This guy I know on YouTube, Phrenomythic, just uploaded a video, Humanoid Aliens: How plausible are they?, and I said to myself, “Hey, didn’t I give a talk on a similar subject years ago?”, and I did! Not only did I, but I had the presentation and my notes neatly filed away, so I decided to just redo the whole thing and put it online again — I think it holds up.
Pharyngula
Evolution, development, and random biological ejaculations from a godless liberal
Aliens would be stranger than you imagine
Heck, I thought you were talking about people from the USA.
If you want a hint of what aliens would be like, just take a look at mantis shrimp.
How about those weird, tetrapod-adjacent, deep-water sea cucumbers, the ones sometimes called “sea pigs”? Closest thing to aliens so far.
The aliens in Peter Watts’s Blindsight seemed pretty weird to me, but it turns out that they were based on brittle stars. Given that Earth’s biosphere has produced a whole load of really weird organisms that no-one would believe if they weren’t real, coming up with realistic aliens is hard!
I’m not in a position to watch the video yet, but…. doesn’t parallel evolution suggest that life would at least be similar even on other planets? If Australia and Norway can both get the bat wing, or the burrowing claw, or whatever, doesn’t that show that life generally follows basic patterns of development no matter where it is? Sure, there would be differences due to variables of gravity, air density, etc, but whatever works, works, regardless of the setting.
We might look at examples like the mantis shrimp or sea-cucumber for “weirdness”, but even other planets are bound to have analogies to these living in their oceans, without suggesting that they would be the model for intelligent life with highly-developed cerebellums. You can’t just stick a reasoning brain into a shrimp’s body and call it an “alien”. A sentient brain capable of technology and poetry still needs an adequate support system.
Even technologies would seem to evolve in parallel. A burgeoning alien civilization would still need to discover the hut, the spear, the internal combustion engine. They aren’t likely to have wildly different ways of living, just because their planet isn’t named “Earth”. The universal properties of physics are still going to dictate biology, no matter where they are applied.
edmond @5: A Wankel design internal combustion engine is different from a piston design; throwing spears won’t get much use if the physiology of the alien means they can’t throw spears (maybe they’d be happier with bolas?); while the existence of huts is kinda contingent on a bunch of social and biological factors, not to mention that even human dwellings come in a variety of types.
As you say, whatever works, works; but Earth life _hasn’t_ explored all the possible solutions to living, and some possible solutions can’t be found starting from modern Earth life, because our development has cut off those options.
I have not watched the video yet too, but @edmond, the “bat wing” is not a universal thing. “Wing” might be universal thing, but here on earth we have at least four different types of wing that evolved completely independently of each other and look very differently (bat, bird, insect, draco volan).
Locomotion by using appendages is not a universal thing either, neither is internal skeleton, bilateral symmetry etc. etc.
As a matter of minor pedantry, David Ike’s last name is a monosyllable, pronounced to rhyme with “spike”, not a two-syllable work rhyming with “sticky”.
I think the best treatment of aliens that I have ever run across in print is David Brin’s Uplift series. He not only has different body types (though one of the main allies of the wolflings (us) are a species that is superficially humaniod), but uses breeding strategies, ancestral biological niches, and religions to bring out the different modes of thought rather than assuming that all aliens are basically humans no matter what their body design. There are even hydrogen based life forms who live in very slow motion, and machine intelligences who have agreed to limit breeding in order to be acceptable to oxy-life.
But yeah, most aliens in fiction are humans in costume.
Thanks for the presentation.
A more genteel name of that hand signal would be “the Spocker.”
NelC @6: Sure, these two engine designs are different from each other, but not “alien” different. They were still both invented by the same species. And whether a species prefers to throw spears or bolas, “throwing” is still a very basic function. I’m not talking about varieties of types like different human dwellings. We still have “shelters”, as do many animals. As any species moves into intelligence and civilization, it seems likely that there are going to be some universals.
Comparisons to potential alien life should start from “modern” Earth life. We had to get here from primitive beginnings, and so would life on other worlds. “Limbs” are likely to be common, and if they’re going to climb on land then they’re going to need a stable support system, joints, metatarsals for manipulation…. evolution stumbled onto these successes here, even on separate continents. Why wouldn’t it be just as likely to find what already works even on another planet?
Skeletons work, so even another world is probably going to have a divergence from invertebrates to vertebrates. Skin works, scales work, feathers work, big brains work even better…. if evolution is not a directed process, but merely takes advantage of the most successful systems, then those systems are likely to be similar even in different environments or conditions. Nuances of language and culture will surely be vastly different and bizarre to one another, but aliens are still going to need to communicate. They’ll find that stone can be carved into, and then that paper stacks more efficiently, for better storage and portability of ideas. They’ll discover that fire burns, and that certain chemicals explode. They’ll harness this into machines which can turn cranks. They’ll utilize that to push vehicles. Even if their physiology allows winged flight, they’ll still have to transport heavy goods. They’ll be belching carbon into their atmospheres before too long.
I think there’ll be more similarities than we might expect, both structurally and socially. Of course, we’re far more likely to discover alien life which is either much farther ahead of us, or much farther behind, than we’ll encounter beings at our exact level of development.
@Charly #7…. These four different types of wings are not so different from each other. Bat wings and bird wings share remarkable similarities. Draco volans wings are very simplistic, just gliders. And insect wings are unique to that level of evolutionary development; an alien world is just as likely to also have an insect level of species with similar wings. As we go up the evolutionary “ladder”, we don’t see insect wings being utilized by mammals. They can’t carry the weight. They’ve been discarded in larger animals. The fact that evolution has come up with four different wings doesn’t sound like an example of its boundless innovation, it’s more like an example of its limitations. Four is about all there are. The next wing to come along was the aerofoil.
