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."
Clarify please. You keep conflating issues.
Even the IT folks think genetic programming is a toy.
I suspect that when an array of old discarded Pentium 350s, properly programmed, can design patentable electronic circuits, the world is about to change. There are zillions of problems for which the desired performance perameters can be specified, but for which solutions by conventional methods are just too time consuming and expensive. Designing heating and cooling systems for large buildings, likewise elevator systems, electrical and plumbing systems. All of these systems involve "best fit" solutions, and human engineers rely on formulas and rules of thumb. I suspect that genetic programming will discover profoundly more efficient solutions, and do so with cheap, off the shelf computer hardware.
You seriously think we weren't trying to produce a better circuit?
Transistors in an IC are unbelievably cheap. Better performance is THE foundation of a designer's career.
Even a small increase in accuracy translates to larger market share, and can mean the difference between a company's survival or demise...
Why don't you read the patent and post 649 and learn something?
A transistor has a footprint measured in microns. One could easily fit 1,000 across the width of a single human hair. A 17 transistor circuit will fit ANYONE'S definition of compact.
I provided evidence. Let us see you provide something more than opinion.
And so does 9.
Yes. I've used transmutation doped silicon for precision photosensors.
The transmuted phosphorus is evenly distributed, chemical doping segregates into areas of varying concentration...
Yes. Silicon--->Phosphorus
Are you seriously suggesting that adding a dozen transistors will affect the physical size of an IC?
Not true. Ask any IP (Intelectual Property) lawyer. The working model requirement was dropped in the late 1800's
You have AC so rattled he forgot to post in blue.
I know single parens suffice. I know there is no space between the last word and the punctuation.
Don't you wish. Blue means I quoted someone. I didn't in that message. You might notice things like that. I also read the patent and the author was aiming for compactness.
I suggested that the person to whom I was responding read the patent. You might also try that suggestion.
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