Evolution

Besides manipulators, which covered, technology also requires social interaction. Any sentient, technological species is probably going to have adaption for both passive and active information-dense communication.

as far as I can tell, the only requirement for intelligent life is conditions that aren't harsh enough to kill everyone, but still harsh enough that only the most intelligent will be able to survive, constantly, generation after generation

>Wrong on every count.

Quite the opposite, I bet you don't even know what "sentient" means.

Being bipedal makes your point of view be higher than most quadped animals, making them easier to spot in tall grass.

I imagine aliens would be bipedal due to that too.

Humes are bipeds because they evolved from quadrupeds, and repurposed the front limbs into hands.

So... Animals aren't sentient?

Okay there's a bunch of autists(lol autocorrect made it say artists) on this thread dogging you for saying sentient. Last I heard dolphins were sentient and they don't have arms or legs. I think he means intelligent life forms that develop science and space travel and feel emotion and use critical thinking and language. He means like humans.
I think it wouldn't matter, but I feel like being an underwater lifeform would greatly stunt your chances at being able to create and research and learn. I feel like arms hand and legs all serve separate purposes and allow us to easily manipulate the world around us which makes us learn and shit like that.

there is no intent in evolution, therefore "repurposed" is entirely irrational

its pure random mutation + survival

nothing else

>there is no intent in evolution,
>its pure... survival

Cue philosophers talking about the meaning of 'intent.' Just don't.

There is a theory that humans evolved their current shape to be good at throwing.
If that theory is correct, alien species should have a shape that is optimized for throwing.

Is there much information about how good other animals (apes) are at throwing?

Chimpanzees can't throw with any deal of accuracy or strength. Even when they fling their own shit they miss often

there is no animal that comes even close to human throwing speed and accuracy.
I dont this this is a coincidence

>If that theory is correct, alien species should have a shape that is optimized for throwing.
How does that follow?

God, I hope not.

It probably won't be that bad.

well, I dont think it is a coincidence that we are the only species on earth that is both civilization building and good at throwing.
If aliens take a similar evolutionary path as we did, they would also evolve a body that is optimized for throwing.
It doesnt need to be humanoid, but it is hard to come up with other body designs that can throw efficiently

>and they didn't make the evolutionary step out of the water.
just because they didn't here doesn't mean they couldn't elsewhere

They are sentient - they sense/experience things.

Sapience is intelligence. Self awareness is often a characteristic that is synonymous with intelligence - see baboons attacking their reflection, but bonobos using their reflection to help with grooming.

Not necessarily, to my understanding, throwing was just a trait that developed because humans already had the prerequisites. Humans already had incredible depth perception from being descended from primates, they had proper shoulderblade rotation and arm length, and bipedalism helped develop proper throwing motion. Regardless, there's no denying the impact throwing has had on humanity, it's pretty much the reason we fight exclusively with ranged combat, or at least the reason we devloped it so extensively.

no, but they must have an evolutionarily plausible number of legs, that's logically necessary.

Bump

Of course. But consider the physiology; as soon as something bigger than an insect leaves water it has to have lungs. As far as I'm aware, everything we know of with lungs also has a rib cage to act as a bellows mechanism to get air in and out. If their were some other mechanism for say an octopus to develop lungs which had some kind of pump mechanism then there's a possibility. But not having an endoskeleton is a bit of a drawback out of water.

Tentacles might work if the host also has a skeleton, but in evolutionary terms which would have greatest advantage, having a skeleton throughout and hence hands and fingers, or having a part skeleton and tentacles?

The possibility of tentacles might be most likely in a creature which didn't have an endoskelton, but did have an exoskeleton. For example, a cuttlefish. It would be possible to have a hard shell creature with tentacles at both ends which had an internal muscular pump mechanism for lungs, and was able to move around out of water. But it would be very limited; our skeletons don't just provide support and protection, they offer in engineering terms, the mechanical advantage of levers to enhance muscle action. A creature moving around on tentacles would be very weak. Also it would have little defence beyond teeth and retreating into its shell.

I'm trying to think of possibilities which might work, but every one I come up with has physiology stacked against it. Which in evolutionary terms, means that there would probably be something else in its neighbourhood which would be stronger, faster, and more capable of eating it.

>legs are necessary

You can resolve the lung problem increasing oxygen pressure, like in Carboniferous.
Another planet, different rules. Different gas concentration, maybe different biochemistry.

Perhaps this could be useful.
m.youtube.com/watch?v=LrLmHv4Fv4M

On earth, yes, the humanoid shape is one logical conclusion of a species. This can be totally different on other worlds, however.

How and why? Please explain further, and answer some of the points above which query this.

Fuck I don't have 43 minutes to watch this. Do you have a tl;dr?

It mainly goes over 4 planets: a low-grav planet (no life shown), a high-gravity planet with insect life that can fly with large soaring wings, Europa (Jupiter's moon), and Greenworld (pic related). There was also some mention of artifcial life, but the video cuts out before it goes into detail.

