Skip to comments.Artificial Life Experiments Show How Complex Functions Can Evolve
Posted on 05/08/2003 10:11:06 AM PDT by Nebullis
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."
Life begets life
Artificial life begets artificial life
Artificail Life begets artificail evolution
Here's Evolution in the making.
The evolutionary origin of complex features
RE Lenski, C Ofria, RT Pennock, C Adami
A long-standing challenge to evolutionary theory has been whether it can explain the origin of complex organismal features. We examined this issue using digital organismscomputer programs that self-replicate, mutate, compete and evolve. Populations of digital organisms often evolved the ability to perform complex logic functions requiring the coordinated execution of many genomic instructions. Complex functions evolved by building on simpler functions that had evolved earlier, provided that these were also selectively favoured. However, no particular intermediate stage was essential for evolving complex functions. The first genotypes able to perform complex functions differed from their non-performing parents by only one or two mutations, but differed from the ancestor by many mutations that were also crucial to the new functions. In some cases, mutations that were deleterious when they appeared served as stepping-stones in the evolution of complex features. These findings show how complex functions can originate by random mutation and natural selection.
Perhaps you know of a way to go back in time or speed up the reproduction of organisms?
You will eventually have to explain how a rigged program can design new and useful things that have not been foreseen by humans. It has already happened. A computer program using the technique described in this article has already designed a new, useful and patented electronic circuit.
This ain't a game anymore. And this is just the first few baby steps.
Amazing to what lengths athesits, oops evolutionists will go to to bolster their ridiculous theory. Something as sophisticated as the human body, didn't evolve out of nothing. Nothing comes from nothing. That is just OBVIOUS common sense for those who use their God given brains.
There is a sub-set of lunatic loons who appear to wish the end of American society as we know it. Like the Nazis and the communists in Weimar Germany, they have a great deal in common as ... potential destroyers --- of the social fabric.
I have engaged in several debates in the last few days, and I admire FreeRepublic as a forum for the free expression of ideas, but the overwhelming presence of this bunch of loons is very off-putting.
Lenin is supposed to have said that capitalists would sell him the rope by which they were to be hung. The anarcho-loons on this forum would not bother to sell the rope but provide it as a public service.
401 posted on 05/06/2003 5:54 PM PDT by moneyrunner (I have not flattered its rank breath, nor bowed to its idolatries a patient knee.)
Artificial life is not LIFE.
Evolution is a discredited religion.
Unfortunately, its adherents refuse to give up their faith.
I usually don't get involved in these threads, but that was my first thought. From a distant lens, they've done the following:
1. Created the world.
2. Created the rules.
3. Created the initial organisms.
4. Kickstarted execution.
5. Prompted evolution by introducing mutation external to the organisms.
6. Set the organisms loose on each other.
I played this game in the early '90's - it was called Unnatural Selection. Cool game.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.