On 5 May 2014 at 0:24, Richard Aiken wrote:

> On Sun, May 4, 2014 at 10:31 AM, Bruce Johnson
> <xxxxxx@pharmacy.arizona.edu> wrote:
>
> <http://rationalwiki.org/wiki/Irreducible_complexity>
>
> Evolution, at it's heart, is essentially a bodger. Complex mechanisms
> are made of smaller bits that may have been something else entirely
> to start.
> I went to that link and read the article. This bit - arguing that
> component bits of something like the Krebs Cycle might have been part
> of something else originally - snagged my attention:
> " each mutation can arise independently, spread through the
> population by natural selection, and combine through sexual
> reproduction (or gene transfer in simpler organisms)."
>
> Doesn't this actually break natural selection, though? Organisms with
> currently-useless bits are less efficient than ones without them, so
> natural selection would not operate in favor of keeping an (only
> useful in the future after it meets its other half) mutation in the
> gene pool. It could still happen - humans have that pesky appendix,
> after all - but it wouldn't be *selected.* So we're back to random
> chemical junk (which doesn't do anything currently beneficial within
> an organism) randomly combining into something useful.

Nol, they can be selection neutral. More to the point, they can be
good for *something else* other than what they are currently used
for.

> It seems to me that what would need to happen - for this argument
> against irreducible complexity to be valid - is for the components of
> each future beneficial chemical process to remain part of a
> functional currently-beneficial process (in order to be spread
> through the gene pool). The correct currently-beneficial processes
> would then need to simultaneously - inthesame reproductive event -
> break down into individually-useless fragments, which fragments would
> then need to immediately re-combine into a new beneficial process.

Nope. "Parts" can be used in *multiple* processes in an organism. And
persist for a long time after "something better" comes along.

The article actually talks about that sort of thing a bit and you can
easily fill in the rest with a bit of thought.

--
Leonard Erickson (aka shadow)
shadow at shadowgard dot com