On Sun, May 04, 2014 at 02:02:21AM -0400, Richard Aiken wrote:
> I remember reading someone's argument against undirected evolution
> which used the Krebs Cycle (an essential and extremely complex
> chemical process within photosynthesis) as an example of unavoidable
> interdependent equilibrium. A partial Krebs Cycle does nothing
> beneficial for an organism.

Actually it does, in that fragments of the cycle can serve other
purposes than aerobic metabolism.  There are also some less complex
(though less efficient) cycles that have multiple steps in common with
the Krebs cycle.  They're really quite a versatile set of reactions,
even apart from the primary purpose that modern aerobic organisms use
them.

I'm quite surprised that any molecular biologist would hold such a
view -- unless they were rationalizing some excuses to support a
preconceived notion.

- Tim