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Re: Dinosauria---Rejected Name?



> <It is important to remember, in such discussion, that a clade is not a
> group, it is a monophyletic entity, and clades are indicated by an
anlysis,
> not fully discovered. [...] clades are
> named with the intention of discovering the known descendants of the
> specified common ancestor.>
>
> So, 'a clade is not a group, it is a monophyletic entity...'. I suspect
this
> means that the composition of the clade may be changed without changing
the
> name.

At first it means that a clade is a philosophical entity and not a
philosophical class. You can take a clade at its root and hold it in your
hand, and it doesn't fall apart. You can't do anything comparable with a
Linnaean taxon. You can only take the box that contains a Linnaean taxon and
hold that (labeled) box. If you leave the box away, the species fall
independently to the floor. All clarities removed? :-)
        The _known_ contents of a clade can indeed change as much as those
of a Linnaean taxon. The _real_ contents* of a clade are totally immovable,
_unlike_ those of a Linnaean taxon, which doesn't have a fixed definition.

* Here is of course where all those words like discovery, hypothesis,
science etc. come in.

> If so, the entity is a construct built more on expectation than
> observation; if the entity weren't expected to continue to exist, it could
> be disbanded.

No. As long as the observation that evolution occurs is considered correct,
clades either objectively exist or objectively don't exist (the latter can
happen with qualifying clauses or when a stem-based clade has more than one
internal anchor).

> Also, 'clades are indicated by an anlysis, not fully discovered.' and
> 'clades are named with the intention of discovering the known descendants
of
> the specified common ancestor.'
> The supposed 'descendants' of an actually hypothetical ancestor are
included
> because of an analysis, an inference which may not be correct ('not fully
> discovered').

True. So what. Words like hypothesis and science apply here. See below.

> Then '...clades are named with the intention of discovering
> the known descendants of the specified common ancestor.'  So, as I
> understand it, the intention to do further analysis qualifies the analyst
to
> name [...] [clades] for general usage.

Yes. Another justification to name a clade is the necessity to discuss it,
of course.

> his/her hypothetical entities

The _entities_ are _not_ hypothetical (as long as evolution is accepted).
Their _contents_ are. This is not the same. I can take _any_ two organisms
and use them as the anchors for one node-based and two stem-based clade
names; all three clades _have_ some contents, even though maybe not more
than one of said organisms (the stem-based clades) or both (the node-based
one).

> Finally, though the analysis is not necessarily complete and correct ('not
> fully discovered') the author says, 'the natural ordering of life (through
> phylogenetic relationships) is discovered...'  That's a very definite
> statement which appears to contradict some prior statements.

Because you quote it out of context. :-) Clades are discovered rather than
invented, so basic cladistic philosophy says. "Not fully discovered" refers
to the additional fact that many of these discoveries give clades wrong
contents.

> Just one other quote:
> '...a phylogenetic name ALWAYS refers to the same clade, and therefore the
> same included species.

Clarification: the same species that REALLY, and not only according to
someone's hypothesis, belong to it.

> The crux of phylogenetic nomenclature is that the
> included species are HYPOTHESIZED...'

Means again: Because we don't know what species REALLY belong to it, it is
anyone's guess, er, hypothesis which do and which don't.

Hope this helps! :-)