are time travelers from our own future. Sorry, boys.

It is just that in our universe, in Mundis, the humanoid form is the minimalist shape nature will always drift towards, because of the needs of a biological energy budget. Problem solved.

Boring though.

Poor nonexistent space-squids.

[Alfador]

So, really, one of the most realistic sentient non-humans ever in science fiction... is the Cat from Red Dwarf.

[Anna]

Hi,
just found this thread...
Wow!
Havn't read it all, to lazy and to less time,
but one thing I want to give to the discussion...

Do you remember the TV- documentation "The Future Is Wild"?
The Future Is Wild:The Tentacled Forest
part1
http://www.youtube.com/watch?v=bYYCcEt3_c4
part2
http://www.youtube.com/watch?v=NRI7G0Wp ... re=related
part3
http://www.youtube.com/watch?v=KszDwLtn ... re=related

If you're impatient, you should watch part 3, squids, intelligent squids.
You really don't need a humanoid form, these squids are very "handsome".

Allright, I will get in here later again.

[Coda]

A very insightful write-up, and I quite enjoyed reading it.

But I do take issue with few points.

Fur is NOT a waste. It's only a waste in our climate. Producing fur is, I think, likely to be less of an energy deficit than maintaining a warm-blooded biology in a very cold environment. If we're going to discuss evolutionary pressures, why would there be pressure to select against fur in a species that had not yet developed the ability to make clothes? And why, then, would such a species pursue clothing, if their bodies naturally provide the necessary and sufficient insulation?

A third eye of the same characteristics as the first two may not grant you any additional benefit, but FOUR eyes DOES grant benefit by increasing the field of vision. There's also the possibility of other sensory organs that might be considered "eyes" that sense other forms of radiation besides visible light. For example, a single ultraviolet-sensitive eye could overlay a lot of additional information on top of the 3D image created by the stereoscopic eyes without losing any depth information.

While it's true that the eyes need to be mounted high on the body, and the nose and mouth should be in proximity, and the ears demand stereo separation, there's nothing dictating that all of these sensory organs have to be mounted on the same structure. Ears would work effectively on, for example, the shoulders, and the nose and mouth could be on the abdomen without any significant loss. In fact, respiration taking place entirely in the torso sounds like it would have advantages -- the shorter windpipe would grant less of a weak spot than putting it in the neck -- and putting the mouth closer to the stomach also means fewer muscles necessary to perform peristalsis -- again, an energy savings.

A tail is a waste for bipedal, walking creatures, but you overlook the possibility of an environment that's primarily marine or one that requires brachiation for efficient travel. A tail in those environments would be a benefit that could exceed the simple energy efficiency. Also, bipedal walking is a TERRIBLE waste of energy in and of itself -- it requires great coordination, a specialized body, and constant attention from the nervous system to even so much as remain standing. Our walking is basically controlled falling. It's also SLOW. It's only an advantage because it leaves us with free hands, but the evolutionary pressure to develop a bipedal stance wouldn't be nearly so strong with an ancestry bearing six or more limbs.

Edit: I forgot to mention the possibility of avian development, which would also put significantly different pressures on development than terrestrial or marine environments.

[Relee]

It's more about survival than efficiency. Efficiency helps with survival, or it did in the wild certainly. Humans do have some waste material, excess organs we don't really use anymore and surgically remove. Some humans are actually born with tails, but most would never know it. A doctor will 'correct' that faster than 'ambiguous gentials'.

Cybernetics and alterations are coming into effect. The game of life means breeding, which means you have to attract a mate. That requires you to be special, and to stand out. Your imagination should provide plenty of ways to stand out, given those tools. Efficiency isn't quite the issue it was, since one of our biggest health issues in the modernized world is obesity caused by consuming too much chemical energy. That might be a passing trend, if we keep following our nature and overpopulating, but we'll see how it goes.

It's also important to remember that we're still evolving. Pretty soon we'll have humans living permenantly in space, along with other animals they'll take with them. And I don't mean on planets; microgravity changes all the rules. Humans also have the bizzare property of surviving when they wouldn't in nature, due to medicine. I wouldn't be alive today if I wasn't delivered by a competent doctor, and the medical reasons I might have died then are carried in my genes. That's just intelligence showing its true power as an evolutionary win.

