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."
To accuse somone of moral relativism is nothing more than to assert that you differ about the role of motive.
Say what? By your reasoning, the state can abridge every one of your unalienable rights if their "motives" are "correct". Maybe you should rethink part B of your answer, eh?
Meaning what? That slavery is relative to geography and time. Either enslavement is right or it's wrong no matter who disagrees.
A profession of faith. :-)
Don't pretend the naturalistic origin of the universe has nothing to do with evolution. It is a serious problem for evolutionists and ignoring it won't make it go away.
Paul who? The Apostle Paul? He didn't write Hebrews! Your inference is not reasonable since it wasn't inferred. "Evidence of things not seen" is not the same as "evidence of things not detected." "Elegchos" is literally "proof" and "ou blepomenon" means "things not being seen with the eyes" like wind and gravity.
There are quite credible alternative explanations for the Universe,
Credible to whom? To those who demand an alternative to God? Isn't that like the Dems offering a feeble and token tax cut as an alternative to Bush's tax cut? It certainly is an alternative, but it is credible only to the Dem faithful.
After all, *why* did God create the universe?
Every catechism has that question and answer in it. A more interesting question might be *why* did the universe create itself?
Tell that to Dataman. He says it's the only obvious explanation.
I'm not an atheist. I'm quite willing to admit an omnipotent, supernatural God. I just wonder how that God would make His motives known to creatures so far inferior in power and intellect. In other words, if you have an ant-farm, how do you explain to the ants why you created an ant-farm for them?
We really don't have any hope of understanding this right now is an acceptable answer. Telling us all how this vastly superior creature *must* have done it is hubris beyond the scope of the Greeks.
I don't think a lawyer wrote this---
The cathode of the diode D2 is connected to the anode of the diode D3. The cathode of the diode D3 is connected to circuit ground 315.
The collector of the transistor Q1 is connected to the positive voltage rail 310. The emitter of the transistor Q1 is connected to the base of the transistor Q2 and to a first terminal of the current source I.sub.1. The second terminal of the current source I.sub.1, is connected to circuit ground 315.
The collector of the transistor Q2 is connected to the positive voltage rail 310. The emitter of the transistor Q2 is connected to the base of the transistor Q3 and to a first terminal of the current source 12. The second terminal of the current source I.sub.2 is connected to circuit ground 315. The emitter of the transistor Q3 is connected to circuit ground 315 and the collector of the transistor Q3 supplies the output current I.sub.out.
In operation, the circuit 300 generates the cubic part of the transfer function so that: ##EQU2##
However, the circuit 300 only functions at voltages at or above approximately 3 volts. This is because the topography of the circuit requires a voltage of 3*(V.sub.be,+V.sub.ce(sat)), and the value of V.sub.be may be as high as 0.8-0.9 volts, while the value of V.sub.ce(sat) is 0.3 volts. The 3 volt limit makes the circuit unusable for many applications. For example, many low-voltage power amplifiers have a maximum voltage requirement of 2.7 volts.
I think the original assumption should be a blank hard-drive. Where do you think the simulation will go from there?
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