Tim Tyler  wrote in
news:c2ae77$1lq9$1{at}darwin.ediacara.org: 

> William Morse  wrote or quoted:
> 
>> And I will further note that non-adaptive lock-ins are unlikely to 
>> represent very many traits in old, widespread, morphologically stable
>> species, because such species are still subject to competition from
>> other species and have been for a long time. So they cannot afford
>> too much extra baggage. 
> 
> What if - after not very long - all their competition comes from other
> organisms with the same lock-in?
> 
> I fully expect this is the case regarding a number of old, widespread
> and stable adaptations - such as the genetic code.
> 
> I don't want to give too much weight to non-adaptive traits - but
> frozen accidents are certainly possible.

In another follow on this thread you mentioned that you might be accused 
of arguing both sides of the point. I think that you _have_ been doing 
that, and doing a right good job of it! One of Darwin's many good points 
was his ability to see both sides of an argument - you also seem to have 
this ability. I will now try to evince the same.

One of the key features of evolution is that it builds on previous 
successes, vs. reinventing the wheel at every step. The downside of this 
is that it is hard to go back. I seem to recall a recent article about a 
clade of insects (dragonflies maybe?) reinventing flight after having 
lost it. This was news because it almost never happens. So yes there will 
be frozen accidents. Lavers in discussing elephant ears notes that 
elephants don't sweat, perhaps because their ancestors  lost the ability 
during an aquatic phase (don't let Larry Moran know this!). Their big 
ears may only be a "contingent" adaptation. 


Yours,

Bill Morse
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