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Artificial Life Experiments Show How Complex Functions Can Evolve
NSF ^ | May 8, 2003 | Staff

Posted on 05/08/2003 10:11:06 AM PDT by Nebullis

Artificial Life Experiments Show How Complex Functions Can Evolve

Arlington, Va.—If the evolution of complex organisms were a road trip, then the simple country drives are what get you there. And sometimes even potholes along the way are important.

An interdisciplinary team of scientists at Michigan State University and the California Institute of Technology, with the help of powerful computers, has used a kind of artificial life, or ALife, to create a road map detailing the evolution of complex organisms, an old problem in biology.

In an article in the May 8 issue of the international journal Nature, Richard Lenski, Charles Ofria, Robert Pennock, and Christoph Adami report that the path to complex organisms is paved with a long series of simple functions, each unremarkable if viewed in isolation. "This project addresses a fundamental criticism of the theory of evolution, how complex functions arise from mutation and natural selection," said Sam Scheiner, program director in the division of environmental biology at the National Science Foundation (NSF), which funded the research through its Biocomplexity in the Environment initiative. "These simulations will help direct research on living systems and will provide understanding of the origins of biocomplexity."

Some mutations that cause damage in the short term ultimately become a positive force in the genetic pedigree of a complex organism. "The little things, they definitely count," said Lenski of Michigan State, the paper's lead author. "Our work allowed us to see how the most complex functions are built up from simpler and simpler functions. We also saw that some mutations looked like bad events when they happened, but turned out to be really important for the evolution of the population over a long period of time."

In the key phrase, "a long period of time," lies the magic of ALife. Lenski teamed up with Adami, a scientist at Caltech's Jet Propulsion Laboratory and Ofria, a Michigan State computer scientist, to further explore ALife.

Pennock, a Michigan State philosopher, joined the team to study an artificial world inside a computer, a world in which computer programs take the place of living organisms. These computer programs go forth and multiply, they mutate and they adapt by natural selection.

The program, called Avida, is an artificial petri dish in which organisms not only reproduce, but also perform mathematical calculations to obtain rewards. Their reward is more computer time that they can use for making copies of themselves. Avida randomly adds mutations to the copies, thus spurring natural selection and evolution. The research team watched how these "bugs" adapted and evolved in different environments inside their artificial world.

Avida is the biologist's race car - a really souped up one. To watch the evolution of most living organisms would require thousands of years – without blinking. The digital bugs evolve at lightening speed, and they leave tracks for scientists to study.

"The cool thing is that we can trace the line of descent," Lenski said. "Out of a big population of organisms you can work back to see the pivotal mutations that really mattered during the evolutionary history of the population. The human mind can't sort through so much data, but we developed a tool to find these pivotal events."

There are no missing links with this technology.

Evolutionary theory sometimes struggles to explain the most complex features of organisms. Lenski uses the human eye as an example. It's obviously used for seeing, and it has all sorts of parts - like a lens that can be focused at different distances - that make it well suited for that use. But how did something so complicated as the eye come to be?

Since Charles Darwin, biologists have concluded that such features must have arisen through lots of intermediates and, moreover, that these intermediate structures may once have served different functions from what we see today. The crystalline proteins that make up the lens of the eye, for example, are related to those that serve enzymatic functions unrelated to vision. So, the theory goes, evolution borrowed an existing protein and used it for a new function.

"Over time," Lenski said, "an old structure could be tweaked here and there to improve it for its new function, and that's a lot easier than inventing something entirely new."

That's where ALife sheds light.

"Darwinian evolution is a process that doesn't specify exactly how the evolving information is coded," says Adami, who leads the Digital Life Laboratory at Caltech. "It affects DNA and computer code in much the same way, which allows us to study evolution in this electronic medium."

Many computer scientists and engineers are now using processes based on principles of genetics and evolution to solve complex problems, design working robots, and more. Ofria says that "we can then apply these concepts when trying to decide how best to solve computational problems."

"Evolutionary design," says Pennock, "can often solve problems better than we can using our own intelligence."


TOPICS: Culture/Society; Miscellaneous; News/Current Events
KEYWORDS: ai; crevolist
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To: gore3000
.I'm not an athiest.

Please donh, you do not believe in God,

I don't believe in YOUR God, that doesn't make me an athiest. Athiests have an assured positive opinion about the non-existence of God--you will search in vain for any statement of mine that categorically denies the existence of God--yours, mine, or anybody elses. You could get away with calling me an agnostic, although that is pretty sloppy attention to detail, but if you care a whipstitch about the proper use of language, I don't remotely qualify as an athiest.

1,001 posted on 05/09/2003 9:19:18 PM PDT by donh
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To: CobaltBlue
Be honest now, nobody on this thread has told you that he/she hates God.

Be honest yourself, plenty have said that the idea of God is ludicrous. Your semantic games do not change the fact that the evolutionists here are thoroughly opposed to Christianity and to any explanation of anything that involves God the Creator.

