[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: WHAT'S GOING ON?



<Cladistic trees do not give direct ancestor-descendent relationships on the
large scale, they can only give more vague relations because human
scientists were not living back 600 million years ago to witness the birth
of animals; the only way we can be scientific is by not explicitly positing
ancestor-descendent relationships, and letting the trees speak for
themselves.>
I hope you will clarify this a bit.  Cladistic definitions are stated in
terms of ancestor/descendants.  I think you mean that one known animal is
not necessarily ancestral to another known animal, but I want to be sure.

<By not including birds within dinosaurs we are going back to the days of
typology where birds were seperate from everything else on the planet (as
were dinosaurs).>
Isn't a choice made about what group gets a separate name?  You could
presumably have only one group allowed for all animals and plants, but
people have chosen to identify some sets of animals and plants separately.
The source of the connection in these groups is evolutionary and rules for
naming are established, but is there anything necessarily anti-evolutionary
about calling birds a separate group?
Thanks.

----- Original Message -----
From: "Matthew Troutman" <m_troutman@hotmail.com>
To: <kinman@hotmail.com>; <dinosaur@usc.edu>
Sent: Friday, June 30, 2000 11:41 AM
Subject: WHAT'S GOING ON?


> <<Although I don't like the Feducciaries and their disdain for cladist
> analysis, I also don't like the strict cladists and their disdain
> for selective eclectic classification.>>
>
> Actually Ernst Mayr is a bigger (and probably more effective) critic of
> cladists than Feduccia will ever be.
>
> What is selective eclectic classification?  (Sounds like an oxymoron.)
>
> <<When strict cladists respond in this way, and infer that someone
> doesn't know the difference between dinosaurs (sensu stricto) and
dinosaurs
> (sensu lato, i.e., including birds), I think they hurt not only
> cladistic classification (which I use up to a point), but also cladistic
> analytical methods (which I find very valuable).>>
>
> How?  The driving force of life is evolution.  To exclude birds from the
> rest of dinosaurs is not an evolutionary perspective.
>
> <<This insistence that the rest of world recognize their terminology,
> and making fun of those who don't distinguish between dinosaurs (sensu
> stricto) and a cladistic dinosauria (sensu lato), will only backfire, and
I
> would discourage such tactics.  I could care less if it turns people  off
to
> strict cladistic classification, but when it casts a cloud over  cladistic
> analytic methodologies, then it really starts to irritate me.>>
>
> Without getting myself involved in whatever matter you are discussing let
me
> give you some historical perspective on cladistic vs. Linnean (or
whatever)
> classification:
>
> As I said above, cladistic classification is grounded in evolutionary
> thought, where everything shares a common ancestor at some point on the
tree
> of life.  Defining groups by their common ancestry is not only convenient,
> it makes sure that we will not be excluding organisms from the group in
the
> future, it is also evolutionary.  We have a more accurate picture of life
> and how it changed because rather than vaguely tracing ancestries and
> lineages on the Linnean chart (or whatever), we can identify where, for
> example, birds and cabbages had their last known common ancestor.  We
can't
> do this as well in Linnean (or whatever) classifications.
>
> Linnean classifications were popular for a couple hundred years.  The
reason
> they were so popular for the first hundred years of their existence is
> because they lent themselves to the predominantly non-evolutionary
> classifications of the 18th and 19th centuries.  Birds and reptiles sat on
> seperate ends of the Linnean chart seperated by a gulf seemingly larger
than
> any systematist could bridge.  Essensialism (going back to Plato),
> archetypalism, and typology, non-evolutionary theories of thought were
> easily accomodated by the Linnean system.  Since relationships weren't
> inferred by Linnean taxonomy, essensialist, non-evolutionist, systems such
> as typology could be utilized to their full potential; there would be no
> muddy areas in the chart where reptiles changed into birds, the basic
types
> (the very root of the word typology) would never change.  The very face of
> nature, that is evolution, would be ignored.
>
> Linnean classification could be converted over to evolutionary
perspectives,
> but things get confusing:
>
> Say I have a small proto-animal, lets call it _Tyler durden_.  It is the
> sole member of the family Tyleridae.  Now, we know that this animal is the
> closest thing to the Kingdom Animalia; it is *almost* an animal, but not
> quite.  One of the first animals is _Marla singer_, seperated from _Tyler_
> by being in the rank of Kingdom instead of Family.  From the cladistic
> perspective, _Tyler_ and _Marla_ share a common ancestor but _Tyler_ is
> excluded from the group _Marla_ is in by the fact that she has an ancestor
> that _Tyler_ does not have.  On a Linnean chart, such relationships are
> difficult to convey because they are not inherently evolutionary,
cladistic
> classifications are by their nature built to convey evolutionary
> relationships.  This is why they are so successful; their structure is not
a
> simple catalouge, they are a tree showing the relative evolutionary
> relationships of one group to another (and so on).  Cladistic trees do not
> give direct ancestor-descendent relationships on the large scale, they can
> only give more vague relations because human scientists were not living
back
> 600 million years ago to witness the birth of animals; the only way we can
> be scientific is by not explicitly positing ancestor-descendent
> relationships, and letting the trees speak for themselves.  Only with
> greater magnification on the branches of the tree (and perhaps the
> physically impossible time machine), can we tell ancestor-descendent
> relationships.  Until then, we have to be scientific and say only what we
> know for sure.
>
> <<Making fun, explicitly or implicitly, of those who don't specify
> "non-avian  dinosaurs" should realize that it is not longer humorous, and
> the point they may trying to make is counterproductive.  Alex was looking
> for information, and all he got was implicit criticism, and I don't think
> this is helpful.>>
>
> I haven't read the message that read up to this, so I won't comment on it.
>
> Anyway, saying "non-avian dinosaurs" is the scientfically accurate way of
> describing what classical dinosaurs are.  By not including birds within
> dinosaurs we are going back to the days of typology where birds were
> seperate from everything else on the planet (as were dinosaurs).  We most
> express things they way that they are, evolutionarily.  To exclude birds
> from dinosaurs, not being in keeping with the evidence at hand and
certainly
> not looking at it evolutionarily.
> Matt Troutman
> ________________________________________________________________________
> Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com
>