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."
You can't read the article on the web unless you are a SciAm subscriber, and if you are, you would have seen it in the print version.
No. I keep dredging it up for an example because I had a friend when I was young who was slowly eaten up by polio. One wierd disease.
They do tend to be obsessive-compulsive...
If we get something approaching artificial intelligence, they will.
Incredible!
Forest green.
Liar yourself, as you said "You can't read the article on the web unless you are a SciAm subscriber". I am not a subscriber. I stopped reading it regularly when it became a thin propaganda tool and not an unbiased source of scientific information.
I tracked down a source for the full article and posted the link in 1014. It still has no evidence for the claim made concerning the cubic function generator.
I'd like to see your proof of this.
Are green cats dead or alive?
Which portions? Are you a literalist respecting all other portions of the bible which you are not a literalist about?
No "WE" didn't. The claim was made that numerous patents for evolved inventions were granted. I pointed out that in the article one of the participants claimed that "If (as we expect) the patent is granted, we believe that it will be the first one granted for an invention created by genetic programming.". Clearly, that prohibits even one patent existing for a invention created by genetic programming.
Are you not aware that pending patent applications cannot be searched, only granted patents?
Gee, didn't you get the impression that I am capable of looking for things and can read and do read instructions?
This home page "http://www.uspto.gov/patft/index.html" has a boxed area containing a green area and a yellow area. The green area has this title ---> Issued Patents (full-text since 1976, full-page images since 1790)
And the yellow area has this title ---> Patent Applications (published since 15 March 2001)
I guess that means that patent applications can be searched.
Is this is serious question?
Ahh. You would probably get a kick out of it. He predicts that Moore's law will allow us to have computers which can perfectly model the human brain neuron by neuron within fifty years. Kurtzweil claims, people will be able to scan their brains and establish in-silico versions of themselves...essentially immortality! I was wondering what someone familiar with AI would have to say about all this.
Interestingly, he speculates, that sole reason for humans on the planet is to create machines faster/smarter etc.
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