[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: Triassic birds
In a message dated 95-12-04 17:06:42 EST, Thomas_R_HOLTZ@umail.umd.edu (th81)
>The dinosaurian ancestry of birds has been highly corroborated by a dozen or
>so workers who have examined the primary evidence (i.e., fossils) in person,
>using techniques which have withstood examination in groups of organisms
>(insects, teleosts, mammals, etc.) with a much better fossil or modern
>record than dinosaurs. Given CURRENT evidence, it seems to better
>approximate the true phylogeny than any other suggested model.
>The BCF theory has not been subjected to the same tests, and as such, cannot
>currently be evaluated with respect to the "standard model". Until such
>time, it can securly be labeled "speculative".
There is a great danger that the cladists doing current dinosaurology will
become an inbred group, verifying and corroborating each other's phylogenies
by running more or less the same data matrices through more or less the same
computer programs and spitting out more or less the same cladograms. Thus,
having a "dozen or so" workers verify each other's work would really be like
having the same worker verify the same piece of work by replicating it a
dozen times. Not impressed.
And by the way, BCF phylogeny and BADD phylogeny agree almost completely on
the topology of the dinosaurian cladogram. They differ only in the
positioning of a few basal theropod groups and in the placement of
Ornithischia--significant but nothing major. BCF's non-computer method yields
substantially the same theropod phylogeny that BADD obtains by brute force.
The real differences lie in the interpretations of the cladograms, in not the
cladograms themselves, and since both interpretations deal with hypothetical
animals, they are equally speculative.