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 continue an unbroken streak of responding only to the Peripheral parts of any argument.
I started a specific line of argument in #1446, and you ingnore the argument in favor of responding to the one-sentence lead in fluff.
Let me continue. Wolfram suggests that variations in mutation is highly constrained, which leads to the possibility that the calculations of astronomical odds against favorable mutations is bogus.
One could posit all kinds of religious and pseudo religious "causes" for this -- anything from God designing the physical constants to produce evolution, to "multiverse" scenerios in which every possible thing happens in infinite parallel universes.
In either scenerio, evolution happens, but Wolfram's hypothesis would explain why the probabilities favor evolution.
Look up the patent. And look up the logical fallacy.
If a spice output is good enough for the patent office, it is good enough for an argument on FR.
The evolved circuit is clearly more complicated but also contains redundant parts, such as the purple transistor, that contribute nothing to its functioning
So?
The mentioned part is clearly unterminated.
So what? So are stabalizing capacitors.
Solder 2 diodes back-to-back and see if you get a transistor.
This is a fundamental fact of circuit theory, taught to freshmen EE's the world over. That's exactly what you get when you "solder" two diodes together on the backplane of a piece of flat silicon.
And you continue to produce things that I did not write. I merely said they were provocative. I took no side in the actual statements.
I will expostulate further: When you are trying to make an argument that only humans can design, it is unpursuasive to offer as evidence that because humans designed a particular circuit, it is therefore the only candidate to have been designed. I'll go on at greater detail if you still cannot see why this is a post hoc, ergo propter hoc argument.
That is B.S. and you know it. It is taught as a concept, as I pointed out, and exactly the reason you put "solder" in quotes.
I put "solder" in quotes, because all you can do with a solder gun is destroy both diodes, as you no doubt know. It is taught as a concept, because it is a concept, as are all other things taught to beginning EE's in circuit theory classes.
This is an absurd argument, based on you being as willfully ignorant, and/or pointlessly didactic as you can manage. Find a beginning college level EE theory book and look for yourself. This is a piece of commonplace knowledge to EE's.
Gee, how about generating interest so that people will go look at the thread?
More B.S. I've soldered diodes back to back not to get a transistor but to get a bridge rectifier. The diodes were not destroyed. The bridge rectifier worked.
Left and right junctions, since you seem to have problems.
It should tell you it's behavior is only as accurate as the code that was compiled for it.
The fact that scientists were involved and setting up the scenario in which to conduct the experiment kind of puts a dent in the idea that this provides any support for 'unguided' evolution.
Where did you find that strawman? The discussion has been over the performance of a circuit patented by humans and a virtual one that came about as a result of a genetic algorithm.
Are they the same circuit?
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