Aliens would kinda have to be similiar.. right?

Miscellaneous and Personal Stuff I Must Share
1

I read this article on cracked (my SECOND favorite website from work):

And yeah, I agree with most of it… kinda makes sense. But the more I think on it, the more it seems that aliens would (at least at some time in their existence) look like us… right?

Sure, Dolphins are smart. But how does that translate into creating technologies needed for space exploration? Dolphin flippers are awesome, but can they be used to mine the earth, create metals, while being small enough and dexterous enough to also create a microchip or write code?

In a million years from now I dont expect Humans (if we still around) to look anything like we do today. Even if we evolve into soft boned, lazy blobs of flesh, because Robots of course… that wouldn’t have changed the fact that at SOME POINT any species that can reach the stars would all have to have some traits in common along their evolutionary history.

If ants one day become the dominant species on this planet they may evolve into some type of species that has human level intelligence, but if they dont have hands or bodies capable of smelting ores… they aren’t leaving this place.

I’m fairly certain i’m missing an obvious point that makes this seem like a waste of typing. Which is why its here and not in GD :slight_smile:

2

Passing Mod… can you add the missing verb in the title??

“… have to BE similiar…right?”

if you are so inclined :slight_smile:

thanks!

3

Would a crab look like us? A crab could evolve sufficient dexterity with multiple pincers to do everything we do. That’s just sticking with the individual autonomous animal model, the aliens could be colony creatures composed of many specialized subtypes with far greater physical capability than we have. And why assume aliens only develop on something like a planet, I don’t know how but perhaps beings can form in the clouds of space that need little to no physical capability like ours, but can still travel the universe by generating EM fields to exhaust matter, or just figure out some way to do things we haven’t even thought of yet.

4

I think Earth itself provides plenty of examples that aliens don’t have to look like us.

Crabs are one good example.

How about elephants? They’re pretty close relatives to humans (compared to crabs, at least), share the same bone structure and other traits… but with a manipulative nose, a space-faring elephant would look less human than ET did.

5

I don’t see a compelling reason for aliens to look like us. Science fiction writers have invented all sorts of different alien forms. Even if you buy the usual arguments for the general layout – keep sensing nerves short relatyive to the brain, so sight, hearing, and maybe taste are in the same place. You want a stable and mobile form, you probably evolved from a similar body plan, etc. it’s not clear that you get something that loks like us.

Who says you only need two eyes for binocular vision? why not three or more? Plenty of creatures have three eyes. Spiders have many more.

Who says you need a camera-like eye, such as humans and octopus have? An insect-like eye would give you a much broader range of vision. Why not an eye like a mantis shrimp, with not only insect-like lens+sensor components, but also built-in frequency filters and much improved polarization sensitivity.

Does an alien need eyes at all? It m,ight be effectively blind. Or it might “see” by detecting sound, or it might be sensitive in different parts of the spectrum (although it would require specialized environments. Or it might have some odd sense that combines scent and vision, as in Hal Clement’s short story “Common Sense”.

Why have the brain in a specrate head with a higfhly vulnerable neck? Why not in the center of the torso?

Larry Niven made the suggestioin in one story that aliens might have started out as we did, but their ancestors got chased out of the sea while still using six fins, and might have evolved to six-limbed creatures, like Edgar Rice Burroughs’ Tharks. There are certainly other ways to get there, of course. But we can’t rule out other forms of manipulation and locomotion. Tentacles, caterpillar-like “false limbs”, elephant trunk-like structures. What if creatures evolved from dolphin-like creatures, and had a prehensile penis that doubled as a manipulation organ? What if humans had retained tails? What if creatures developed tongues that served in stead of hands, or were like Niven’s “Puppeteers”, which have a brain in a torso, but eyes in two head-like appendages that each had an eye and a mouth, which was equipped with knobs on the lips that could act like fingers?

For that matter, why assume that creatures must be symmetrical? Niven loved asymmetry, which shows up multiple times in his work, most notably in the “Moties” in his novel The Mote in God’s Eye (and its sequel, The Gripping Hand).

We look the way we do because of a series of adventitious events. There’s no reason to believe that intelligent aliens would develop from a similar set of events, or that convergent evolution selects for structures identical to ours if the environment is different. Or even if it’s the same, for that matter.

6

The whole “bilaterally symetrical” life-form would seem pretty unique to earth and I see no reason an alien life form, unless related to us, would take on it’s unique characteristics.
Left/right symmetry, a head containing the brain with bi-lateral light wave and sound wave receptors. Left/right arms. Left/right legs. Critical organs in a torso.

