The Evolution of Outer Space Aliens

[Dis]

Re: Re: Re: The Evolution of Outer Space Aliens

Originally posted by MarkG
can you imagine an elephant trying to light a fire?

which brings and important argument to light. Along with intelligence, proper motor skills are needed to advance. Hence, why I do not like insect like races as seen in Independence Day. Opposible thumbs are needed at the very least

[Geronimo]

Re: Re: Re: Re: The Evolution of Outer Space Aliens

Originally posted by Dis


which brings and important argument to light. Along with intelligence, proper motor skills are needed to advance. Hence, why I do not like insect like races as seen in Independence Day. Opposible thumbs are needed at the very least

IIRC the independence day aliens had opposable thumbs on 3 fingered hands. Remember the captured one holding that area 51 scientist/technician guy up by his throat while psychically making him speak for it?

[Dis]

I stand corrected. Maybe Indepedence Day is a better movie than I give it credit for.

[FrostyBoy]

Btw Dis, she's faking it.

[Patroklos]

As individuals, most likely not, since there is not enough space for the computing power needed. Perhaps the colony of such beings could achieve some levelof sentience (I forget which Sci fi authors have writen about that)

Like the Buggers from the Ender stories.

An example of speculation on an insectoid type lifeform. The were not insects persay, they had evolved into a warm blooded species with the characteristics you guys are saying would be required, like lungs but retaining many of their isect like characteristics. They looked like insects.

It also had a mechanism like Geronimo was talking about that made collective intelligence possible (Hive mind they were, an intelligent queen with indiviuals as controled drones). They called it an ansible, but it was just a means to make communication instantaneous.

All stories of course, but still fun to think about

[DaShi]

Originally posted by Kuciwalker
Are you so sure of that? You can get a bacterium to make pretty much any protein - as long as you don't want it to be making lots of other ones too.

(Also to Geronimo)

That's not true. Bacteria can make a few eukaryotic proteins. And many of them are stripped down versions. Also, they can only make one maybe two of those per bacterium. They lack the size to contain enough DNA to make them. They also lack the organelles necessary for modifying and finishing those proteins. And they can't get such organelles, because they are no bigger than them.

Bacteria are simply too small to take the role of complex animal cells.

[Geronimo]

Originally posted by DaShi


(Also to Geronimo)

That's not true. Bacteria can make a few eukaryotic proteins. And many of them are stripped down versions. Also, they can only make one maybe two of those per bacterium. They lack the size to contain enough DNA to make them. They also lack the organelles necessary for modifying and finishing those proteins. And they can't get such organelles, because they are no bigger than them.

Bacteria are simply too small to take the role of complex animal cells.

Bold claims.


E-coli already comfortably fits a genome of about 4×10^6 bp whereas the entire human genome is about 3×10^9 bp

About 98% of human the human genome is non-coding or effectively non-coding DNA (introns and transposons and possible chromosomal structural elements) so lets call it 6 x 10^7 bp for the entire human genome.

Only a fraction of the genome is expressed in any given somatic cell. If you want to insist that the prokaryotic sized "neurons" use the same proteins as human neurons and also contain all of the coding genome expressed in human neurons while containing no more DNA than E-coli this could be achieved by a 'gene winnowing' process similar to that used in gene rearrangement in human b-cell precursors. Instead of retaining all coding DNA in all cells it would be retained only in (possibly much larger) germ line cells and snipped out at various stages of differentiation as the cells commit to fates where those genes will not be expressed. The resulting cells would contain all of the genes expressed in a human neuron while having roughly the same DNA content as an E coli.

Entire organelles are not necessary to modify any proteins. Instead particular chaperone proteins or similarly sized binding sites on other macromolecules participate in modifying the proteins.

This has all been generously assuming that you can only have the functional equivalent of a human neuron if it contains functional equivalents for all of the proteins present in a human neuron AND assuming that you require as much genomic material as human neurons use to accomplish this AND assuming that prokaryotic sized cells can't accomodate a longer genome than e coli can.

I don't see why we should hold such assumptions when speculating about alien life forms.

[Q Classic]

Is it not entirely possible that any aliens evolving elsewhere would be sufficiently alien that they would be somewhat unrecognizeable to us?

[Geronimo]

Originally posted by Q Cubed
Is it not entirely possible that any aliens evolving elsewhere would be sufficiently alien that they would be somewhat unrecognizeable to us?

Superficially certainly.

Do you mean that some could be so alien that we would never even be able to identify them as life forms? I don't think there is any testable definition of life that would hold true for indefinitely no matter how alien they might be.

[Kuciwalker]

Originally posted by Geronimo
That's not at all clear. Do you believe that greater complexity only evolves as a consequence of selection for new capabilities?

Greater complexity has a huge cost. It would only be successful if it conferred additional abilities as well.

[Q Classic]

Originally posted by Geronimo


Superficially certainly.

Do you mean that some could be so alien that we would never even be able to identify them as life forms? I don't think there is any testable definition of life that would hold true for indefinitely no matter how alien they might be.

That's not what I'm saying. I'm saying that they may be so alien that while they may have processes for respiration, it may not be something we'd be initially looking for.

[Geronimo]

Originally posted by Kuciwalker


Greater complexity has a huge cost. It would only be successful if it conferred additional abilities as well.

It depends on the nature of the complexity. White noise is a lot more complex than a human voice but it can hardly be claimed to be more costly to produce.

[Geronimo]

Originally posted by Q Cubed

That's not what I'm saying. I'm saying that they may be so alien that while they may have processes for respiration, it may not be something we'd be initially looking for.

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.

[Kuciwalker]

Originally posted by Geronimo
It depends on the nature of the complexity. White noise is a lot more complex than a human voice but it can hardly be claimed to be more costly to produce.

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

[Vesayen]

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.

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.