It seems you may have misunderstood the original argument. The iterative approach suggests increments so minute at each step that they wouldn't significantly impact an organism's survival at any given time. Also given the extremely slow process of evolution and the relatively short number of iterations it is infeasible to suggest such a solution. If a person would like to create an iPhone it's easy to tell them to start with a shitty scrap of metal and work from there. You can make that sort of argument as a solution for creating anything but it is clearly not feasible.
No, I understand the argument, it is just built on a false assumption about how the iterations work. That a change is small does not make its effects insignificant. A single codon change could profoundly alter the protein it encodes, and even a small change to a protein or its expression can have a massive effect on the organism. It's not the structures of an orgnaism that mutate, it's the instructions that generate those structures which mutate. Imagine for example a typo on a blueprint - where there was supposed to be a " instead there is a ' and suddenly instead of an 8 inch air vent, now you have an 8 foot door. There is no intermediate step where you have a useless 2 foot hole.
Evolution is not a slow process, it is an irregular process. The odds of a useful mutation popping up at any given time is low, but once it pops up it's there immediately. Yes, an evolutionary process could never make an iphone, but no is claiming that evolution produced the iphone. The complex systems evolution produces are things where all the changes are individually useful.
>so minute at each step that they wouldn't significantly impact an organism's survival at any given time.
That's the thing. Evolution isn't "survival of the fittest" or even "driven by more efficient anything", evolution is simply; if you die before you pass on your genes, you don't pass on your genes. Over long enough time scales, with large enough populations, with tight enough tolerances and strict enough niches, the system roughly approximates a directed iteration of more efficient parts.
Nothing about evolution prevents carrying forward explicitly negative mutations! Nothing about evolution prevents carrying completely unused functionality and features! Nothing about evolution guarantees monotonically increasing fitness!
The giraffe has a certain nerve that goes from it's brain, all the way down around it's aorta, back up it's neck, to it's tongue. It does this, because in the fish we all evolved from, such a detour was less than a centimeter longer than an "optimal" path, and as each next generation went in different directions, it's just not that big a deal. A few hundred extra calories in development, and rare instances of a negative injury outcome are just not going to get fixed, because evolution is almost never vigilant. Most higher level animals have mating behaviors that explicitly favor "wasted" energy, including the long neck of giraffes! Sexual selection has a stronger influence on most animals than evolutionary pressure.
> Also given the extremely slow process of evolution and the relatively short number of iterations it is infeasible to suggest such a solution
This is silly. The vast majority of the ground work for complex life was developed by single celled organisms that produced a new generation every half hour, there were billions of these little creatures experiencing basically any possible mutation all the time, and a water droplet with a billion short lived single cells is exactly the kind of tight tolerance, competitive atmosphere where evolution is most prominent!
Evolution is not iteration. Evolution is pruning bad branches in your breadth first tree based algorithm.
Why not? People think in such a short time and amount scale such that we cannot comprehend trillions of cells spending billions of years, iterating. Even a small change can be significant at those scales.