Eventually I imagine we'll break out of the game of life entirely, eating without killing and living potentially forever, but then we'll be cyborgs, constantly modifying ourselves intelligently instead of creating offspring that might have an advantage. Of course, I've gone over that before. ^.^


All of that said, all of it, I do think that most intelligent life will be very similar to humans, yes. Humanoid, at least. I don't think it'll be quite so 'forehead aliens', but two arms with manipulator hands, two legs, standing erect, with a seperate head, will be the norm. The details will depend on the native environment.

[draque]

Jennifer, I think that what you're saying applies in part, but not in whole. Human beings are the way they are due to not only the overall environment we evolved in, but our ancestry. As Coda pointed out, fur would not necessarily be selected against. Human beings first began to emerge in areas of the world where they didn't need fur or clothing for survival. If humans had evolved first where you or I live (Washington state or Ohio, that is to say), I think it's likely that you and I would have fur now. Even if we didn't need it currently, it would be left from our ancestry. Tails, to address the other point you made, don't seem any less likely than the appendix in humans (which is actively detrimental, yet gives very little function in return).

Also, while configuration that human beings have taken solves the problems faced by a species looking to develop significant technology, I also think that it would be short sighted to say that there could be no other solutions to those problems. The ability to delicately manipulate complex tools is a must, and hands solve that problem. There might be other ways to solve the problem, though. The same could be said for most of the other problems as well. Here's a basic breakdown of problems that need to be solved to have a technological species:

SURVIVAL
locomotion: bipedal
other possible solutions: quadrupedal w/ additional manipulation limbs, quadrupedal with walking limbs doubling as manipulation limbs (like the great apes)

vision: horizontal binocular
other possible solutions: horizontal binocular supplemented with additional visual sense (pit vipers, Coda's example, etc), monaural vision if depth perception is for some reason not an issue (an ecosystem with a different relationship between predators and prey, maybe)

vibration sense: binocular auditory (necessary for audio communication)
other possible solutions: direct vibration sensors on feet similar to those in snakes' bellies (high information bandwidth unnecessary if linguistic communication is not auditory/vibration based)

heat retention: technology based/clothing
other possible solutions: fur, feathers, an environment where heat retention is not an issue

heat dispersal: sweat
other possible solutions: heat retention system that can be disabled (as with penguins and their venting feather system), partially aquatic lifestyle, an environment where heat dispersal is not an issue

solar radiation protection: melanin, hair on top of head
other possible solutions: fur, feathers, scales, an environment where solar radiation is not an issue

nutrition: mastication, partially technology based (cooking)
other possible solutions: *special, see below*

TECHNOLOGY
communication: verbal speech
other possible solutions: high bandwidth visual system, tactile communication system, direct vibration based communication utilizing something similar to the vibration sense of snakes' bellies

documentation: primarily visual based writing
other possible solutions: tactile writing (braille), artifact based writing (Aztec knot record system), machine encoding (way too many to enumerate here)

society: humans have it
other possible solutions: I honestly can't think of any. Collaboration seems key.

As a note, I discount underwater technological societies because it would be infeasible for them to develop technologies that required metalworking or relied on significant heat sources with any kind of reasonable ease. This is not to say that it couldn't happen, just that I can't think of how. In regard to nutrition, it should be noted that we have partially evolved around technology. We use fire to prepare food before we eat it. If technology of varying levels is allowed when taking nutrition into account, it seems as though it's much lower on the order of how intelligent creatures would evolve to create a more highly technological society.

Anyhow, this is the kind of thing that it would be easy to write a book on, so I'm not going to even bother trying to make any kind of exhaustive list here, but I think you can see what I'm trying to say. There can be multiple possible solutions to problems facing species that are looking to become intelligent and develop technological societies. Although we've found ones that seem to work reasonably well, our bodies follow the patterns of our ancestors. If our ancestors had been wildly different, we might still have found solutions to the problems, but they would likely have been as wildly different as those ancestors.

