Hi Corey,
The real bones are too heavy for display - the bones are die cast (I don't know if that's the proper terminology) and the skeletons on display are made of lighter materials.
This is true, most of the time. The mounts in Carnegie are the actual mineral supported by steel bars. However, whether these Triceratops fossil displays are original or cast, they still represent independent finds...they are not all casts off of the one Carnigie sample.
The Ceratopsian family is wonderfully broad. Yet scientists do not see each different species as a series of points along a chronological sequence of linear evolution. However, some scientists say that these fossils represent non-linear contemporaneous branches on some tree...
This whole subject of how evolutionary relationship is percieved and determined is an interesting one for me. For instance the term convergent evolution produces no real information about the natural world, but is actually uninformative evolutionary word-stock used to label any apparent similarity observed in unrelated species. Terminology like "Convergent Evolution" is not at all a pentrating idea with the ability to explain these similarities...it merely inteprets their existance as some inevitable product of evolution. This is because to an evolutionist all relationships, close or distant, are evolutionary relationships. Evolutionary biology's highly specialized lexicon of intepretive language is obviously not found in the external natural world, and so must originate from internal superimpositional beliefs about the natural world.
On the subject of evolutionary relationships, and out of curiosity fueld by this thread, I cracked open my copy of Horned Dinosaurs, written by Peter Dodson, and recognized as one of modern paleontology's definitive works on Ceratopsia. In particular I want to share a much abridged version of the chapter titled Sisters, Cousins, and Aunts: Deciphering the family tree. The exerpts I am selecting help depict a brief history of constructing the family tree for the Triceratops...and then deconstructing...and then reconstructing it. Actually, I believe these exerpts show how subjective and quite frankly, how predisposed to evolutionary doctrine this practice is.
Peter Dodson...
Fossils do not come out of the ground with labels on them. Defining and naming species and genera is a major intellectual activity.
Marsh identified the first remains of a horned dinosaur as Bison horns in 1887. When at last he finally got it right, naming Triceratop Horridus in 1889, Marsh compared the animal to Stegosaurus, a favorite of his from the late Jurrasic Morrison Formation that he has named in 1877. Only as more specimens and more taxa were described did it become evident that the Ceratopsia represent a distinct group by themselves.
The discovery of protoceratops in Mongolia 1922 proved to be truly electrifying, and it was recognized immediately by Osborn as "the long-sought ancestor" of Triceratops. Psittacosaurus too was a fruit of the AMNH expeditions to Mongloia, but it was a remote cousin, all but forgotten...only admitted into full membership in the Ceratopsia in 1975.
An important synthetic activity of the paleontologist is the determination of relationships.
Clear ancestor-descendant relationships are not unequivocally preserved.
It would be most convenient if a lenghty series of time-successive formations were found in sedimentary basin, each with a descendant species of genus of Dinosaur, but this is not found in practice...much of the evolutionary activity thus may have gone on "off stage", perhaps in upland areas closer to the mountain uplifts, which are not well represented in the fossil record. Presumably new kinds of Dinosaurs then migrated down into the lowlands. This is an interesting model, but one for which there is as yet little emprical evidence.
The first attempt to review all of the Ceratopsia was in 1907...
Dodson goes on to describe the 20th century history of Ceratopsian acedemia...each step much like groping in the dark...sometimes a scientist making a contribution that sticks to the wall chart, and at other times a succesive scientist is undoing the cherished work of a predecessor.
Fair enough...
Now on the newly evolving science of cladistics he informs the laymen For a number of years there was acrimonius debate about the merits of the cladistic method compared to the more classical methods used by systematists for the previous two centuries. Today there is general agreement, whether one or not subscribes to all aspects of cladistic philosophy, that the methodology of cladistic analysis is a useful one. Briefly, cladistic attempts to reconstruct evolutionary novelties---derived characters or synapomorphies, in cladistic jargon.
There is just one final point to make before proceeding. It makes no difference at all to a chicken or a pigeon or an ostrich whether we call it a bird or a dinosaur. It is useful for us to be able to make generalizations about the organisms we wish to discuss. But the names we choose to discuss them are pure human artifacts...the term 'Dinosaur' is a human construct, not an objective fact of nature...we can define our "Club Dinosauria" more broadly or narrowly, and it makes no differenceto the animals inside. It's a matter of taste, not of science. And good taste never goes out of style!
Cladistic analysis began to be applied to dinsaurs in 1984...for our purposes I wish to consider Seron's analysis, particularly the part that relates to ceratopsians.
The origin of Ceratopsians had long been a problem...Sereno came up with a novel arrangement that links the Ceratopsia with the Pacheycephalosauria (the dome-headed dinosaurs) as the Marginocephalia (shelf-heads).
The only other cladistic analysis of the Ceratopsia as a whole was published by Philip Currie and me in 1990. We countered Sereno's suggestion of paraphyly of the Protoceratopsidae by suggesting, albeit tentatively, three potential derived characters uniting protoceratopsids...the matter is unresolved, and the anatomy of the skull Montanoceratops, putatively the most highly derived member, is inadequately known.
The foregoing discussion provides an overview of ceratopsian relationships using the most powerful and respected tools of the trade. Why stop there? Fools rush in where angels fear to tread...Evangelists for cladistics insist their technique is the only one that can yeild objective, reliable results, but it is also true that cladistics requires prior knowledge and makes certain explicit assumptions.
I apologize for the extensive quoting, but I am aware how easy it is to take a writer out of context, and I wished to minimize that risk. It bears repeating that these quotes were from a single chapter and not cherry-picked from various sources.
Also it needs to be said that my point here is not that Peter Dobson is being dishonest as an evolutionary scientist. On the contrary I find him to be refreshingly candid about his approach to dinosaur science, and feel that his writing is unpretensious and upright.
My point is that what the fossils "tell us" is really what the scientists tell us. And what they tell us is based on what their world view tells them. I find many evolutionary thinkers will readily admit to their bias...they feel confident in doing so because, in their honest opinion, materialistic uniformitarianism and evolutionary biology are the only intellectually viable candidates for truth...and that the only possible alternatives; intelligent design and special creationism, deserve no place at their table of professional speculation.
MC