Also related

Larry Niven's Puppeteers.

There was also a mention of Sulfuria, a planet with a similar structure to Io.

Thanks. I flicked through it. They didn't go larger than those insects though, no attempt to show how a non-humanoid techno-sentient being might develop.

The pteropede, one of the high-grav planet's main inhabitants.

dude, if it evolved, then it has to have a plausible number of legs. that could be 0, but if it is, then you have to consider how future developments could occur with that as a starting point. if you think about whales, they are meant to have a common ancestor with mammals, yet whales have 0 legs, while other mammals have 4, and of course humans have 2, so that forces you to make assumptions based on the logically plausible number of legs that the common ancestor could have.

Your welcome, and yeah. I don't know why that is, but from I read, the female voice you hear is a green alien (not sure if humanoid)
Also, this is a Europan grazer.

There's also this cgi Kwank (Greenworld) which I think was use in the show. I think the degraded quality of the video does these some justice.

I just remembered, there's also Heliconia (planet from a book series) and Epona
eponaproject.com/Epona_Home.html

Very possibly. If a high enough oxygen concentration gave us metre-long dragonflies in the Carboniferous, what else could it do? Allow insect brain development? Brains use a lot of oxygen, I don't know enough to say whether increased O2 concentration would be enough. The insect would also need a more active respiratory system, more pumping. If these things were overcome, could we possibly see a three foot tall intelligent insect?

Even if we did, some things would have to change. Compound eyes wouldn't have the resolution for fine detail so they would have to evolve simple eyes like us. Insect front feet would develop into something for dextrous grip much like hands.Mouthparts could still be strange to us, depending on their diet.

yeah, I mean Evolution predicts that humans and spiders can have a common ancestor that shares both the features of a spider and a human. However, that common acnestor would also have to have the features of all the other mammals, because the spider-human ancestor would also be the acnestor of all mammals. That gets to be pretty complex.

WHY WOULD THEY BE ABDUCTING US AND PILLAGING OUR BUTTS IF THEY WERN'T SEXUALLY COMPATIBLE.
NOT FOR PROCREATION MIND YOU, CUZ JESUS WOULD LIKE IT, BUT I MEAN FOR LIKE 'TOUCHEN' REASONS.
THEY TOUCHEN, THEREFORE THEY MUST GLOVE ACQUIT.
OR SOMETHING.
#LOGIC
- REDNECK SCI GUY

I MEANT JESUS WOULDN'T LIKE IT!
OH LORD JESUS, PLEASE FORGIVE ME FOR THAT TYPESO.
- REDNECK SCI GUY

if you think about it, the common ancestor between humans and spiders actually isn't physically possible. Just think about the number of legs it would have had. Spiders have eight legs, humans have two, so you might think the common ancestor should have had 5 legs. However, the human-spider ancestor would have t o have had the features of the common ancestor of MAMMALs, not just humans. Since humans have 2, and other mammals have 4, then the number for the mammal ancestor would be 3. The spider-human ancestor would be (8+3)/2, which is 5.5. The human-spider ancestor would have to have had 5.5 legs, which is not a possible number of legs. If you have half a leg, it's not really a leg. You can have 5 legs, you can have 6 legs, but you can't have 5.5 legs. I think this means humans and spider would not have had a common ancestor, so they are from separate lineages in a family tree. Spiders might be the brother-in-law, and humans would be the brothers

Is this because of body shape or just the ability to utilize technique? Are you telling me that if I had a gorilla body, I wouldn't be able to pitch 120mph boulders if I practiced the technique? I imagine it's like fighting, insofar as humans have developed punching technique and fighting stance to fight better than an untrained human who relies on instinctual slapping, and gorillas and chimps only slap

And dolphins use their dicks for grabbing and manipulating things.

I always wondered what would happen if another planet produced that.
Imagine: our first contact with an alien life-form is a handshake to us, but a handjob to them. I'm sure we'll be good friends because of that.

Bump with gif

Better version

>still beleiving in ayylmaos
>2016

>using current year
>triggered

Actually, they did. They just didn't mention it. Behold the Uther, Epona's current sapient lifeform.

I had high hopes for this thread, that somebody might want to talk physiology, evolutionary biology and physics, but fucking hell Veeky Forums.

Oops how did I miss your post, sorry. I'll have a longer look at the video.

It's alright user. Here, have a forest of pagoda trees.

Also, there's this
stevenhanly.deviantart.com/gallery/44352164/Epona-Project
And this
eponaproject.com/Epona_Home.html

Bump

Bump with a Springcroc

On places with earth like gravity and oxygen yes...

But even in gas giants there could be...something....lurking in the density...
You just do not know what is in a molecule soup untill you go....

No not really. Creatures on earth all look similar because they all have common ancestors. All animals on earth are variations of the same archetype, all part of the same family.

