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Re: Re-evolving Therizinosaurids



Tracy Ford wrote (quoting moi):
>Bull, I'm thinking about real bones, not numbers that are given to bones.
Cold >numbers that are used in Cladist anylasis. How some bones will have
the 'same >number' but look different. Nature dosen't go by the numbers! It
> throws curve balls that Cladagrams can't account for.
        I must reiterate John Hutchinson's plea that you find out something
about what you are talking about. Yes, cladists use numbers to describe
character states. This does *not* mean that the analysis is necessarily
numerical. In the case of discrete characters, you may just as easily
substitute the word "primitive" for a zero and "derived" for a one, and the
effect is the same (although PAUP will not accept your infile). 
        Cladistics is about taking a large volume of data and processesing
it in a clear and efficient manner using parsimony, it is not necessarily
about numbers (let's not bring up indescrete characters, shall we?). It is
the same thing you might do in your head, only faster and more complete. In
any case, all of the zeros and ones which have you so confused are mere
symbols, to be tallied and counted and compared, not necessarily numbers.

>>        If you read the _Alxasaurus_ paper, you will note that the first
>>metatarsal of therizinosaurs is *not* "exactly" like that of other four-toed
>>dinosaurs, and actually (by some miracle of evolution) records its
>>re-evolution.
>Gee, that foot is incomplete, so am I missing something? Segnosaurus has
all >the metatarsals (4), so does Erlicosaurus, and a therizinosaurus. Did
you read >it?
        Yes, you are missing something. If you pay attention to the wording
above, you will not that I did *not* mention the pes of _Alxasaurus_ at all,
I merely said that this morphology was noted in the paper describing the
type of that taxon. Have you read my post, or the paper? Looking at the
pictures doesn't count, you know...

>      You really should stop getting all of your data from George ;).
>I'd take his adivce over any (please I'm quoting from Alan Charig, so don't
>flame me) frothing cladist, any time.
        Advice is your own business. Theory and data for models which wish
to claim scientific validity should be acquired from knowledgeable,
up-to-date sources.
        Anyway, let's just leave George out of this from now on, shall we?
       
        I do not froth, I effervesce. :)
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      Jonathan R. Wagner, Dept. of Geosciences, TTU, Lubbock TX 79409
      "The cost of living hasn't affected its popularity." - Unknown