I’d think aliens would be something of an entrely different makeup.

7

I’m not saying all alien life has to look like humans, but it does seem that any alien life that develops on a planet would need very similiar features that humans (phyiscal traits at least) have in order to do all the things needed to create the technology for space travel.

They may not look like us now… after they evoloved a million years past space travel, but at some point they would have needed to do the same things we do… right? kinda?

8

They might need to do some of the same things we do, but there’s no reason to think they would necessarily do any of those things in a similar way. On the most basic level, all you can really assume is that they can a) perceive their environment and b) manipulate their environment. Cal pointed out some fairly easy variations on those theme in his post. They might also have crucial needs that would never occur to us–maybe they evolved a structure that deploys as a shield against ionizing radiation, because their star was prone to flaring, for example (or maybe it absorbs ionizing radiation because they feed on it, or something).

The point is, to the very basic extent that they would be doing some of the same stuff we do, they might be doing it in ways that are completely unrecognizable.

9

What causes bilateral symmetry?

The most basic kind of symmetry is spherical. But if you live on a planet there’s a constant feature of gravity that always pulls in the same direction. Even in water there are gravitational gradients for substances that are either denser or less dense than water.

And so only very small creatures tend to be spherically symmetrical. Introduce gravity and you have creatures with a top and a bottom, and now you have radial symmetry. Lots and lots of sessile organisms are radially symmetric.

But lots of mobile creatures have sensors and nervous systems. If you move toward food then it makes sense to have your mouth on the side of the body that the food will encounter first. And it makes sense to have sensors on that side as well, so you can interact with the food. And it makes sense to dump your waste products behind you, so you’re not constantly walking through a cloud of your own waste.

And so bilateral symmetry has evolved over and over and over again in the animal kingdom. And so you have a cluster of sense organs around a mouth, a nearby nerve cluster, and excretory organs at the back. Since we already have an organ to excrete material from the body often gametes are excreted from the same organs.

And so any organisms complex enough to build space ships are probably going to be bilaterally symmetrical. They’ll have to manipulate materials, so they’ll have manipulatory organs. They’ll have to have sense organs and ways of communicating. They’ll have ways of ingesting food and excreting waste, very likely the mouth will be near the brain and sensors, and the excretory organs in back.

Does that mean a bumpy-forehead star trek style alien? No, because so many parts of our particular body plan are consequences of the particular evolutionary history of vertebrates, tetrapods, mammals, primates, apes, hominids, and humans.

10

It is interesting that bilateral symmetry won out on this planet. An octopus in the right environment could do anything humans could even without a skeleton, though any thing that lives on land would probably develop a tougher or more complex skin and rigid supports. I’d guess that bilateral symmetry is much more efficient than radial, and more useful than unilateral symmetry. I suppose if snakes and worms could communicate and cooperate well enough something along a unilateral mode might work. I realize those aren’t true biological categories, snakes do have bilateral symmetry, but I’m using those terms to describe general construction.

Dob, we do tend to imagine alien beings that live on land and use mechanical technology, and for those circumstances it may be likely that we’d find something similar to earth animals, but there’s still no reason they would resemble a human any more than a crab does.

11

Technically, octopus also have bilateral symmetry. It is the default for almost all macroanimal life on Earth, in large measure because it provides balance, first in swimming through the ocean and later on land, and of course in flying through the air. All mammals, aves, reptiles, fish, and insects (as far as I can think of offhand) are either bilaterally symmetric or are derived from an atavistic form that was bisymmetric. Only some shellfish and echinoderms, and some colony animals like jellyfish and man-of-war, are actually radially symmetric. But even this may well be an accident of evolution rather than a necessary condition.

I don’t think we can assume anything about the form of a totally alien life form based on what we currently believe to the the necessary technology would be to conduct interstellar travel (if and when that ever becomes a reality). An alien form of life will very likely have a completely different evolutionary chain. It could develop in an ocean and use enzymes to construct structures and their analog of computers or other complex devices rather than smelting and casting solid metals. They could use electrochemical reactions rather than fire. They could secrete waste from their mouths and sit on their brains. The octopus–a creature that is just about the most ‘alien’ macroscopic life we can point to, and has very different evolutionary solutions to eyesight, respiration, manipulation, communication, and a highly distributed nerual system–is nonetheless considered highly intelligent and would be a good candidate as a potentially species which could be uplifted to sentience (if they don’t already enjoy it) and industry. And truly alien life will likely be far stranger and have a vastly different evolution than any comparaison between octopuses and primates.