[mwchase]

Thinking about alternatives to binocular vision made me remember something. We use a great many visual cues in addition to parallax to judge relative distances. In point of fact, parallax is only relevant up close because, for our eyes' spacing, the effect vanishes once you get far away enough. (This isn't to say that there aren't differences, just that we can't see them.)

So, suppose a creature only has one eye. How would it compensate for the lack of parallax? One thing that lept to mind for me was social structures. Groups of small animals coordinate, relaying messages about performance, where to go next, etc. Since they're small, all manipulation counts as fine manipulation, and each one can just grip something in their teeth/mandibles/whatever. I'm not sure about communication... either each would have a name, and it would be verbal, or they could express things with highly visible movements, similar to a bee's dance, in a way. Note that the visual thing would mean that they wouldn't be able to see what they themselves were doing, and I don't know if that's an insurmountable problem or just food for thought. (I really like the visual option more, because it's so different from how things work for us.)

I've got this whole mental image of colonies imparting knowledge to their young, and then exchanging them between colonies. In effect, meme-sex.

As an aside, the pinhole design of our eyes is not absolute. If an animal stumbled upon wavefront encoding, then eyes could be made virtually flat, while still providing good resolution to their owner.

[masstreble]

Point 1a: The level of technological sophistication necessary to traverse the galaxy as such to result in a UFO encounter would also obliterate the need for any conformity to evolution-based wilderness survival. By the time that we find a way to do the same, we won't look like humans anymore.

Point 1b: What, where's the artificial life? No robots made out of futuristic materials? Somehow I doubt that the majority of those would be anything recognizably bipedal and human-like, it just wouldn't make sense for a lot of them. Honestly, I think we'd be just as likely to encounter such non-biological intelligences out there as anything else.

Point 2: UFO encounter stories are not evidence for anything except for UFO encounter stories. Of course all these different people report seeing bipeds, it's coming out of the imagination of earth hu-mahns! Also, I'm not seeing this consensus anyhow: I've had two different people yammering to me at the same time about their encounters with the militant lizard people, and although both of them were describing slightly different things, they both were insistent about the reptilian features, including a tail. I'm 98% sure that neither of them actually met such any such creatures, except in their heads. Not calling them crazy, just slightly disassociated with reality. Certainly made for an interesting discussion.

Point 3a: What's reasonably energy-reasonable in one environs might be disastrous in another. Take the kangaroo, for example. Ludicrous creatures, right? WRONG. They are highly adapted to the Australian continent, because they can move at remarkable speeds for crazy-long periods of time, at the expense of very little energy. By comparison, we're clumsy stumbling clods, completely unable to get from resource point to resource point without risking death at every expedition. The weird thing is that we're both essentially bipeds. Now, there may be a sentient species somewhere in the history or future of the cosmos that is taking the kangaroo's strategy. A large brain isn't too much of a biological add-on, and could even open up a brand new niche for them, so it could happen, it's just as reasonable and energy efficient as a social, agile knuckle-walker in jungle specializing going bi-pedal and taking to the road.

Point 3b: Intelligence doesn't require a humanoid form. It's only arrogance that would lead one to fail to notice all of the intelligence around us. Brilliant birds, sharp whales, clever octupi. Sure, we build the cars and bombs, but who knows the twists and turns of outrageous fortune? Maybe somewhere in the world of earnest possibility, there are avian-constructed atom bombs to blow up the whole surface of the world. Or an Enterprise that can be used to access green-skinned alien chicks for snogging, you know, go where no bird has gone before.

Point 4: What are you talking about, the bipedal form being the most efficient and obvious -- come on. The most obvious path to sentience is that of an aerial, radially symmetric life form sporting prehensile tentacles. Earth doesn't sport any such beings, an evolutionary glitch, or perhaps not: Earth has unusual weather patterns that may make such a strategy inadvisable. Note that you can't prove any of these claims wrong. That brings me to--

Point 5: We're all pretty much talking out our humanoid butts here. We've no actual data to go on (see point 2), just some flawed but-still-interesting conjecture. It keeps coming back to the same thing over and over again: we just don't have any data on life abroad. For all we know, we could be the only sentient humanoids to ever achieve upper-orbit flight. Maybe all space-faring species are humanoid, and are just like us, except they all have cooler-looking ears and hair color. Maybe we're the only sentient race period. Maybe Earth life is alone in the universe. We don't know right now, and we really can't. Only if and when we start actually finding evidence of other space-faring species can we get to studying it and as I pointed out in Point 1a, it will end up being historical studies of what the sources of the civilizations that we find were, anyhow.

