Re: Southwind post#310
Organisms tend to resemble thier parent(s), however there are slight differences. If these differences increase the average number of offspring that themselves reproduce, they will spread. If they decrease the average numner they will decline. Those organisms with traits that result in a more than one reproducing offspring per parent will be the ones that will in the liong term evolve. The organisms are sucessful at replication because of their traits, which their descendants will tend to have.
The population seed for the next generation is made up of those organisms with parents that have already demonstrated the suitability of their traits by reproducing.
Over time the slight differences that are beneficial will tend to get acquired whilst those that are not will tend to get eliminated.
The process is
gradual, due to the fact that organisms tend to imperfectly resemble their parent(s). The
change is present because those random changes that improve the average number of children per parent above one, will remain in the population, and further changes can act to further "optimise" the organism's descendents.
If the main anti-evolution proponents accept gradual change, then trying to fight a attle on this is pointless.
Post#292
So, if, as an 'engineer', I took a machine, in an early stage of its development (evolution!) and said: "OK, I'm gonna make a random change to one of its components, be that a change in length, width, weight, material composition, whatever, and see what effect that has, and if the effect is good or indifferent, as judged by its ability to serve a useful function, then I'll retain that change, but if the effect is bad then I'll reject that change and try another random change.", how does that differ from natural evolution?
That is an evolutionary algorithm, but not evolution as the selection criteria are predetermined as an intelligence is determining the benefit.
The same with selective breeding or more explicitly "artificial selection".
Artificial selection is not natural selection. There is a reason why they have different names.
Agreed, but that's because we're dealing with different technologies. If all a 'competent designer' had to play with were the organic materials and systems that define the mamalian eye, plus all the related and interacting body parts and functions, what do you think he might come up with, a video camcorder?! Now that IS a completely flawed analogy!
The octopus and squid got it right.
You're missing the point, and actually helping argue my case here. The prototype to which you refer (which was, undoubtedly, based largely upon previous aircraft, as we've previously established) was only one of many (very many!)that could have been produced. Each alternative prototype could be considered a mutation of the common 'ancestor' (or parts thereof). The particular prototype that you refer to failed and became 'extinct'. For every prototype that could have been produced and failed, a prototype could have been produced and succeeded, and gone on to 'breed' (at least one of those prototypes would, by chance, happen to have had extra plywood strengthening at the point of the break!). As I've previously pointed out, it is simply more time and cost effective to make prototypes that fail and are addressed at the point of failure than to make every conceivable prototype and retain those that just happen to work ( a la natural selection).
jimbob said:
The point was that this failure provided the information to correct the fault. With an evolutionary approach the only information you would have is that some failed and some didn't.
Evolved systems often look completely different from designed systems. No halfway competent designer would design the mamalian eye as it has evolved. "Lets require a blind spot, and lets obscure the light-sensitive cells with blood vessels"
I can't believe you've posted the quote above AND THEN written what you have! You've CLEARLY missed my point YET AGAIN, the very point made in the quote!
Yes, the failure to which you refer did provide the information to correct the fault, BUT THAT WASN'T THE ONLY WAY THAT IT COULD HAVE BEEN 'CORRECTED'! ALTERNATIVE PROTOTYPES WOULD HAVE ENSURED THAT THE FAULT NEVER EVEN OCCURRED (at least not in the prototypes that would have gone on to survive)!!!
This is whre I disagree with you.
Assume that one starts with two copies of the same design.
One performes an evolutionary algorithm, (not evolution) and imperfectly copies the prototype many times, removing those which fail.
Another performs classcal engineering.
Both initial prototypes fail. The classical approach would be to fix just the problem, the evolutionary algorithm is to randomly alter the design parameters and select the prototype with the best fitness score for the next iteration.
Eventually both approaches produce successful designs.
The product of the classical engineering approach will look far more similar to the initial design than the evolutionary algorithm because the only changes were to the parts causing the problem.
Yes it is possible that a succession of random changes would have produced a similar product, but (unlike discussions of ID, the odds really are agianst this). There is a strong probability that the evolutionary approach would produce a better result (in a lot more iterations). But it would not be so similar to the "parent". One would expect to see a multitude of differences between "generations", some beneficial, and others neutral. With a classical approach the alterations would be with the express intent to solve
specific problems.
With an evolutionary approach the only information you would have is that some failed and some didn't.
And this is
EXACTLY THE SAME as building multiple prototypes then observing which fail and which don't; exactly as I've described in the quote that
YOU'VE POSTED above!!!
PLEASE RE-READ IT CAREFULLY.
Evolved systems often look completely different from designed systems.
I don't think you really mean 'systems', rather 'organisms/machines', or similar, i.e. the outputs. The evolutionary system and mechanical design process (some, at least) look very different, '
LOOK' being the operative word, as right from the OP I've been referring to the
CASUAL OBSERVER. I'm sure, from what I've read here, that the biology and mechanics that occur at the micro level 'behind the scenes' are completely different,
BUT THE ITERATIVE PROCESS AND RESULTANT COMPLEXITY CAN BE VERY COMPARABLE.
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The complexity can obviously be comparable, both processes are iterative, but the way the processes work would introduce differences between subsequent "generations" that would be indicitive of which approach was being used.
A single "generation" might be sufficient to indicate this. Many generations would make it far easier to spot.