1,002 posted on 05/09/2003 9:20:54 PM PDT by gore3000
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To: donh
I don't believe in YOUR God, that doesn't make me an athiest.

Okay, so what God do you believe in? You are hiding behind a semantic paper curtain.

1,003 posted on 05/09/2003 9:22:57 PM PDT by gore3000
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To: AndrewC
There is no such evidence for the 17 transistor kludge.

In other words... it's a you-versus-them issue.

If you truly are curious... come back when Scientific American's website is up and get their referred works from that article and run these papers through an university library. If you don't have access to an university, you can FreepMail me with the citations you want to look up and I'll retrieve them by interlibrary loan.

When in doubt, go to the original.
1,004 posted on 05/09/2003 9:26:56 PM PDT by Nataku X (Never give Bush any power you wouldn't want to give to Hillary.)
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To: Old Professer
An interesting concept that, another 50 years to witness this unfolding of what?

The end of algorithmic, functional programming, for one thing.

Man, a reasoning, although not necessarily reasonable, creature shall abandon hope and paradise for more time to look forward to machines smarter than himself?

Reasoning is just a small part of the having-an-advanced-technical-culture game. In some ways, all machines are smarter than all humans. I can get a warranty from Goodyear for my tire to faithfully perform a mindless task for 5 years, day in and day out, without fail. Goodyear wouldn't dream of offering such a warrant on a person, would they?

In my humble opinion, we are rapidly approaching the point where it will be often impossible to debug our code, and our code, consequently, is going to have to learn to be responsible for discerning and fixing it's own bugs. Or, more likely, ignoring them with impugnity.

Just as well I'll be out of this picture--I was born&raised to smite bugs to restore code to it's pristine crystalline beauty, and this will be a foreign world to me.

1,005 posted on 05/09/2003 9:35:43 PM PDT by donh
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To: Aric2000
...or he just comes apart at the seams. ...

Or "He becomes unblued."

1,006 posted on 05/09/2003 9:38:19 PM PDT by Doctor Stochastic (Vegetabilisch = chaotisch is der Charakter der Modernen. - Friedrich Schlegel)
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To: donh
Interesting perspective, how about a milkshake?
1,007 posted on 05/09/2003 9:42:56 PM PDT by Old Professer
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To: donh
The end of algorithmic, functional programming, for one thing.

Probably right for mainline applications. There will always be some use for programmers, just as mathematicians still find things to do. I mean, we need to do something besides watch videos and go fishing. Or maybe it won't be so bad after all, come to think of it.

1,008 posted on 05/09/2003 9:42:59 PM PDT by RightWhale (Theorems link concepts; proofs establish links)
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To: donh
The "Game of Life" (Conway's) is interesting because some randomly generated configurations can become universal Turing machines. The same for some of Wolfram's cellular automata. A randomly chosen cellular automaton has 1 chance in 256 of being able to simulate a universal Turing machine.
1,009 posted on 05/09/2003 9:45:36 PM PDT by Doctor Stochastic (Vegetabilisch = chaotisch is der Charakter der Modernen. - Friedrich Schlegel)
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To: Dad was my hero
Some imprudently and indiscreetly hold that evolution, which has not been fully proved even in the domain of natural sciences, explains the origin of all this, and audaciously support the monistic and pantheistic opinion that the world is in continual evolution.

You will kindly note, from your own evidence here, the phrase "...evolution, which has not been FULLY proved even in the domain of natural sciences..."

The reason this document is couched this way is because the Church has, for quite some time now, accepted Darwin's theory of evolution, agreeing with Darwin that the theory of evolution does NOT address the evolution of all that is, and in particular, does not address the earliest origins of life. The mystical uber-extension of Darwinism this is railing against was equally opposed by Darwin.

And, by the way, there's no such thing as proof (as a source of certainty) in any in the natural sciences, as the church fathers who drafted this are well aware.

1,010 posted on 05/09/2003 9:47:52 PM PDT by donh
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To: Lurking Libertarian
How did hair dyes get into the discussion?
1,011 posted on 05/09/2003 9:51:08 PM PDT by Doctor Stochastic (Vegetabilisch = chaotisch is der Charakter der Modernen. - Friedrich Schlegel)
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To: gore3000
It takes a lot of gibberish to hide the fact that the author is hiding a big problem in the experiment - the fitness cost of non-performing functions.

Piffle. What is the "fitness cost" of a piece of code that never gets performed, or a segment of memory that never gets used? Computer simulations are not real biological worlds, where the cost of failure is loss of resource to the genome. In simulations, the cost of failure is a few immesurably small smidgens of juice from the wall socket. It isn't writ in stone that I need to punish failure with certain death, as long as I provide some differential advantage to the sucesses. It's a truism of entomology (been demonstrated in sealed mason jars thousands of times) that when two nearly identical species occupy nearly the same contained biological nitche, one or the other will eventually prevail entirely, no matter how tiny its differential advantage.

