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Digital Darwin
An anonymous reader writes "Using genetic algorithms to breed strings of computer code graphically, this week's Nature magazine describes results from Caltech and Michigan State. Their program is Avida. While they mainly mimic mutation, not genetic cross-over [or inheritance (thus wiping away much memory of initial conditions)], their simulations show how a short-term backward step in survival strategies can generate innovative advances. It is not unlike running a maze which necessarily involves testing alot of dead-ends, and thus shares the graphical look of Conway's classic Game of Life." Here's a National Geographic story about this as well, or see their press release.
LOL! Yes, I have sometimes wondered too how the heck you're supposed to prevent evolution on a hospitable planet hanging around a stable sun for billions of years.
I've done some GA work myself, and it is quite fascinating. E.g., too high a mutation rate and the system destabilizes, but too low a rate and it never (or very slowly) finds its optimum fitness. Throw in some genetic recombination (simulating sexual reproduction) and evolution to higher mean levels of fitness accelerates considerably as useful "genes" are conserved while others quickly disappear. It's very cool.
Modern creationists are in the same place that official Christiandom was in the time of Galileo, I think. If you're religious, nothing in modern biology (which largely is evolution) really denies a role for a deity in kickstarting the whole shebang. Setting up the system to run itself unattended, in fact, would have been the smart way to do it. Those who insist that God would create a system far inferior to this -- i.e., that requires endless hand-tweaking of every minute detail -- are really delivering Him a kind of insult, aren't they?
That makes the assumption that the anti-evolutionists are logical people.
:)
Very true. And, in the case of using genetic algorithms as a point of evidence in an argument, this assumption works against you. For many people computers are a black box. If you say, "I have a computer program that models mysterious process X" it's just replacing something mysterious with something incomprehensible.
And, before you do that, you have to assume that arguing is a productive activity in the first place. With many evolution deniers, it is not. But since they've wandered into my cave (the realm of logical, rational thought) I find it's my duty to eat them alive.
Its wonderful how these things can find odd and interesting solutions to problems in some cases and completely miss them in others.
One of the things that anyone learns who has tried this kind of method is that you can't hurry things to a result - that you often need to actively intervene to slow the evolutionary march, or even back it up (as in the article) or the system can easily get stuck exploring an area with a local optimimum extensively and miss a better one thats just a ways away.
Wonderfully fun stuff though and well worth investigating.
having just successfully completed an undergraduate project in which i have used genetic algorithms to achieve full adaptive image compression, i have learnt rather a lot about these curious beasts that is seldom mentioned in modern text. the use of genetic algorithms in a computer does in no way prove or disprove any evloution/anti-evolution argument. these algorithms do not magically evolve new creatures, or new solutions. they just search the solution space in a highly parallel manner, and they surprise people because they come up with solutions they did not consider. the solution is there waiting in solution space - but you can't find it because your brain is not capapble, you don't spend enough time on it... whatever. this is not new, its not intelligent, its not the creation of a new species. think of genetic algorithms as exploiting adaptive characteristics, simple as that, i.e. skin colour changing due to intensity of sunlight. of course... there are fields of research that involve using one class of genetic algorithms to derive the schemata (structure) of another class, but the research has come up with nothing to date.
-Drew
> The problem with "creation scientists" is the same problem with "evolutionary biologists" - each firmly believes in their position regardless of the weakness of the position or evidence to the contrary.
Could I trouble you to summarize the weakness of the position of evolutionary biologists and the contrary evidence? Presumably you have something beyond the same old tripe that has been refuted hundreds of times, or you wouldn't be saying that.
> Weak minds often have a hard time with the intelligent design arguments of creation. While we don't specifically deny evolution, we posit that there was a Creator who started the process, and has and does attend to his creation.
And that position is completely worthless as a way of understanding the universe, because it is compatible with any observation whatsoever.
> When one looks at the complexity of living things compared to that of inanimate objects, one can't help but be struck by the difference in complexity between what merely exists and those things that grow.
What measure of complexity are you using? I'd like to see your calculations showing the complexity of a squirrel and the complexity of the Nile delta.
But maybe before we get into that too deeply... What has complexity got to do with anything? Are you making an underlying claim that complexity can only come about as a result of intelligent design? Is the Nile delta the result of intelligent design? Are intelligent designers the result of intelligent design? (Where did the first intelligent designer come from?)
