I mean is it not logical to assume that any intelligent alien life we find will have some kind of digits? After all without fingers it might be hard to make tools and evolve. What about the type of animal they are. Is it plausible that an animal other then a predator evolve to be intelligent? What about non social animals? Could they ever perceive to build a society if they were non social intelligence aside?
We already have a good example of an alien life form that migrated to Earth. Here’s a rare image of it pining for home.
Astrobiology is as yet a purely speculative “science” with no subject matter to work with. All we really have are artists’ conceptions, some of them scientifically impossible or at least implausible. (Telepathic Slavers?)
How dare you make fun of my man Denny!
With no data we can only speculate. With no real hope of getting data, we can make only idle speculation.
That being said, I suppose we can presume bilateral or radial sementry. <== A word I cannot spell well enough for the computer to help me.
All large animal we know of exhibit one or the other.
This one is trying to look like a human female , but not very convincingly.
[yoda voice]
Sementry. Like it you might.
[/yoda voice]
I see no reason to presume that evolution would cause the same pattern of changes in the same order as occured on Earth before multicellular life began speciation. A trait that manifested itself in our eucaryote ancestors through a specific set of circumstances may not manifest in organisms on another planet at all, or in the same way, where the environment, no matter how similar to ours, will be different.
So no, I don’t believe alien life would look anything like us, although their biology would provide a means for overcoming the same obstacles ours does, e.g.: perception, locomotion, procreation, etc…, just in different ways.
Sure, we can’t know for certain, but speculation can be fun.
I like Barlowe’s Expedition (Inspiration for the I-must-still-see Alien Planet Discovery series) better than the Guide, mostly because some of the Guide drawings really don’t agree with my own mental versions of the relevant aliens, and also because Barlowe tried for some rationale or consistency behind the ecosystem he created for Darwin IV
I don’t think that we can even assume that we’d be able to see an alien life form. Who’s to say that they’d be carbon based? They could be made out of energy, they might be made out of xzytyzuhghhix, which of course is a possible building block of alien life.
They might even be to large or to small for us to see. It boggles the mind!
I’ve been meaning to ask this question for a long time.
Surely we can establish some constraints? For examply, they couldn’t be larger than a certain size (assumming their gravity is similar to ours), and if we’re assumming that they are as roughtly as technologically advanced as we are, then they would have to be at least a few feet tall, with opposable “thumbs”.
I have no idea about bilateral symmetry. There’s no reason to assume that they would have it, just because most animals on our planet have it. But what other options are there? A spaceship driving starfish? I can’t see it.
Would something like a centaur be possible, with 2 sets of limbs suitable for walking and 1 (or 2, why not?) suitable for grasping tools?
Would they necessarily be warm-blooded?
Would it be possible that they are more like plants? Could an alien “animal” get its energy from photosynthesis?
ISTM that if they’re not as intelligent and advanced as humans, then there’s no telling, since there are no constraints.
ETA: by “like a centaur”, I simply meant “having more than 4 limbs”. Not “half human, half horse”.
That presents certain practical problems . . .
I very much doubt a microscopic organism could be intelligent. Brains have to be made of matter; atoms and molecules have a definite minimum size and only so much complexity is possible at the level of viruses and bateria.
Or was that a whoosh? We’re in a field, here, where it’s really hard to tell.
I’ve toyed with an idea about a planet where six limbs, not four, is the typical form for the nearest analogue of vertebrates – meaning any branch of the family, strictly needing only four limbs for locomotion, can potentially develop its front two limbs into manipulative organs without the extremely rare and difficult happenstance of evolving fully bipedal locomotion (that’s only happened twice in Earth’s history – to dinosaurs and to hominids), possession of which manipulators infers a differential survival value in direct proportion to the sophistication of the neural equipment available to make use of them; meaning some measure of intelligence, about that of your average primate, would be the norm for hexapod vertebrates, and there would be multiple fully sentient species coexisting.
Well, a great deal of life on Earth resembles Insects, Crusteacians & Arthropods.
So, good odds we’d get centipedes/scorpions the size of your arm.
I’m assuming you’re including birds as a subset of dinosaurs. But there’s also the Macropodia.
But the dinosaur thing should convince you that having forelimbs that aren’t dedicated to walking doesn’t do much to increase intelligence. There were hundreds of bipedal dinosaur species with “hands” of various sorts, and all of them had really really small brains, even the dromeosaurids.
And kangaroos aren’t known for their smarts.
Elephants are an example of a really smart herbivore, that should put to rest the notion that it doesn’t take intelligence to sneak up on a blade of grass. Plus elephants have perfectly fine manipulatory organs despite being quadrupedal.
If we look at the body plans of really smart earth animals, you can see primates, proboscideans, carnivora, cetacea, pinnipeds, corvids, and parrots, plus cephalopods I suppose…no one knows how smart those 2 meter ammonites were.
And none of the other really smart animals resemble humans much, if we exclude the primates. Raccoons and otters and elephants and cephalopods have pretty good hands, but dolphins and whales and seals and pigs don’t. Parrots don’t have hands, but they have amazingly agile beaks and tongues. It seems to me that hands don’t neccesarily lead to intelligence…there are plenty of rodents and marsupials that aren’t particularly smart but have pretty good hands.