CASE... STILL OPEN.

[Anna]

I'm back again

Please let me give my little thoughts to this thread, even it is very simple made.

Two arms, two legs, two eyes, etc. the rule of symetry.
There are not many lifeforms without it, well we humans have only one heart, and one liver, for example, and there are not placed in the middle, like our one mouth.

All evolutionary steps have to make a sense, or it wouldn't survive.

The "energy" theory is very understandable, and I agree with it.

To have no tail is an early evolution decide, chimps and gorillas also don't have one.
The south american monkeys have a tail and these are very important extremities.
The tail of a whale replaces the legs.

The apperance of a lifeform mirrors the enviroment it lives in.
So, have a look at the convergent evolution

The easiest way is to show it at two aussies, well nearly, the Tasmanian Tiger is from Tasmania


and the Dingo


But to what kind of animal is a kangaroo similar?


This here looks more like a kangaroo, but the life is very different.

Indeed kangaroos are using the same place in Australia as these nice critters do it in the rest of the world.

They are looking different.
So sometimes there is more than one solution possible.

What about intelligent lifeforms outside earth?
Are they really allways humanoid?
Or mabe the humanoid aliens told to the others,"Don't come to earth, the humans are easily to be frightened and a panic always in the air, let us do the job."

A squid can indeed be an energy saving being.
No extra body, all compact in one big bodyhead. It can save energy and also the body temperature.

But one thing for an earth squid is important, you see, infact we humans are fishes, evolved fishes with bones, which helped us not only to master the gravitation on an island but also to get some stored life supporting elements which a fish has always in the ocean.
A squid living outside the water would need this too, even it has no bones.

An insect of earth can not become very big, the breathing, the exoskeleton does not allow this.
Soemtimes if I'm driving through the city, I imagine that all these cars could be very big bugs, and I wonder why this wasn't possible for the real bugs. Well, a car has an inner skeleton, and the hull is only placed on it. That's different to a real bug. So big big bugs should have been build more like the other animals, they need an inner skeleton, an exo thing would be to heavy, and they would need blood circulation like we have, also a better breathing system.
Bugs of earth can't become big, only if the evolution makes giant step.
Well I can imagine, that some kind of insect states could become very intelligent, but this would implement that there is a "brain bug" like in "Starshiptroopers", but much smaller, you see, our brain is not so big, and the construction of an insect brain is different to ours but very effective maybe more like ours, if this would be big enough, Maybe a brainsized insect, supported by its insectstate to survive, ahm, imagine the state as a body.
Or, taking this idea, many insects are conecting together to become a brain as a module formed intelligence.
If they split away, the master intelligence is gone, for a while.

Allright, maybe these described lifeforms will never make it to become an intelligent lifeform alike we are.

Newest discoveries are saying that a dolphin has possibly indeed an intelligence wich is very close to us.
But they don't create a culture, so what makes humans to humans? And what prevents dolphins to make this step to us?
No hands, they live in the water, but couldn't they create a culture of talking, whales are singing, why shouldn't this be great sagas of the oceans? It seems they are not, they are possibly only on the level to tell: here I am, you are there.

Or easier to ask, why are chimps no humans? They are real close to us.
They live in an eviroment like us, the same we did evolve to what we are.

Ok, I did read years ago about the waterape theory, and I think there is something in it.
But I don't think that this is an explanation for our intelligence, a part of it, maybe.

However, I can only speculate about aliens from what I see here on earth.

[Anna]

By the way this here looks like a spacesuit for squids.
just found on Bing picture search.