Locomotion by appendage or skeletons or body symmetry work the same way. There are simpler forms of these characteristics in the “lower” life forms, but as life moves from crawling to swimming to walking to walking upright, then we do begin to see universals in how these are carried out. Other planets will likely go through a similar process of moving from the slime to the skyscraper. They will have something like bacteria, something like starfish, and something like simians. There will be surface differences (color, proportion of limb size, number of limbs, center of gravity, etc), but they will still be “animals”, with all which that entails.
The Solaris ocean is the strangest biological entity in fiction, alongside the non-biological black monolith.
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Re. wings, a high-density atmosphere might allow lighter-than-air organisms. Also, far more glide-flying animals. Non-gliding locomotion with wings require a considerable oxygen content in the air.
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Did everyone forget the pterodactyls, and the gliding animals that include snakes and squirrels?
Everyone knows that aliens will look exactly like humans, except they will have bumpy foreheads and possibly strange ears. Also all members of any given alien race will dress exactly the same.
Re. Mesozoic animals, Vivi Vajda et. al. have now dated the Chixchulub impact to 66.050 million years ago, using tektites and Ar40/Ar39 dating.
Before that, giant cows ruled the Earth (as proven by the illustrations by Gary Larson).
But maybe the more important question is what we look like to the aliens, especially if the answer turns out to be “Lunch!”
if we are just thinking about animals then looking at what has lived here in the time life has been evolving here we have an almost overwhelming variety to chose from as was indicated above.
Intelligent life would likely have to have an advantage being intelligent and a disadvantage in other aspects physically. another advantage would be an animal that is highly social and very cooperative. a smallish not particularly powerful they would not need to have any particular number of limbs nor facial structure but a creature that is highly social and clever would be needed by definition. and you probably could not get a human actor to play on in a rubber suit.
uncle frogy
Nice video! This is something I love thinking about, ever since I was young. Also, I was a big fan of Animorphs. I should probably post some of my childhood drawings of aliens on DeviantArt, along with my more recent stuff.
I like the comparison of the squid and the fish. So similar yet so different.
Some thoughts I’ve had since PZ’s post about classifying fictional aliens:
A large highly mobile creature will need to balance against gravity, and move in a direction. Bilateral symmetry is really good for this, it optimizes both of those axis (symmetry for balance, and a forward axis for motion). Even our intelligently designed vehicles have bilateral symmetry for these reasons (and often four “limbs”).
Also, earth life has already explored so many different basic body plans, from formless blobs, down to one axis of symmetry, or two axes of symmetry.
Still, someday I think it would be fun to go as hard-sci fi as possible, and try to evolve some forms either with pen and paper, or a computer simulation, all the way from a basic “one celled” organism (though even that is contingent, I always wonder if I could even go further). See what happens. Hard sci-fi is the best. It just takes more work.
But… a lesson we have had to learn over and over again is that we are not that special. Our star isn’t special, our star system isn’t special, our galaxy isn’t special, our planet isn’t likely to be that special (other than being the place we live), and so on.
There is an argument that we too, as intelligent life, are not special, and given everyone in the universe shares the same physical laws and chemical processes, and all intelligent life has to overcome the same obstacles and challenges to make far enough to make first contact, I suspect we will surprised at how similar we are, if not quite to the same extent as the various alien races in Star Trek.
Then perhaps nobody joins the greater Galactic Commonwealth until they have evolved beyond their biological selves. After all, meat bags are not that convenient when it come to the rigors of interstellar travel. Maybe the only intelligent biological aliens left are the galactic equivalent of the Amish, sticking to the old ways in some quiet corner of the outer spiral arm as the machine culture continues to expand and thrive elsewhere…
Oh, and having advanced sensors able to inspect stuff that goes into the mouth seems really useful. Breathing through your eating area and choking to death, not so useful (but, interestingly, evolution didn’t weed out this defect).
tacitus:
1. We might not be special, but surely we’re different, given the contingencies of our particular environment and deep history.
2. Nonsense. The possibility-space of all environments greatly exceeds the that of environments like ours, and the particular “obstacles and challenges to make far enough to make first contact” greatly depends on the particular environment.
3. Even in Star Trek, there were non-carbon-based inscrutable life forms. But yeah, mostly people who were basically humans with lumpy foreheads. Realistic, that.
<snicker>
Fair enough. The answer to the Fermi Paradox is that there are no GAIs on Earth to draw forth the emmisaries of the Commonwealth.
(Way to think like an ape)
ook
“Take me to your leader” :)
John Morales:
or if they happened upon Schubert:
“Take me to your lieder”
Oh, I don’t know about that – there are some pretty weird entities in Iain M. Banks’ The Algebraist, including one that is basically a vast could of interstellar gas, only marginally denser that the surrounding interstellar medium, and which operates on timescales so slow that just to say hello to it takes months.
Banks makes a couple of interesting points in that book… Firstly, a lot of it revolves around the idea that different species perceive time at different rates, and this changes how they perceive things like interstellar travel – so the gas-giant Dwellers, who operate much more slowly than humans and live for billions of years, have no trouble with the idea of making interstellar journeys at relatively slow speeds, because the time it takes them to travel to the next star system at 1% of c is just long enough to read a good book and have a bit of a nap.
The other point he makes is that different species types effectively inhabit different galaxies, because they have radically different environmental requirements, perceptions, and time scales. To most of the Dwellers, humans (and other similar species) may as well not exist.
Here’s a neat video showing computer simulated evolved soft-bodied things that are adapted for movement.
Now for some differences instead of similarities: this website about “bizarre” and “strange” animals. I suspect that familiarity is a factor, otherwise I’d swear that giraffes should be listed there. But they do list platypuses! It’s a must.
Another crucial thing: photosynthesis. Pretty important to get a planet full of life, I think.