Joined: May 2006
|Most of the technical literature does not explore why comparative anatomy, for instance, is evidence for (or against) evolution, for the simple reason that it is not written from a theory-neutral perspective, but rather is written from an evolutionary perspective...From a theory-neutral perspective, what is it about the bat and horse similarities that are "deeper" and a "result fo common descent" ? Similarly, look here at the the flying squirrel and flying phalanger...Why are their similarities "superficial" and "appear not to have resulted from shared inheritance" ?|
I took the liberty of combining two of your "responses" there, CH.
You know, Mr. Hunter, I gave you a perfectly good reference for questions of your sort:
Vogel, Steven. (2003). Comparative Biomechanics: Life's Physical World. Princeton: Princeton University Press. You might also look at Vogel's earlier work "Life's Devices," again, by Princeton U. Press.
Organisms on this planet share common ancestry so far as we can tell, by every means we have available.
I'll assume you would call this view "theory-laden" as if it were a perjorative. Well, great, you're welcome to do that. Since you're a member of the DI, I'd say your views are quite likely to be "theory-laden" as well, as I'm sure you'll eventually demonstrate.
At any rate, Mr. Hunter...on this planet, organisms encounter a non-biological reality in the form of oh, ---- physics, chemistry, hydrodynamics, aerodynamics etc., --- which constrain and at the same time, create "optima" that CAN affect the trajectory of organisms and the shared inherited characteristics of said organisms ( like oh, pentadactyly and the fact that...oh, ...mammals .have SKIN), that have arisen , sometimes in similar ways .
Look at your instance of phalangers and flying squirrels, for example. Do they have gliding in common? Why, yes. Skin? Yes. Pentadactyly? Yes. Are they tetrapods? Yep. Biomechanically, there's not that many ways for mammals to glide, I'd say. Here's a sugar glider in action
and a flying squirrel:
(the flying squirrel is headed "west," sugar glider "east")
Other than the fact that they are using loose folds of skin called patagium to "glide" what similarities do you find so significant?
For instance, are the patagium of oh, say sugar gliders ATTACHED the same as in flying squirrels? No..the flying squirrel has little cartilaginous "spurs" that form a frame for the loose skin along the side of the body. This spur can be adjusted in angle which then results in greater or lesser tautness for the skin, aiding in "steering". In sugar gliders, the patagium attach from the "pinky finger" of the forelimb back to the first toe of the hind foot.
Skin would appear to me to be far more susceptible to evolutionary change than bones and the bones of the two animals in question are distinct in regard to this gliding adaptation, no?
Optima in relation to physical constraints in light of a common "bauplan" , eh? That common "bauplan" includes pentadactyly that is found throughout mammals and hence would carry a bit more "weight" , dont'cha think?
By the way, if this post seems a bit muddled, it's because I just woke up and it's 5:30 AM
AtBC Award for Thoroughness in the Face of Creationism