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Having read about molecular biology and so forth, I would love to be
able to simulate this kind of thing in a computer. With real organisms,
you have to guess what happened from the evidence that is left today.
With a computer simulation, you could potentially record the entire
history of the whole system.
There's a couple of problems with that though.
One problem is chemistry. In real life, the amino acid sequence of a
protein dictates the way it folds up to make a functional molecule, and
the folded shape dictates what the molecule actually does. But
currently, predicting the way that one single small protein will fold is
a computational problem so crushing that it brings state-of-the-art
supercomputers to their knees. The largest computer cluster in the
world, folding@home, exists to simulate *simplified* protein folding
experiments.
If it takes that much computer power just to calculate the shape of one
single protein, then simulating an entire living cell, consisting of
many hundred trillion protein and other molecules is obviously vastly
infeasible. Simulating a multicellular organism such as a tiny ant is
laughably impossible.
The next problem is the size of a typical genome. According to
Wikipedia, the various genomes that have been sequenced vary from 10 MB
to 10 GB of data. Now, evolution usually happens in populations of
thousands if not millions of individuals. If each individual has a 10 GB
genome and you've got a million individuals, that's 10 petabytes of
data, right there. And if you want to keep a complete record of the
genome of every single organism that has ever lived... we're easily
talking about exabytes of data here.
And then of course, there's the sheer implausibility of /creating/ life
in the first place. You might have to wait a *long* time for your
randomly mixing chemicals to do anything even remotely interesting.
Come to think of it, evolution is very, very slow anyway. To get
anything interesting, you would have to have vast environments of varied
types to inhabit, and you would have to wait a very long time.
In all, simulating life as it exists on Earth is infeasible. All the
computers on Earth couldn't handle a few microbes, never mind anything
that could be called an ecosystem.
Most artificial life simulations don't do this, of course. They simulate
a small data set, apply some kind of arbitrary "fitness" function to it,
and keep all the individuals with fitness above some arbitrary cutoff
value. They then do some kind of duplication / mutation process, and repeat.
The thing is, usually the way the fitness function is set up, there is
exactly one possible solution, and the system is so simple that there's
only a handful of ways to achieve that solution. And the whole machinery
of the system is very simple. Usually only one tiny component of it can
change.
In real living systems, on the other hand, *everything* can potentially
be modified. For example, an organism can evolve a brand new amino acid.
Not just theoretically; this has actually happened. But a computer
program that just copies a set of codes according to hard-coded rules
can't ever do something like that.
Real systems have other interesting properties. Organisms can actually
alter their environment. (E.g., Earth's atmosphere didn't originally
contain oxygen. Plants invented that.) And organisms don't just die if
their fitness is less than X, otherwise live forever. They live or die
depending on how favourable the conditions are. There are predators and
prey. There is competition for space, food and materials. All this
richness that the computer simulations almost never include.
On the other hand, I'm still at a loss for how to include all this
interesting stuff without the simulation slowing down to the point where
it's slower than *actual* evolution...
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Invisible wrote:
> One problem is chemistry.
If you haven't, you really really ought to read Permutation City by Greg Egan.
--
Darren New, San Diego CA, USA (PST)
Serving Suggestion:
"Don't serve this any more. It's awful."
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"Invisible" <voi### [at] dev null> wrote in message
news:4d3dac89$1@news.povray.org...
>
> On the other hand, I'm still at a loss for how to include all this
> interesting stuff without the simulation slowing down to the point where
> it's slower than *actual* evolution...
I remember my high school chemistry teacher once taking the time to mention
"how improbable we are". When you consider everything from getting ANY type
of life started in the first place, right up until the point where sentient
life develops, it really makes you think. I've even heard it said that
without the moon, there is no chance that humans would have developed, since
it has often protected us from asteroid impact. Every time organisms
started evolving to a certain level, BANG!
Anyway, yes. There are so many things to consider that it really makes you
wonder if we actually are alone in the universe. Perhaps the odds of life
evolving to this point are 1x10^21 to 1. I'd like to think that's not the
case, but it does make me wonder. At that point, it becomes more of a
philosophical issue, rather than a scientific one. At this point, we have
"one in a row" to work with, which really doesn't help very much.
