The Evolution of Outer Space Aliens

[Geronimo]

Originally posted by Kuciwalker




The difference in complexity between eukaryotes and prokaryotes is one that requires massive amounts of additional resources to sustain.

How much of that is simply because Eukaryotes are so much bigger? In the world that eurkaryotes and prokaryotes arose from size would have had a quality all it's own. Certainly it would have offered access to a new niche. It's not easy to drastically increase the size of a cell. You can't simply scale everything up you need to reorganize largely because of huge surface to volume issues.

Another obvious source of complexity seems to be endosymbiotic evolution. Endosymbiotic evolution may confer new capabilites on the receiving cell but the ability itself originally belonged to the tiny free living prokaryotic cell. Post merger, the combined cell is a far more complex cell, but it doesn't really posses new abilities that couldn't be found in the simpler prokaryotic precursor, apart from the aforementioned size.

[Geronimo]

Originally posted by Vesayen


You are saying that the problem is we may not recognize things as life because they do not fit our definition of life.

Then... isn't the issue that we need to expand our defenition to be broader?

I don't think this would be a problem, we know life when we see it, because we know complex chemical processes when we see them.

it would at least make us suspicious I'll concede that.

[Kuciwalker]

Originally posted by Geronimo
How much of that is simply because Eukaryotes are so much bigger?

Some amount, obviously. But if several prokaryotic cells could perform the function of an equal-mass or equal-volume eukaryotic cell, such would exist. It doesn't therefore they can't.

[Geronimo]

Originally posted by Kuciwalker


Some amount, obviously. But if several prokaryotic cells could perform the function of an equal-mass or equal-volume eukaryotic cell, such would exist. It doesn't therefore they can't.

How far do you take this reasoning?

If reptiles could be as intelligent as humans, such intelligent reptiles would exist. They don't therefore they can't?

[lord of the mark]

Originally posted by Sn00py
Spore will reveal all!

this is just viral marketing for Spore, isnt it?

[Dis]

Originally posted by Geronimo


How far do you take this reasoning?

If reptiles could be as intelligent as humans, such intelligent reptiles would exist. They don't therefore they can't?

not necessarily. Aren't mutations the main reason humans exist? Which means it was just a matter of luck we are here today.

[Geronimo]

Originally posted by Dis


not necessarily. Aren't mutations the main reason humans exist? Which means it was just a matter of luck we are here today.

it sounds as if you agree with me that we shouldn't rule out the possibility of something evolving even if it hasn't been observed on earth. Did I miss-read you?

[Dis]

I agree. Most scenarios are unlikely on earth, but I can't see why conditions on other planets wouldn't have different evolutionary paths.

the real question is why aliens from other worlds have no problem adapting to earth environment (and vice versa).

And why did Captain Kirk never get any nasty STD's?

[Geronimo]

Originally posted by Dis
I agree. Most scenarios are unlikely on earth, but I can't see why conditions on other planets wouldn't have different evolutionary paths.

the real question is why aliens from other worlds have no problem adapting to earth environment (and vice versa).

Some aliens might find earth conditions survivable but it would be very hard to intelligently guess how often that would be the case so sci fi writers just assume whatever is convenient to their story. Sometimes they portray the aliens as unable to survive direct exposure to earth conditions (The Tripods for example) but usually they just portray them functioning freely directly exposed to the earth environment.

About the same ratio of can tolerate/can't tolerate local environment seems to apply to sci fi humans on alien worlds.

Originally posted by Dis
And why did Captain Kirk never get any nasty STD's?

It would have made as much sense as human-alien hybrids and we were shown plenty of those. I guess McCoy had some potent 23rd century solutions to such problems that tactful respect of patient doctor confidentiality kept off-camera.

[FrostyBoy]

Originally posted by lord of the mark


this is just viral marketing for Spore, isnt it?

I hope this cheque from a Maxis clears.

[Q Classic]

Originally posted by Geronimo


So you're concerned that our definitions of life and of things associated with life may be too narrow to include alien equivalents that we might therefore fail to recognize. I think this thread helps illustrate how easily that could occur.

Precisely. Here we are, talking about the difference between prokaryotes and eukaryotes, or between insects and mammals and sizes, seemingly without considering that different evolutionary pressures on a different planet may have made things develop in an utterly alien fashion.

See how I worked "alien" in there? There's a reason for that.

[Q Classic]

Originally posted by Vesayen


You are saying that the problem is we may not recognize things as life because they do not fit our definition of life.

Then... isn't the issue that we need to expand our defenition to be broader?

I don't think this would be a problem, we know life when we see it, because we know complex chemical processes when we see them.

Much of the argument here is about things that arose out of Earth's particular evolutionary pressures; while it's entirely plausible some other planet may have had similar pressures, it's also entirely plausible that a different solution may have been developed.

As far as complex chemical processes, sure. It'd be suspicious, but the traditional definition of life, as I learned it in biology not too long ago, excludes some that could pass for it--such as virii.

[Lord Avalon]

Originally posted by Dis
And why did Captain Kirk never get any nasty STD's?

Maybe he did, but the skilled Dr. McCoy cured him.

Or he didn't run across any that were able to jump between species.


Anyone remember this joke?

Rishathra?
I'm sorry, you have an insufficient number of orifices.

[Kuciwalker]

Groan. I shouldn't have gotten that.

[Kuciwalker]

Originally posted by Geronimo
How far do you take this reasoning?

As far as makes sense

In the case of bacteria, there are so many of them and they've had so much time to evolve such traits that it is unthinkable that they didn't if they could. Thus they can't.

Just like there cannot be $20 on the street, because if there were, someone would have picked it up

If reptiles could be as intelligent as humans, such intelligent reptiles would exist. They don't therefore they can't?

The grounds for that argument are weaker than the grounds for mine.