>RH writes:
>> A dog can only be a dog (a pure bred or a mangy mutt) but never,
>> never a cat no matter how similar the genetic code between the two
>might be.
>
>ED B:
>True, "never a cat," But that's not the evolutionary line that dogs come
> down from. Dogs are related to bears, genetically and shape-wise. And
>when you go back and look in the fossil record, what do you suppose you
>find? The "bear-dogs" of the Miocene.
Well, yes and no. Dogs, cats and bears all belong to the order carnivora. Men, fish, birds, dogs, cats, & bears are all vertabrates, which are all chordates . . . .
This taxonomic ordering orginally deviesed by Linnaeus divides the diversity of life based on observed similarties. Linnaeus was not himself an evolutionist, he was simply responding to the need for a way for workers in the life sciences to someway systematically classiby the exploding diversity of life they were discovering.
What is very important here is that 1) This entire structure assumes a tree like shape, and the farther apart animals are on the tree, the less characters they have in common and 2) after sufficient work had been done in paleentology, it turns out that taxonomic ordering tracks very closely the evolutionary pathways that were discovered. I.e., dogs are not only taxonomically closer to bears than to cats, but the fossil record confirms (as noted by Ed above) that dogs and bears also more recently shared a common ancestor.
Based on this an evolutionist would predict that detailed sturdies of biochemistry and molecurlar biology would show more similartities betweens dogs and bears than between dogs and cats.
I don't know of any studies (which does not mean they aren't there) specifically about dogs and cats, but there has been extensive work done on cytochrome-C and evolutioary distance of various animals/plants.
Cytochrome-C is a very very very very importand molecule in basic cell metabolism. Everything on earth ( except viruses, who use the host cells) I believe has this molecule. Due to its extremem importance and key role in cell metabolism almost any change in the molecule is deadly---so it can only evolove very slowly (assuming the evolutionary hypothesis true), since almost every modification will be deadly.
Thus there is little difference even from man to sequoia tree in the molocule--but there are differences.
And the differences track taxonomic distances which track presumed evolutioary pathways.
Roger, I'm going to transplant part of my sig file from my other provider to this post.
I think you need to go check out some of the WWW sites in the sig.
ttfn
mike in ca
Michael W. Fisher, USN ret. amateur philosopher, law student, general gadfly
The uiverse is not only weirder then we imagine, it is weirder than we can imagine. --G.B.S. Haldane--
Seen the creationist home page? Spend a pleansent 15 minutes exhausting all they have to show? Hear's the tip of the real science: http://cuiwww.unige.ch/w3catalog?evolution
If you should exhaust the resorces on the evolution page, here're some more links: http://muse.bio.cornell.edu/cgi-bin/hl-search
Here's some *more* bilogical resoruces: http://www.molbiol.ox.ac.uk/www/bio_www/index.html