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Posted: Mon Jul 10, 2006 12:22 pm
by Minimalist
From the excellent Scientific American article:
15 Answers to Creationist Nonsense.
8. Mathematically, it is inconceivable that anything as complex as a protein, let alone a living cell or a human, could spring up by chance.
Chance plays a part in evolution (for example, in the random mutations that can give rise to new traits), but evolution does not depend on chance to create organisms, proteins or other entities. Quite the opposite: natural selection, the principal known mechanism of evolution, harnesses nonrandom change by preserving "desirable" (adaptive) features and eliminating "undesirable" (nonadaptive) ones. As long as the forces of selection stay constant, natural selection can push evolution in one direction and produce sophisticated structures in surprisingly short times.
As an analogy, consider the 13-letter sequence "TOBEORNOTTOBE." Those hypothetical million monkeys, each pecking out one phrase a second, could take as long as 78,800 years to find it among the 2613 sequences of that length. But in the 1980s Richard Hardison of Glendale College wrote a computer program that generated phrases randomly while preserving the positions of individual letters that happened to be correctly placed (in effect, selecting for phrases more like Hamlet's). On average, the program re-created the phrase in just 336 iterations, less than 90 seconds. Even more amazing, it could reconstruct Shakespeare's entire play in just four and a half days.
http://www.sciam.com/article.cfm?articl ... =1&catID=2
Posted: Mon Jul 10, 2006 12:31 pm
by zagor
Minimalist wrote:From the excellent Scientific American article:
But in the 1980s Richard Hardison of Glendale College wrote a computer program that generated phrases randomly
you didn't get point
Posted: Mon Jul 10, 2006 12:38 pm
by Minimalist
Wouldn't be the first time.
Posted: Mon Jul 10, 2006 1:05 pm
by tj
Cool stuff Minimalist and right up my alley as well. Writing a genetic algorithm is a profound experience. The speed at which they are able to arrive at optimum solutions is simply amazing.
Of course, as in all things, they aren't perfect and there are pitfalls. I can't help but notice that genetic algorithms and computer simulations never convince religious people when their sacred cow is on the chopping block, yet they are always perfectly happy to get out of the projected path of a hurricane. Funny thing, that.
Posted: Mon Jul 10, 2006 1:08 pm
by Minimalist
yet they are always perfectly happy to get out of the projected path of a hurricane. Funny thing, that.
Well....some stay and pray. A lot of them drown. Every cloud has its silver lining.
Posted: Mon Jul 10, 2006 1:15 pm
by tj
This page has a great discussion of GAs as well as some Java applets that show them in action. It's a little thick I guess and the site is a little slow, but it's a great resource.
Posted: Mon Jul 10, 2006 1:25 pm
by Minimalist
Now that's a page for a night when one is having trouble sleeping!
Posted: Mon Jul 10, 2006 1:59 pm
by Frank Harrist
Minimalist wrote:Now that's a page for a night when one is having trouble sleeping!
HMMM? Oh sorry I dozed off. Anything with lots of math and numbers tends to make my eyes glaze over. I think with the other side of my brain.
Posted: Mon Jul 10, 2006 2:03 pm
by tj
Well, if nothing else, I've provided you guys with a cheap soporific!
Posted: Mon Jul 10, 2006 2:12 pm
by Beagle
tj, you seem to have quite an aptitude toward mathematics. I think that's neat. I have a son like that . I, on the other hand, am not math oriented.
It is the language of the universe though.
Posted: Tue Jul 11, 2006 1:22 pm
by Minimalist
Anything with lots of math and numbers tends to make my eyes glaze over
Does that include the Racing Sheet?
Posted: Tue Jul 11, 2006 1:27 pm
by Frank Harrist
Minimalist wrote:Anything with lots of math and numbers tends to make my eyes glaze over
Does that include the Racing Sheet?
I have never been to a horse or a dawg race, nor do I wish to go to one.
Posted: Tue Jul 11, 2006 1:37 pm
by Minimalist
Good for you.
Terribly cruel sports.
Posted: Tue Jul 18, 2006 10:12 am
by Minimalist
Again, to the inevitable annoyance of the ignorant, science marches on!
http://www.sciencedaily.com/releases/20 ... 154238.htm
Did these animals show survival patterns akin to extant living dinosaurs, the birds, as did their crocodilian cousins? Or, did they mirror that of more distantly related dinosaurs that lived in a similar environment? A pile of bones from the North American tyrannosaur Albertosaurus sarcophagus may hold the answer.
These animals "showed exceptional survivorship once they passed the hatchling stage," said Gregory Erickson of Florida State University, co-author of a paper reporting the results in this week's issue of the journal Science.
Posted: Wed Jul 19, 2006 5:12 pm
by Minimalist
More on Dinosaur Airlines....
http://www.livescience.com/animalworld/ ... _wing.html
The triangular delta-wing shape found on many modern fighter jets was used by a small reptile to glide between trees 225 million years ago, a new study suggests.
Sharovipteryx mirabilis is known from only a single fossil. It was about 8 inches long, weighed less than a tenth of a pound and lived during the late Triassic, a time when the first dinosaurs were still evolving. Scientists knew that S. mirabilis had a membrane stretched across its hind legs, which allowed it to glide, but the exact shape of this membrane and the way it was attached to the animal's body has been debated.