As for symmetry. Well, the first form of symmetry is spherical symmetry. But with gravity, you’ve got a top and bottom, and that gives you radial symmetry. But if you’ve got sense organs and a nervous system, it makes sense to cluster the sense organs near the food-grabbing organs, and cluster the nerve ganglia near the sense organs, and put the excretory organs on the opposite side from the eating organs, and now you’ve got bilateral symmetry just out of gravity and cephalization.
Other than that, it’s wide open. If we take the history of earth animals as a starting point, we can imagine all sorts of intelligent creatures that have body plans somewhat similar to ones that actually existed on earth. Even if they don’t have hands. I mean, would you expect dolphins to be particularly intelligent, with absolutely no manipulative organs? Yet they’ve got brains bigger than human brains.
E.g., the tyger.
That depends entirely on how broadly you define “digits”. It’s very easy to imagine an animal like a catfish with thousands of tentacles growing out of its chin that would have much more dexterity than a human. The tube feet of a starfish could easily serve the same purpose. Even more remotely we could envision an animal that is able to manipulate its own integument to produce pseudopods at will.
So no, digits are not in nay way necessary for dexterity, much less intelligence.
Very plausible. Look at elephants.
Yes, just because species is non-social doesn’t mean they are non-cooperative. Animals of totally different species re perfectly capable of cooperating for common benefit without being social, so there is no reason why a non-social animal couldn’t achieve civilisation. In fact I could make a good argument that a non-social animal would achieve civilisation faster.
Radial symmetry seems unlikely since it precludes cephalisation, and hence no brains. Those animals on Earth that have reverted to radial symmetry have inevitably lost their brains as well.
Bilateral symmetry is likely because you need symmetry in early development to get any benefit from cephalisation and you need cephalisation to get intelligence, at least with a physical form. However it’s not true to say that all large animals are bilaterally symmetrical. Many animals such as flounders have lost any trace of such symmetry and there is no reason to presume that doing so would affect intelligence.
Nope.
Why? What would be the size constraint of an animal bouyant in a sea of molten iron? There might be some size limit but it would be many millions of tonnes.
As I already noted, they wouldn’t even need digits, much less thumbs.
As for size, why couldn’t an intelligent creature be the size of a wasp? We are limited because our brains are cellular in design and so our intelligence is limited to the number of cells we can cram into our heads. There is absolutely no reason to even assume cellularity in other creatures, they could be syncitial or totally acellular. There is even less reason to assume that their sensory processing occurs through cellular a mechanism rather than a simply chemical or electrical system. If that were the case it could be orders of magnitude smaller than out own meat boxes and capable of fitting inside a creature the size of a mouse or an insect.
There is actually a very good reason to assume it. If you are radially symmetrical there is no advantage in clustering your sensory processors in any one place because input comes equally from al directions. Only after you develop preferential directional locomotion can you benefit from clustering your processors in the direction of motions. Once you develop preferential directional movement you will inevitably develop bilateral symmetry.
No.
Not as we know it, no. In an extremely radiation rich environment an animal could get energy through photosynthesis and remain fairly mobile and intelligent, but that would be nothing like photosynthesis as we know it.
If that’s what all their women look like, I suggest that we implement a cross breeding program immediately.
There are some things that might constrain the size of individuals in a technological race - fire, for example, doesn’t scale up or down with linear effect - so an ant-like creature with human-equivalent capacity for intelligence (on a planet with broadly earth-like conditions) would not be able to build a tiny charcoal furnace and smelt tiny ingots of iron - it just doesn’t work that way. I suppose a colony of such creatures could work together, forming a meta-organism that would be capable of manipulating fire big enough to smelt metals, but then in a way, that meta-organism is the individual unit.
Water is another one - at tiny scales, surface tension and viscosity makes it behave quite differently, so a tiny ant watermill isn’t possible, at least not anything that closely resembles a human-scale watermill.
Of course there are other fluids, other working materials, other possible planetary conditions, and you don’t have to smelt metals, or extract power from running water (but if you can, it helps).
So… I don’t think we can necessarily predict how things must be elsewhere, but amongst the spectrum of all possible behaviours and outcomes, some are naturally more easily exploitable than others, and life, especially intelligent/technological life, is quite likely to nestle into those comfy spots, but not necessarily the same comfy spots we’ve nestled into.
I think you skimmed your own Wikipedia cite far too fast. The first sentence of the overview says very clearly:
There’s also a lot more to astrobiology than just sitting around imagining whether green-skinned Orion slave girls actually exist, you know. Right now, most of it is fundamental work understanding the myriad of conditions under which microbial life could have developed, or exists now. Have a closer look a the methodology section of your cite for a few details.
While it might sound edgy to diss the field, the “criticisms” section is rightly flagged because it’s mostly a steaming pile of BS. In fact, it’s a perfect example of why Wikipedia can be such a lousy sole source of info on any topic.