dkomo  wrote or quoted:
> P wrote:
> > "dkomo"  wrote in message
> > news:cf840o$14kh$1{at}darwin.ediacara.org...
> >>Michael Ragland wrote:
> >>>Olivier d'ANHOFFRE wrote:
> >>>dkomo  wrote or quoted: >

> >>>I have seen genetic programs generate very high levels of
algorithmic
> >>>complexity using little more than selection, mutation and crossover.
> >>>There's no reason to think biological evolution can't do the same.
> >>>
> >>>Ragland:
> >>>Under what conditions biological evolution couldn't do the same?
> >>
> >>Not exactly sure what you're asking here.  Please provide more detail.
> >>However, I'll take a guess for right now.  Biological evolution often
> >>doesn't increase the complexity of an organism if that organism is so
> >>well adapted to its environment that *any* phenotypical change would
> >>decrease its fitness.
> >>
> >>In other cases biological evolution might reduce the complexity if a
> >>change in environment demands it.  The organism might actually increase
> >>its fitness by becoming simpler.  Parasites come to mind.
> > 
> > Do you have some concrete examples in mind?
> 
> Other than the case of parasites, I can't supply other examples without 
> going to some effort to look them up, primarily because I'm not a 
> biologist.

Parasites are a perfectly acceptable example.  Gut parasites lose
their limbs and wind up with just a mouth and a digestive system.

Orgainsms that go irreversibly blind from living in blackness underground 
or undersea are another example.

> In past discussions about whether evolution steadily 
> increases the complexity of life, I've been beaten about the head and 
> shoulders with examples from biologists illustrating (as far as they 
> were concerned) that evolution is just as likely to decrease an 
> organism's complexity as it is to increase it.  According to them life 
> spends as much time backing and filling as it does moving "forward." 
> Evolution is viewed as aimless, directionless, and goal-less.

Gould's army of mindless zombies.  Just ignore them ;-)

> Unfortunately "devolution" is a value-charged word.  It has
pejorative 
> connotations that imply evolving "downward" in complexity is less 
> desirable than evolving "upward."
> 
> If you use "devolution" to any great extent you'll sooner or later 
> provoke some irascible evolutionary biologist to sternly point out to 
> you that you are anthropomorphising evolution and injecting human 
> viewpoints of progress into it.  The "received view" is that
a colony of 
> bacteria is on the same evolutionary level as a colony of humans. In 
> fact, I've had it pointed out to me a number of times that bacteria have 
> been evolving since life began for exactly the same amount of time that 
> human beings have been evolving.

Using the term "devolution" seems to be permitted - even in politically 
correct circles - at least when you are talking about organisms 
undergoing complete mutational meltdowns.

Otherwise - as I'm sure both Gould and Darwin would agree - you must
"never say higher or lower" :-(
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