1,012 posted on 05/09/2003 9:59:30 PM PDT by donh
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To: Old Professer
Interesting perspective, how about a milkshake?

I don't believe turing machines will replace milkshakes in the near term future.

1,013 posted on 05/09/2003 10:03:31 PM PDT by donh
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To: Nakatu X
If you truly are curious... come back when Scientific American's website is up and get their referred works from that article and run these papers through an university library.

I'm actually curious enough to read the stuff. That is why I know they have no evidence. I read the thing here---Evolving Inventions

You will note they have no references for the experiments. What references are there give him a little spending money (except for the Turing ref)


Computing Machinery and Intelligence. Alan M. Turing in Mind, Vol. 59, No. 236, pages 433–460;
October 1950. Available at www.abelard.org/turpap/turpap.htm by permission of Oxford
University Press.
Genetic Programming: On the Programming of Computers by Means of Natural Selection.
John R. Koza. MIT Press, 1992.
Genetic Programming: The Movie. John R. Koza and James P. Rice. MIT Press, 1992.
Genetic Programming III: Darwinian Invention and Problem Solving. John R. Koza, Forrest H
Bennett III, David Andre and Martin A. Keane. Morgan Kaufmann, 1999.
Genetic Programming III: Videotape: Human-Competitive Machine Intelligence. John R. Koza,
Forrest H Bennett III, David Andre, Martin A. Keane and Scott Brave. Morgan Kaufmann, 1999.
Genetic Programming IV: Routine Human-Competitive Machine Intelligence. John R. Koza,
Martin A. Keane, Matthew J. Streeter, William Mydlowec, Jessen Yu and Guido Lanza.
Kluwer Academic Publishers (in press).

1,014 posted on 05/09/2003 10:04:53 PM PDT by AndrewC
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To: gore3000
Okay, so what God do you believe in? You are hiding behind a semantic paper curtain.

As usual, you are full of everything but the minutest hint of a memory. I believe God exists, and that he is evil, and does not deserve to be worshiped, based abundantly on the evidence available. I'll cite one example to try to trigger your execrable memory of our previous contacts: God created polio viruses of of exactly the same DNA/RNA machinery as my child's nervous system, so that polio viruses would find my child's nervous system a delicious meal. For that act alone, God deserves to be hunted down and slaughtered, before he gets it into his head to ram the moon into the earth so he can enjoy watching us squirm&burn.

1,015 posted on 05/09/2003 10:11:13 PM PDT by donh
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To: RightWhale
I mean, we need to do something besides watch videos and go fishing. Or maybe it won't be so bad after all, come to think of it.

Being a natural cynic, I paint a grimmer picture than really needs be. It will be a long time before computers are capable of, say, love, loyalty, adventurousness, curiosity, creativity, joy, comraderie, yearning, or duty. What we are that is presently unduplicable by machinery is creatures of the flesh, with all the advantages and horrors that brings to the table. It will still have more net cash value in the market than all the computational capacity you could ever muster for some time to come. And when that is no longer so, I will no longer care.

1,016 posted on 05/09/2003 10:24:14 PM PDT by donh
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To: donh
Reasoning is just a small part of the having-an-advanced-technical-culture game.

Matter cannot reason and not even the most ardent materialists argue that living things can will themselves into a new species so this argument is absolute nonsense.

1,017 posted on 05/09/2003 10:40:29 PM PDT by gore3000
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To: donh
What is the "fitness cost" of a piece of code that never gets performed

Exactly what I mean, an electronic model does not have such a fitness cost. However, in real life there is a fitness cost of non-useful organs, DNA, etc. It takes energy, food, etc. to keep such useless things alive so there is definitely a fitness cost. This is just one of the examples why this model is false. In fact, you are agreein with me:

when two nearly identical species occupy nearly the same contained biological nitche, one or the other will eventually prevail entirely, no matter how tiny its differential advantage.

Further, as I mentioned, the problem for evolution is to slowly, gradually, in small steps create a totally new organ, function, etc. with each single step making the organism more fit. This is the part of my argument you do not wish to discuss.

1,018 posted on 05/09/2003 10:50:46 PM PDT by gore3000
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To: donh
. I believe God exists, and that he is evil

Well, you have often stated that God did not create life and argue for life from non-life. So it seems that if you believe in God, it is a powerless one. Regardless, you are just trying to avoid the atheist label by playing games. Your attitude towards religion is completely the same as that of an atheist.

1,019 posted on 05/09/2003 10:58:41 PM PDT by gore3000
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To: gore3000
Exactly what I mean, an electronic model does not have such a fitness cost.

...and where is your proof that the beginnings of life had a fitness cost profile much different from the current electronic models?

1,020 posted on 05/09/2003 11:00:30 PM PDT by donh
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