Don't ask what it is

[strange_person]

Picture something built a bit like a spider. Horizontal segment, containing the digestive system, jointed to a vertical segment containing the respiratory system. Six limbs, hind pair locomotion only, front pair fine manipulation, middle pair, clawed, alternates coarse manipulation and locomotion. Eating mouth, beaked, between the middle limbs, excretion between the hind limbs. Atop the vertical segment, a bulbous compound eye, exquisitely tuned to movement and edge-recognition but blind to color. Between the lungs, a retractile tentacle (like the prehensile penis of an orca) holding a slow-focusing color-sensitive eye, which can be extended through breathing orifices under the upper arms. Genitals in the palms of the upper hands, womb on the inner curve of the joint between the two body-segments. Upper hands also act as scent-sensors, licking potential food, mates, or just the air, then depositing residue inside the eye sockets, like a snake's tongue. Main brain inside a chitinous camel-like hump on the lower back, with a secondary node of visual pre-processing and reflex actions just under the compound eye. Vibratory sensors along the lower four limbs, equidistant from the brain.

Two more limbs, yes, a bit of a metabolic penalty there. However, that's more than compensated for in ability to gather additional food by piling it on the back, to swim or climb trees while holding a full load, to specialize joints for degrees of freedom vs. resistance to damage. Bulbous bug-eye protects from predators, leans forward to track obstacles for rapid movement, but with no focal depth or moving parts it can be more resilient than our squishy jelly-filled orbs ever could. Tentacle-eye permits tool use and detailed interaction with the environment, but shelters inside the body when unneeded, and is sufficiently far from the mouth at all times. When standing still, sensitivity to vibrations in the ground allows precise tracking of direction and distance, so hunting is possible in the dark or through undergrowth, where eyesight would fail. Brain-hump can expand out of proportion with the body, as social systems become more complex and necessitate clever rule-bending, without becoming mechanically vulnerable like the human cranium and cervical veretebrae.

[flammifer]

I don't think humans are very near the optimum for sentient beings.

1) Evolution is nifty, but has it's limits. It's kinda dumb and purposeless, and only finds stuff out after a lot of trial and error, and often comes up with quite awful designs. So while convergent evolution happens (ichthyosaurs and sharks, Anna's examples, etc.), plenty of species are probably very far from the "ideal form" for their situation. It's like asking five year olds to draw the Mona Lisa - sure theoretically they should end up with the same thing, and sometimes they do, but the average drawings will be as far as we are to green babes with prehensile tails - both aiming for the same thing ("the minimalist humanoid form"), but falling far.

2) Evolution doesn't lead to the "minimalist humanoid form", it just advances in the direction of which type tends to make the most kids. And if that means huge impractical but impressive antlers, or huge impractical tail feathers, then so be it. A moose without antlers may be more efficient, but if it doesn't get laid, tough luck for it's genes, cousin gets-stuck-in-trees-all-the-time gets the medal. Efficiency is only a factor when less efficient individuals get killed before they can reproduce. Which may be the case for rabbits in an environment with a lot of predators, but less so for humans.

3) Evolution may converge when given the same environments, but on another planet the environment can be quite different - gravity, temperature and air pressure, which might lead to a different equilibrium for the composition of the atmosphere, which might lead to different plant forms (if there even is a similar plant / animal distinction), which might lead to even more different animals. The ideal target form towards which evolution would converge even if it wasn't bloody stupid and didn't get distracted by shiny "sex appeal" features may be radically different.

[Wizard CaT]

Hum ho.

Firstly guys, she said humanoid biologicals. She already said AI could be any form. Fur wouldn't be against what she said, just against tails, and by the time inter-planet travel is available, it'd be gone.

Which isn't to say she is right. I mean she is pretty wrong. You'd almost think she believed in intelligent design. Evolution, that is to say, random mutation, is a random mutation. There is no reason that the "best" design will take over. I mean fuck, peanut allergies were uncommon because people DIED from them. Now that we can save people, peanut allergy is on the rise. How is that evolution towards the greater energy efficient good? How many genetic diseases are still around? E T C. And the crap mentioned in that wiki article.

Also we are limited by energy, but what about creatures with a much higher energy intake? Or able to get more energy out of what they eat? Piss & shit = waste after all. Hell, what about sentient plants or life with chlorophyll?

