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Re: Transitional Fossils



>>        Every organism, therefore, is a transitional organism:
>>transitional between what immediately preceded it and what comes
>>immediately after.
>
>In cladistic methodology, NO fossils represent "transitional" organisms.
>Every specimen of every species, theoretically, is located at a leaf node,
>not a branch node, of a cladogram, and the transitional forms are relegated
>to the realm of hypothesis. How odd, therefore, that you still believe not
>only that transitional forms existed, but that ALL fossils represent
>transitional forms. (Unless you already know, somewhere deep down, that
>cladistic methodology is fundamentally flawed.)

The real problem here is the application of cladistics with respect to
evolution. Cladistics is a methodology for examining evolutionary
relationships. It is not a doctorine for dictating how evolution works. No
one would doubt that evolution has occurred (except the loonies - but they
don't count) and in an evolutionary history, organisms have to be
transitional between ancestoral and descendant organisms; it simply cannot
be any other way. Evolutionary history has given us an amazingly complex
four dimentional tree with millions of branches, twigs and leaves. Such a
concept is extremely difficult, if not impossible, for humans visualise or
perhaps even to comprehend. So we need tools that simplify that tree into
an understandable form and, currently, the favoured tool is cladistics. A
feature of the tool of cladistics is that it does not recognise
transitional forms, it is one of the main short comings of cladistics, but
it does allow us to test phylogenetic hypotheses which is its greatest
strength. So, while cladistics is very good at exploring evolutionary
relationships, it is lousy at exploring evolutionary histories because it
was never intended to do so. The next big step in systematics will be the
synthesis between phylogenies and evolutionary histories.

Cheers, Paul

pwillis@ozemail.com.au