Joined: Jan. 2006
|First, the evolutionary claim is made that pentadactyl pattern found within mammals is the result of common descent. You do know that this means the common ancestor of mammals had pentadactyl pattern limbs. And that this trait is carried by ALL mammals.|
|No, it need not be carried by all mammals.|
Dood! Try to keep up here: pendactyly need not be carried by all mammals, if their limbs were "designed" to optimize their current functionality, but it is. Why? As we are reasonably entitled to conclude from looking around at current mammals, from reviewing the evidence from fossil mammals and the geologic contexts in which they are found, and from the genetic molecular and developmental evidence, the pendactyly we observe among all extant and extinct mammals is the result of common descent. This is a prediction of evolution that's contra "intelligent design" (or, as we respectfully and civilly call it around here: sheer IDiocy...).
If some lineages of mammals are around long enough, and the adaptive pressures are powerful and persistent enough, maybe the outward phenotypic indicia of pendactyl ancestry would eventually disappear (the tippy-toes of horses, the back ends of whales, a strain of eight-toed cats or--more far-fetched, six-fingered psychic humans...).
The developmental and genetic indicia of ancestral pandyctyly would linger on for many ages but, after the passage of sufficient time, perhaps even those signs would be covered over by the palimpsest of later changes.
Arguably, however, it would take a very long time indeed for all traces of common mammal heritage to disappear, just as mammalian inner ear-bones may still be traced back to earlier quadruped jawbones, pandyctyly itself can be traced back to a "frozen accident" or early set of selections among the variant digit patterns seen in the earliest transitional tetrapods, and vertebrate body plans can be traced back to duplications of the urbilaterian Hox tool-kit.
If you have some kind of point here, not obscured beneath your verbal vagaries and determination to avoid the obvious implications of the evidence, it has so far failed to surface.
Either get on with it.
Or admit there is no actual "it" wherever you are at.