Possible Alien Life

[CraigD]

I'm not saying that another conceivable intelligence will follow the same path, but maybe a non-specialised design provided the environmental pressure to evolve intelligence in order to make up for it, and maybe the concept might be appliccable to other planets?

 

Thoughts?

I agree with you for the most part but humans are extremely good at long distance running. A man in good condition can run longer than almost any animal. …

I think I agree with Moontanman about the characterization of humans as physically inferior to other animals: without tools, language, or intelligence beyond what one might expect from, say, a bear, an individual human can do pretty well surviving in many habitats. In diet and physical ability, we’re not much different than several species of bear, well equipped for foraging and ambush hunting, and sufficiently formidable that only a few habitats have many top predators that would pay us much attention.

 

Humans are so physically similar to many of the great apes, it’s enticing to consider what trait resulted in us being such tremendous tool-users and builders, while the state-of-the-art for our closest relative species are termite-dipping sticks and broad leaves held overhead to deflect rain. It’s only a guess, and not an original one, but mine is that our crucial advantageous trait is our amazingly capable voice-box and related sound-making anatomy, which gives us a speaking/singing versatility matched only by some bird species. With such a organ complex, language, culture, technology, and the world as we now see it seems to me an inevitability.

 

Anatomically, human throat and vocal apparatus are very distinct from other primates, due by all appearances to our upright stance, and the resulting change in our skull/spine/trachea alignment. I suspect this was an accident of evolution, the upright stance evolving to allow us improved walking efficiency as our ancestors spread from arboreal to a pastoral niches – a lucky coincidence.

 

The question arises, then, of why that other class of life, the birds (Aves), are also not language-users/tool-maker/builders on a par with us. Although recent research shows that many bird species, such as parrots, are much more cognitively and linguistically able than once thought, unless due to human intervention, they live clearly animal, not technological lives. The obvious answer is their lack of limbs with versatile, functionally hand-like appendages.

 

So, in short, my guess as to what makes us humans the “top animal” we are, is the combination of primate bodies and bird-like voices. The rest, as they say, is history (or, rather, pre-history).

 

How something like this might play out on another earth-like (or not earth-like) planet is, I think, anyone’s guess. I’d expect any alien creature with human-like technology to share our excellence at communication over long distances (our voices) and manipulating stuff (our hands), and possibly being physically formidable enough not to be gobbled up by predators (being among the largest animals in our local habitat).

[Moontanman]

Maybe part of how we evolved had to do with us migrating out of Africa where there were top predators that could kills us rather easily to more northerly climes where predators weren't so fierce. Of course it could be that we eliminated the competition by killing other top predators also. Both ideas seem to have pretty much equal footing. alien life could follow the same pattern and so look at least something like us. hands, eyes on a movable head, upright stance. But I would be amazed if they were built like us internally. Vertebrates were not a done deal when they first developed. I think the first example of a vertebrate was called pica or something similar and looked a lot like an amphioxus. Just a slight shift in evolution would have eliminated such a tiny defenseless creature and then no back boned animals at all. maybe exoskeleton animals would have made it big by evolving a better lung system. There was a millipede that was as long as a cow when land animals first came ashore. such creatures were eliminated by internal skeleton animals.

[Boerseun]

Interesting take on skeletons, moontanman.

 

However it pans out, I think that UncleAl (in his first post in this thread) hit the nail on the head for requirements, amongst them a sense organ cluster in some sort of 'head', in other words, critical senses like hearing and sight located close to the brain to speed up resonses. This is the norm across a wide variety of unrelated animals on earth, and might be a sensible adaptation in alien life, too.

 

That being the case, any sort of nervous cluster needs protection. That might require a skull of some sort. Alternative examples without skulls certainly exist, like octopi, for instance, but a brain can only grow so large and still be flexible. I'm not saying it's not possible, but still...

 

Sea-dwelling creatures can cope quite comfortably without a proper skeleton, with water supporting their bodies. But if animals were to conquer the land, which might be a prerequisite for technology to develop (what with fire, etc.), some sort of structural support will be necessary. Exoskeletons might be limiting in terms of growth and breathing. An insect cannot expand its chest cavity to facilitate mechanical breathing, rather, it depends solely on the slow diffusion of oxygen through the trachea. This places an upper limit on size, which, in turn, places an upper limit on the size a brain might achieve. So, whilst any conceivable alien's skeletal structure would look vastly different to ours, I think having an internal skeleton which includes a structural support for a nerve center which hosts critical sense organs close by (like a head) being the norm amongst technologically-able aliens, might be a big possibility. Or maybe I'm blinded by my chauvinisms...

 

I love this thread, though!

[Moontanman]

Interesting take on skeletons, moontanman.

 

However it pans out, I think that UncleAl (in his first post in this thread) hit the nail on the head for requirements, amongst them a sense organ cluster in some sort of 'head', in other words, critical senses like hearing and sight located close to the brain to speed up resonses. This is the norm across a wide variety of unrelated animals on earth, and might be a sensible adaptation in alien life, too.