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UncleHoot wrote:
> I've even heard it said that
> without the moon, there is no chance that humans would have developed, since
> it has often protected us from asteroid impact.
Actually, I have heard it was the moon skimming off excess atmosphere.
Otherwise, the earth would be like Venus.
--
Darren New, San Diego CA, USA (PST)
"How did he die?" "He got shot in the hand."
"That was fatal?"
"He was holding a live grenade at the time."
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UncleHoot <jer### [at] questsoftwarecom> wrote:
> I remember my high school chemistry teacher once taking the time to mention
> "how improbable we are". When you consider everything from getting ANY type
> of life started in the first place, right up until the point where sentient
> life develops, it really makes you think. I've even heard it said that
> without the moon, there is no chance that humans would have developed, since
> it has often protected us from asteroid impact. Every time organisms
> started evolving to a certain level, BANG!
It has also been hypothesized that without Jupiter there would probably
be no life on Earth because Jupiter has cleared the solar system from most
of the dangerous asteroids. OTOH, another study contradicts this and claims
it has no effect (and may, in fact, be the opposite, that Jupiter might
actually cause us *more* danger than less, but we have just been lucky
so far).
Even if the Moon has helped the formation of life in some way, it doesn't
mean that life would be impossible without it. Even if the danger of
total destruction is greater, life can still get lucky. If not on this
planet, on one of the trillions and trillions of other planets out there
(this is the anthropic principle).
> Anyway, yes. There are so many things to consider that it really makes you
> wonder if we actually are alone in the universe.
My take: If there is life in the Universe (which happens to be the case),
some of that life must have been the first one to form. Well, we might just
be that first, don't you think?
The anthropic principle can also be applied in this case: The first
intelligent life to form will inevitably wonder why they don't detect
any other intelligent life. The answer is pretty obvious: Because they
are the first, and there is no other intelligent life yet.
--
- Warp
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Warp wrote:
> My take: If there is life in the Universe (which happens to be the case),
> some of that life must have been the first one to form. Well, we might just
> be that first, don't you think?
I always enjoyed thinking about such things. What if we really *are* in the
middle of the universe, and it's not that space is expanding, but only that
everything really is rushing away from us because it all started right near
here? :-)
--
Darren New, San Diego CA, USA (PST)
"How did he die?" "He got shot in the hand."
"That was fatal?"
"He was holding a live grenade at the time."
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Le 25/01/2011 21:11, Warp nous fit lire :
> The anthropic principle can also be applied in this case: The first
> intelligent life to form will inevitably wonder why they don't detect
> any other intelligent life. The answer is pretty obvious: Because they
> are the first, and there is no other intelligent life yet.
>
There is no intelligent life yet.
http://xkcd.com/638/
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On 25/01/2011 08:11 PM, Warp wrote:
> My take: If there is life in the Universe (which happens to be the case),
> some of that life must have been the first one to form. Well, we might just
> be that first, don't you think?
My understanding of general relativity is limited, but I was under the
impression that "first" is not a meaningful concept at relativistic
velocities.
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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Darren New <dne### [at] sanrrcom> wrote:
> I always enjoyed thinking about such things. What if we really *are* in the
> middle of the universe, and it's not that space is expanding, but only that
> everything really is rushing away from us because it all started right near
> here? :-)
What's the difference?
--
- Warp
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On 1/25/2011 2:06 PM, Warp wrote:
> Darren New<dne### [at] sanrrcom> wrote:
>> I always enjoyed thinking about such things. What if we really *are* in the
>> middle of the universe, and it's not that space is expanding, but only that
>> everything really is rushing away from us because it all started right near
>> here? :-)
>
> What's the difference?
>
In terms of the universe in general, none. The "edges" are one big blur
of stuff moving away too fast to see anything but the blur from it, and
without reference to the edges, you can't define the "center". In
relation to everything else... umm.. just pick something to be the
center, and go with it?
--
void main () {
if version = "Vista" {
call slow_by_half();
call DRM_everything();
}
call functional_code();
}
else
call crash_windows();
}
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