I don’t think we can assume much of anything about sentient alien life beyond having some kind of cellular-like organization, differentiated organs or internal division functions, a complex nervous system with one or more centralized centers of cognitive function, and some likely but not assured means of homeothermic regulation. Even those very general categories make some significant assumptions for which we have exactly one data set (life on Earth) from which to extrapolate. It is very likely intelligent alien life would not be apparent to us, or we to it, especially if there is a large gulf of technology or scale. A planet-sized intelligent creature might see the Earth as a whole as a living organism and humanity as a virulent parasite infesting it, while a massively intelligent race might regard our limited calculus of whole and rational numbers (with irrational numbers only approximately represented) as utterly trivial and incapable of representing real physical phenomena on a fundamental level just as we regard the barking of dogs to be barely communication.

Stranger

12

Human bodies evolved intellect the way they did, because the various processes they already had allowed for advancement. Any other organism that was heading down a similar path of being able to take control of its environment, would probably have discovered that the absence of limiting disabilities proved more important than the presence of useful body parts.

There would have been a time in history when primates were not the best developed brains and intellects on the young planet, but those that had advanced the farthest ran into a wall, and could not go farther, because they were underwater, or had to hibernate, or had no free limbs to manipulate things, and the primates passed them up. Similar limitations would have doomed early brainiacs on any planet. Intellect had to wait until a species in a suitable body evolved intellect, so it could take advanage of it and progress…

13

I think that f there is a great deal of life out there, much of it will be truly alien to us, to the point where we might not recognize each other as life. There would also be aliens that are clearly alive but have thought processes so different we would have no way of communicating. But, I suspect, any alien species that would be interested in our planet and interested in contact with us would probably have something in common with us both physically and mentally. Enough that we would be able to recognize each other as sapient life at least.

14

“I know I’m human. And if you were all these things, then you’d just attack me right now, so some of you are still human. This thing doesn’t want to show itself, it wants to hide inside an imitation. It’ll fight if it has to, but it’s vulnerable out in the open. If it takes us over, then it has no more enemies, nobody left to kill it. And then it’s won.”

I suspect John Carpenter’s vision of alien first contact is not unlikely. At best, we might run across aliens akin to those in 2001: A Space Odyssey or Rendezvous with Rama; ineffable motivations and indescribable form. A future more likely Eclipse Phase than Known Space.

Stranger

15

Most of evolution is a series of complete, random accidents. I think it would be completely astonishing to discover a space-faring alien that even remotely resembled us. To the point where we wouldn’t even recognize it as a living being.

16

I’m down for the customizable, swappable bodies and cornucopia machines. The rest of it would be a harder sell. :slight_smile:

17

I’m thinking our robots meet their robots as referenced in the article in the OP.

18

Dolphins Evolve Opposable Thumbs.

19

No it’s not. It’s a very large number of accidents, filtered by a smaller number of selective factors.

Given similar selective factors, the white noise of accident could be filtered out into some similar-ish solutions to the same problems; we know this is possible because there are examples of it here on Earth - the evolution of eyes, wings, mouthparts, jointed legs for example, have been played out multiple independent times in different lines here on Earth, and in some cases, have brought about kinda-similar end results.

Of course, there’s greater diversity here than there is coincidential similarity, and I’m not saying we should expect Star Trek aliens who only differ from us in the shape of their nose, forehead or ears, but given similar environmental conditions, we should not be terribly surprised to discover some of the same problems being solved in similar ways; that is:
[ul]
[li]Vision being performed by something that is recognisably an eye[/li][li]Flight being achieved by something that is recognisably a wing[/li][li]Intake of sustenance being processed by something that is similar to a mouth with jaws and teeth[/li][li]Locomotion being done on jointed legs[/li][/ul]

Anyone who has played the beetle game will know, there are ways to assemble all of the above that will still look very ‘alien’, and there are no doubt other solutions to the same problems that haven’t happened to arise commonly here (flight by buoyant gas, for example). Aliens will be different, but some of them will share similarities with life on Earth.

20

In those novels it’s pretty clear that asymmetry is the result of DNA alteration through multiple nuclear wars, and that many moties retain a stub of a 4th arm.

The large arm is really just an adaptation of ‘handedness’, much like a Fiddler crab.