Replies

Some combinations of existing genes and mutations will produce more offspring than others; hence, these combinations and mutations will be present in a higher percentage in the next generation; of these, some combinations, ... Repeat.

Yeah, but if it's all random, how would a complex organ like an eye or an ear "evolve?" Or lungs? Or...self-consciousness?

Your post reminded me of this fine reply made by r9etb. You might like to read it.

. . . discussion of "organic units" touches upon a seldom-discussed facet of this whole "ID vs. Evolution" debate (even though it does inform Behe's ideas of irreducible complexity). Namely, there is a "system-level" aspect to the problem that is hard to address by appealing to individual mutations that may or may not be advantageous. <--snip-->

Me: Some combinations of existing genes and mutations will produce more offspring than others; hence, these combinations and mutations will be present in a higher percentage in the next generation; of these, some combinations, ... Repeat.

You: Yeah, but if it's all random, how would a complex organ like an eye or an ear "evolve?" Or lungs? Or...self-consciousness?

What's random about some combinations of genes being better able to have offspring in some environment? Let's say the climate's getting colder. Some animals will, at random, have a combination of metabolism and fur that works better in a cooler environment than in a hot one; they're more likely to pass their genes down to the next generation. Which particular individuals have the better combination is random, but which ones survive and reproduce isn't.

The classical argument for eye evolution is from Darwin himself. He observed that for living organisms there is practically a continuum of eyes, from simple pigment spots to vertebrate eyes. It is easy to see how simple mutations can convert a simple pigment spot to a deeper and deeper cup, then, a step at a time, into our own eyes. It is also obvious that any improvement in this organ will provide a survival advantage - "in the land of the blind the one-eyed man is king"

Here's a good place to start your literature search.