What Will Aliens Look Like?

[Queequeg]

Inspired by the small Starship Troopers discussion and this.

The link is really pretty interesting for anyone with any interest in paleontology, as you'll instantly recognize a lot but there are some clever (and occasionally disgusting, like the second head/penis thing)differences. 

But I'm curious.  We have an amazing history here on earth of convergent evolution, but do you think this would apply to other, presumably reasonably similar planets?  Are we going to find streamlined animals in oceans with bodies like dolphins or tuna and ichthyosaurs, and large back-boned creatures on the shores? Or a bunch of blobs? 

Can we know anything?

[Jaron]

[HisMajestyBOB]

Depends; intelligent life (meaning "capable of building a civilization") will likely look more similar to us that one might expect - likely omnivorous, opposable digits, symmetry, possibly bipedal. Other life may look weirder, but in all likelihood should look like something that could have evolved on earth. Except for extromophiles - those things will always be freaky.

At least, in my opinion as someone who's knowledge of biology can charitably be called "lacking".

[jimmy olsen]

Keep moving into my territory and I'll break your legs.

Sincerely, Mr. Olsen. 

[Queequeg]

This is speculative zoology, and therefore within my domain.  Might as well be "what will animals look like after us, or if we had not evolved, or all died off tomorrow?"

[DontSayBanana]

Tim's got far-flung speculative "science," as well as alt-history preferences...

I recommend this thread be redone as mad libs, with Timmay drafting the bulk and Spellus calling out random esoteric animals and archeological sites.

[Alatriste]

They will look... well, they will look really alien. One doesn't need to go further than the deep sea to find living organism far stranger than anything writers have imagined (and we really should remember than statistically the most typical place on Earth is an abyssal plain, silent, cold, dark and under extremely high pressure).

There will be some things, however, that will work more or less the same. Where there is an ocean streamlining will force a clear similitude, for example, and flight (provided roughly Earthian gravity and a dense atmosphere) will still require wings and light bodies. 

[Faeelin]

They will look... well, they will look really alien. One doesn't need to go further than the deep sea to find living organism far stranger than anything writers have imagined (and we really should remember than statistically the most typical place on Earth is an abyssal plain, silent, cold, dark and under extremely high pressure).

Two nitpicks here. First, I suspect most biomass is not on the silent, cold abyssal plains.

Second, of course life in radically different environments will look different. But take a temperature 1g planet with the same rough mix of atmosphere as Earth. How different will that be? That's teh real question, IMO.

[Queequeg]

I think an interesting question there, Faeelin, is how much impact seemingly slight variations in environment can effect life on earth?  For instance, if a relatively slight variation in atmospheric oxygen content is the difference between the Devonian's world of massive arthropods, the Jurassic's titanosaurs and our modern dearth of true megafauna (at least, to the extent that that is not the result of anthropogenic extinction).  Surely this would be just as true on other planets, with other variations we can't really fully comprehend.

[Alatriste]

They will look... well, they will look really alien. One doesn't need to go further than the deep sea to find living organism far stranger than anything writers have imagined (and we really should remember than statistically the most typical place on Earth is an abyssal plain, silent, cold, dark and under extremely high pressure).

Two nitpicks here. First, I suspect most biomass is not on the silent, cold abyssal plains.

Second, of course life in radically different environments will look different. But take a temperature 1g planet with the same rough mix of atmosphere as Earth. How different will that be? That's teh real question, IMO.

About biomass, I'm not so sure... you can be right, but life on the surface is a very thin but 'life dense' layer. On the abyssal seas, the equivalent is hundreds or thousands of meters thick. I don't even know if we have any serious, reliable study regarding total biomass in the deep seas environment. Life is certainly scarce there in life forms per cubic meter, but total biomass... who knows?

Regarding Earth-like planets, 1g, 290º K, nitrogen-oxygen atmosphere... well, the closer we have to another planets are independent land masses with long periods of independent evolution, like Australia. Not the same thing, of course, but the Australian example seems to teach that both examples of convergent evolution (like the Tasmanian wolf, a marsupial) and of different, exotic life forms (kangaroos, platypus) will exist.

[Darth Wagtaros]

Mostly humanoid, maybe some ridges on their faces.

[Neil]

Could be just about anything, really.  Physics and evolutionary utility put some limits on there, but it's difficult to say without a more detailed understanding of their environment.

[grumbler]

Mostly humanoid, maybe some ridges on their faces.

You mean:

[Alatriste]

Mostly humanoid, maybe some ridges on their faces.

You mean:

Could pass for an Earthling of the 1980s if it weren't for an small detail. Only an alien would choose that tie... 

[Razgovory]

Depends.  The good ones will look like insects or spiders or something.  The good ones mostly humanish.