[masstreble]

Evolution, that is to say, random mutation, is a random mutation.

Wha? Nooooo. Evolution is not random. Some of the mechanisms, like mutations, do include chance, but that's not the driving factor. That's what natural selection is all about.

Of course, you're right, it also produces some really silly defects in individuals within a population. Not to mention vestigial stuff that is sometimes problematic. Hell, sometimes you see things that are pretty much being selected against right before you, like childbirth fatalities. I'd predict that if not for civilization (which is going to be something like a special and really cool extinction event if we're lucky), then I would say that humans and their bipedal cousins would eventually have some refinements of the bipedal form that makes childbirth easier and less risky.

Oh, well. I'm what I am and I'm here now. Best not to cry over spilled allele frequencies, ey?

[Alfador]

It's more about survival than efficiency. Efficiency helps with survival, or it did in the wild certainly. Humans do have some waste material, excess organs we don't really use anymore and surgically remove. Some humans are actually born with tails, but most would never know it. A doctor will 'correct' that faster than 'ambiguous gentials'.

That's just what I was going to point out: As Jenny said, "nature is a frugal bitch", but what that often means is that it's more efficient to just disable an organ's most energy-draining functions rather than to get rid of it entirely.

Why do we have long head hair that grows and grows? After the point where it protects our head, more hair is less efficient than just growing more fur elsewhere on the body where it could protect, because longer hairs get pulled out easier and have to be regrown, sucking up more energy than just keeping some short fur on top and wherever else needs extra protection, say, from sunlight. Why do we need an appendix? Earlobes? A leg structure that requires kneecaps? Answer: Because it wasn't enough of a burden to be worth getting rid of them.

P.S. Also, why are we assuming an intelligent, spacefaring species would appear exactly as evolution molded them? We already have zillions of people on Earth who implant metal, silicone, ink, and other materials in their bodies to drastically change their appearance. Why wouldn't an advanced civilization have people who dick around with their appearance, perhaps even creating entire custom bodies to appear, to themselves, "really awesome"? Just because our culture probably wouldn't put somebody with a giant green mohawk and seventeen piercings in a spacesuit to be the first human on any given planetary body... doesn't mean alien cultures would have a taboo against sending their "freaks" out to explore strange new worlds. Hell, the weird folks would probably be the most WILLING to seek out new life and new civilizations--they'd have the best chance of not freaking out over OUR cultures.

[Wizard CaT]

Evolution, that is to say, random mutation, is a random mutation.

Wha? Nooooo. Evolution is not random. Some of the mechanisms, like mutations, do include chance, but that's not the driving factor. That's what natural selection is all about.

Hum ho, yes to a point. The mutation occurs, and if it's bitchin' then it will be carried on and if it sucks, then it dies out. In nature. Then nature's mistake (us! ) get involved. Beneficial means nothing. Natural selection means nothing. Basically once we can modify ourselves, it's over. People with glasses wouldn't survive as well, but we give them glasses and it evens out. Add to it some people find glasses cute, and it makes your disability MORE likely to get passed on. Sure, maybe some blind fish in a cave are ruled by natural selection and shit, but we are a bit beyond that. We've started to modify our own genes! Hell, Alfador is going to pass on his genes [well the chance], but as he has mentioned he should never have been born.

[Tychomonger]

By Jennifer's argument, we are only continuing to evolve by shaping our environment. By taking selection pressure away from good eyesight, we allow other genes to dominate the scene, and we can select for spending more glucose-bucks on brainpower.

[mwchase]

Not a good time for me to watch the video right now, but quick observation: any changes in brainpower would have to come into play after birth, unless lots of women start to lose use of their legs. IIRC, brain size at birth is precisely balanced against the degree to which the pelvis can accommodate a large head, while still allowing the mother to walk.

[strange_person]

IIRC, brain size at birth is precisely balanced against the degree to which the pelvis can accommodate a large head, while still allowing the mother to walk.

It's also balanced against the mother's ability and willingness to get some kind of surgical intervention, which was historically stuck at 0.

[Coda]

It's a shame that genius-level people also have a tendency not to reproduce.