Posted: Jul 01, 2010 4:50 am
by Rumraket
CharlieM wrote: Matzke has proposed this model based on his views on how evolution proceeds and this assumes that the type III secretory system is ancestral to the flagellum.

Matzke doesn't have a unique "view" on how evolution works. Matzke is working from the generally accepted parameters of evolutionary theory. It has a number of testable predictions, these predictions are observationally confirmed. Therefore the evolutionary models has empirical support.

CharlieM wrote:I could propose a model based on my understanding of how evolution proceeds in which various bacteria make use of an archetypal plan which contains the "instructions" for making flagellar motility and secretion systems. This plan is expressed variously by different bacteria and sometimes in the same bacterium depending on physical factors. With my plan it doesn't matter which system (type III or Flagellum) came first.

Both our models can fit the observed data. Its our beliefs that determine the model, the data is the same in both cases.

Ahh, another version of the "I can design a machine in such a way that it looks like it evolved"-argument. Well good for you but I'm afraid this doesn't highlight a weakness in evolutionary theory, only the lengths to which you would go in order to cast doubt on evolutionary theory. I can also doctor up the evidence on a crime scene for a murder trial, are we now supposed reject the rule of law?
Essentially, this is an admittance that it looks like the flagellum evolved. Which brings us to the conclusion that IF it was designed, the designer is deliberately decieving us. Nothing we can do in that situtation though.

CharlieM wrote:I was talking about natural selection on its own. I know things are different when mutations are taken into account. My point was that natural selection cannot create novelty it only removes or lets through what is already there.

Yes and as I was saying natural selection acts on stuff with gain or cost. Some things are neutral, some are both gains and costly. If they have higher gain than cost, they will still be positively selected. I think you get the picture.