> Interestingly, while this study can show the merits of evolution, it does more to bolster the intelligent design theory than to destroy it. While the experiment was very interesting, we must remember that the digital organisms did have an intelligent designer - it's not like the programs sprang to life on their own!
Yes, and our simulations of continental drift are written by humans too. Are we to conclude that humans are pushing the continents around?
Study up on the concept of "non sequitur" when you have a little spare time.
Sheesh, evil *and* a jerk. -- Jade
Actually, this is incorrect. We started with simple digital organisms that were only capable of self-replication, and put them in an environment where they would get more CPU time (basically have their priority increased) if they performed certain mathematical computations, in this case bitwise boolean logic operations.
The organisms were only given a nand instruction to work with, and combinations of nands (linked together carefully with proper juggling of data) could be used to create any of the others. The equals operation (returns 1 where bits in the two sequences are the same, 0 where they differ) seems to require at least 19 instructions to perform. Its important to note that we did not reward partials solutions -- they either got the correct answer of they didn't.
For those interested, we also have a lot of our data related to the paper on our servers, http://myxo.css.msu.edu/papers/nature2003
Charles Ofria (Second author of the paper, and primary author of the software)
Micro-evolution doesn't produce new organs, make a reptile into a mammal or a fish into an amphibian. It doesn't mean that one day a reptile happen to be born with feathers so it was a bird. It's a small variation of what's already there. A change in color or size perhaps, or for example in turtles, the shape of a water turtles' feet are good for swimming while a land turtle's feet are good for walking.
I don't know why I bother because this is too easy. One of the facts that best support evolution is that there are no truely new organs. A brain is just overgrown ganglia. A scale is just a slightly modified form of skin. A feather and hair are just slightly modified scales. mammary glands are slightly modified sweat glands. In fact, the development of a truely different, truely new organ with no developmental ties to other previously existing organ systems would be clear evidence of design. So far, all the evidence is that if there is a designer, it works in ways that produce effects identical to evolution.
But what is amazing is that we have examples of such transformations forwards and backwards. We have arthropods that became land animals and later, insects that recolonized the water. We have amphibians that came to shore and reptiles, mammals and birds that went back to sea.
What Macro-evolution doesn't explain is species that can not advance without certain features, for example the giraffe. The giraffe has a very long neck, which is designed not only to reach tall trees, but also so that the giraffe can bend down and drink without his brain being gorged with blood and exploding. The giraffe has a very powerful heart for getting blood up its long neck, but when he bends down to drink blood is going very powerfully downhill with the added force of gravity. There is a spongy tissue around his brain that holds blood until he is done drinking, and, valvues in his blood vessles to keep more blood from coming into his head. If these things were not in place in the first species of giraffe at the dawn of time, the first species of giraffe would have died as a result of too much blood going to his head and there would simply be no more giraffes. Yet according to Macro-evolution it took a long amount of time for these complex things to develope. Were there ever short neck giraffes? Could be, but, would they be designed in such a way? These things are specifically designed for an animal with a very long neck. The powerful heart would kill a short neck giraffe. He'd die of high blood preasure, yet if the first long necked giraffe was born without a strong heart, it would have died from not having enough blood to its brain. So how did this complex animal come to be? There are many different species such as this that defy the theory of Macro-evolution, species with features that have to be in place in their full form for the species to simply exist and advance because without them they will simply die.
Of course, knowing a bit about what you are talking about would help quite a bit. The question to be thrown back is why can't these features develop in tandem through gradual incremental changes? Like most people who don't know a lick about evolution, you assume that one characteristic must have appeared first suddenly, leaving the other characteristics to radically catch up. This view is perhaps the fault of biology educators who over-emphasize the role of mutation in evolution and under-emphasize the role of diversity within populations. For a start while the problem of blood pressure regulation is more accute for giraffes, it is not unique to giraffes. Most of the features cited as essential to girafes are present to some degree in all mammals (the basic creationist problem of no original organs again). And in fact, we have short-necked giraffes (Okapi) in the present day that, amazingly enough show many of the adaptations cited as unique for giraffes.
But there are many other features of giraffes that make them bad candidates for design. For example, giraf