 

That being the case, any sort of nervous cluster needs protection. That might require a skull of some sort. Alternative examples without skulls certainly exist, like octopi, for instance, but a brain can only grow so large and still be flexible. I'm not saying it's not possible, but still...

 

Sea-dwelling creatures can cope quite comfortably without a proper skeleton, with water supporting their bodies. But if animals were to conquer the land, which might be a prerequisite for technology to develop (what with fire, etc.), some sort of structural support will be necessary. Exoskeletons might be limiting in terms of growth and breathing. An insect cannot expand its chest cavity to facilitate mechanical breathing, rather, it depends solely on the slow diffusion of oxygen through the trachea. This places an upper limit on size, which, in turn, places an upper limit on the size a brain might achieve. So, whilst any conceivable alien's skeletal structure would look vastly different to ours, I think having an internal skeleton which includes a structural support for a nerve center which hosts critical sense organs close by (like a head) being the norm amongst technologically-able aliens, might be a big possibility. Or maybe I'm blinded by my chauvinisms...

 

I love this thread, though!

 

Actually some insects do indeed expand their exoskeletons to facilitate breathing. Have you ever observed hornets at close range or wasps? I have many times, a few times too many actually but when you finally get to where they tolerate your presense you can actually see them expanding and contracting their abdomen at a fairly high rate of speed. maybe two or three times a second. They do it by expanding the segments of their abdomens. They are pumping air in and out of thier trachea. Very facenating if you can get close enough to see it with out being stung to death! I have a porch where hornets and wasps make their nests ona regular basis and if you keep confronting them as they build their nests but don't harm them they will eventually ignore you and you can get a very close look at them.

 

Michael

[Dracontes]

I think life elsewhere on the Universe will be carbon-based. That's a given since element abundances in the universe give carbon the upper hand over silicon. I've heard that silicon life is improbable not only because silicon is easily sequestered in silicates by oxygen but also because silicon hydrides tend to be more unstable than hydrocarbons at room temperatures, specially ring structures, as the smaller covalent bond strength is more often than not trumped by bond stress (or so my organic chemistry would tell me).

 

That aside, I find it rather limiting in this type of speculation to think only of DNA as an self-copying information-storing polymer. Given the world that is organic chemistry one could find at leisure many more alternatives to your run-o'-the-mill nucleotides (the same for proteins, amino acids and lipids).

[Moontanman]

I think life elsewhere on the Universe will be carbon-based. That's a given since element abundances in the universe give carbon the upper hand over silicon. I've heard that silicon life is improbable not only because silicon is easily sequestered in silicates by oxygen but also because silicon hydrides tend to be more unstable than hydrocarbons at room temperatures, specially ring structures, as the smaller covalent bond strength is more often than not trumped by bond stress (or so my organic chemistry would tell me).

 

That aside, I find it rather limiting in this type of speculation to think only of DNA as an self-copying information-storing polymer. Given the world that is organic chemistry one could find at leisure many more alternatives to your run-o'-the-mill nucleotides (the same for proteins, amino acids and lipids).

 

I agree that limiting ourselves to DNA might cause us to miss life but to limit our selves to carbon might do the same thing. Silicon is less than likely due to more than atomic abundance. If life with some odd element is possible then the universe is big enough for it to occure eventually. Boron, nitorgen/phosferous, maybe even sulfer. In "The Deep Hot Biosphere" Gold mentions the possibility that under different pressures and heat ranges silicon might react quite differently than it does at temps ancd pressures we are familiar with and so might other elements. Recently there was a star discovered with a planet that was so hot it had titanium gas as part of it's atmosphere. What might exist on a planet with an atmosphere so hot sulfer might be a gas and silicondioxide a liquid. We can't even speculate with any real accuracy what chemical reactions might take place under hyper pressures and temps. All we can say is that if it's possible then the universe is big enough for it to occure. Maybe when we look for life we should be looking for chemicals or objects that decrese the entropy around them and in so doing make a copy of themselves.

Michael

[CraigD]

I agree that limiting ourselves to DNA might cause us to miss life but to limit our selves to carbon might do the same thing. Silicon is less than likely due to more than atomic abundance. If life with some odd element is possible then the universe is big enough for it to occure eventually.

Indeed. What’s more, under some scenarios, “eventually” might be much sooner than one might think.

 

I’m reminded of Robert Forward’s 1980 novel “Dragon’s Egg”, which describes a ecosystem on the surface of a neutron star, where, despite some relativistic slow-down, chemical reactions (including those responsible for though in intelligent animals) occur about 1 million times faster than in the rest of the low-gravity universe, and are very odd. This 1-year:30 second ratio makes for difficult communication, and a multi-generation history from pre-history to advanced technology spanning 6000 years:2 days.

 

:hihi: I consider "Dragon’s Egg" required reading for exobiology enthusiasts.