Lifeforms on another planet would probably look completely different than human lifeforms, but similar to each other because they too would have common ancestors.

Is there some huge barrier keeping cephalopods from sentience? It seems like they could evolve in that direction given the right conditions.
There are cephalopods with up to 100 limbs.

Cephalopods, especially octopus, the best candidates for spaience, are infamously solitary, it really keeps them from developing any kind of society and the mindset that comes with that.

How THE FUCK do you know what a Springcroc is? Epona is probably the internet's oldest niche (hehehe) project

There are several: they use distributed intelligence and they're aquatic invertebrates.

I have my methods. Also, astrobiology always fascinated me, I think I actually created a world once.

How about this?
nasa.gov/feature/jpl/cassini-explores-a-methane-sea-on-titan
Could our water be hazardous to other life, yet what's hazardous to us be normal for them? And isn't Europa covered in ice? Couldn't there be some fish hidden within?

Depends on your definition of "fish."

As long as it's alive and moving, I'll accept it. At least some form of hyrda or protozoa. That'll be enough for me.

It's funny that you mention that.
m.youtube.com/watch?v=uakLB7Eni2E

Of course, but let's be honest... We can barely see/study our own deep sea fish (specially the ones living in the hadal zone).
I did a huge project based on them, and it pains me I'll never get to see a living one in my lifetime. Answering your question, what's hazardous to one species could very well be common for another. Our hadal zone fish cannot survive outside of it, their bodies are made for extreme pressures and become literal goo when brought to surface.

Life on Titan. Just imagine

Yeah, that's the reason we can't really study them in their habitats let alone take one for a lab analysis. Never mind taking a fish from outer space back home. I've always been into this stuff since childhood and it pains me to see we haven't gotten any farther from going to the moon.

Could mining meteors give us superior ores and materials needed to explore our sea and solar system? Can we even do that?

We don't really need to bring them back for proof. Just seeing them would be a once in a lifetime experience. I just hope we get a probe to go under the ice and find something before I die.

On the other hand, spiders have eight eyes. Humans have 2 eyes, and so do mammals. That means the spider-human acnestor will have had 5 eyes, just like you would expect. If spiders had 7 eyes, it would not work. However, this seems to actually be evidence in FAVOR of a common acnestor between spiders and humans/all mamals. There is another test for common ancestry, which is to look at the dna. If two species are descended from a common ancestor, then you would expect to see the same sequences of dna in both species. However, the spider genome has not been found to be identical to human dna in that respect, which is a result AGAINST relationship. The same is true for chimpanzees. If you look at chimpanzee dna, it may be similar in some places, but that's because it needs to do similar things (regulate bloodflow, make white blood cells, etc). In fact, humans have not been found, contrary to evolutionary prediciton, to have the same dna as ANY species whose dna has been thoroughly investigated.

Bump

Bump

Pretty good body shape for fluid tool usage.

Obvious trolls aside, has anyone got anything substantial to say on this? Just "alien life would be different" without any reasoning isn't much use. If you think it would be different, say why. And ffs read the posts above first. We've already covered OP's use of the word 'sentient'.

>dat cameltoe

...

It would be better to be like a centaur then. You got a free pair of arms andthe advantages of4 legs.

Hell on public transport. But seriously, I wonder if the physics of heavier gravity planets would make six legs more efficient than 4, and a centaur-like evolution a possibility. This is only a vague thought, I don't know enough about biomechanics. It's kind of intuitive to think heavier gravity means more load in the middle of a four legged creature?

Bump

It's just lazy and unimaginative. I'm playing stellaris right now and pretty much every alien race is just an insect or an animal in humanoid shape

Throwing spears isn't the only way to hunt bra. There are negroes in Africa playing tag to chase down antelopes as we speak. Then they just tackle them and stab them

Centaur shape isnt as flexible as the humanoid one though.

Less legs is always going to be more efficient, setting aside stability issues.

>fucking pursuit predation

It depends how closely you define humanoid, but even then it could come in other packages. Sentience and the ability to manipulate one's environment seem to go hand in hand, no pun intended. It stands to reason if something has high intelligence it's because it needs it or has use for it in very visceral terms. This could be more to do with strategizing than making and using tools, but again those go hand in hand.
Why couldn't an intelligent species be water-bound? On Earth there's plenty of free-flowing deep water; on Hypo-Hydro b there could be twice as much, and a limited or unfriendly atmosphere. Just once I want to see a sci-fi story where we meet aliens and their spaceship is full of water.

If it's like the human brain (although that caveat kind of goes against the thread), that wouldn't be the big limiting factor. Where the human brain really taxes the body is in consumption of calories. When a human goes from asleep to awake to solving a simple problem to solving a complex problem, oxygen consumption doesn't change that much, but blood sugar depletion has a big big spike, IIRC it can be 1/4 of a human's total calorie depletion at rest. That adding machine on your shoulders runs on glucose more than anything else.