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Re: Terrapins: At Well Past 100, They're in the Mood
David Marjanovic (email@example.com)> wrote:
<Here we have the other discussion. The good Professor Spotila simply applies
Reptiles let their sex be determined by temperature.
Dinosaurs are reptiles.
Therefore dinosaurs let their sex be determined by temperature.
But his premises are trash, and the Linnaean system prevents him from seeing
this. See? This is how paraphyletic groups are positively misleading.>
Which is why scientific discussions on phylogeny are best suited for the task
when avoiding paraphyletic groups. This doesn't mean the "basal" groups are not
in themselves useful [historically], but that they are useless, as was stated
before by others, for the purpose of studying descent (which is what
phylogenetics attempts to do).
But the above logic goes further, much further:
It is not just that Spotila groups dinosaurs into reptiles, which is
technically true, but that he would group groups away from reptiles, which is
also technically true, though one would argue that birds ARE dinosaurs, or
descended from them, but ceased being dinosaurs once they arrived upon the
Earth. Then, one argues that birds can be all they they are, but that dinosaurs
never left temperature-determinate sexing, but that birds were able to surpass
this shows how unreptilian they are. This, however, should at least illustrate
the primary flaw of the argument:
Dinosaurs, while part of Dinosauria, are not the same as Dinosauria; to be
scientifically meaningful, "dinosaurs" MUST refer to Dinosauria and carry with
it the same baggage. The same is true of "reptiles" from Reptilia, and "birds"
from Aves (or Avialae, or Neornithes) or "avians" from Aves (etc.). People will
use the vernacular in different ways in different cases, and do this quite
frequiently, while at the same time using classification-based terms (not
phylogenetic ones) to refer to groups of organisms that correspond to their
groups. Reptilia suffers from the use of "reptile" and the classic paraphyletic
approach when confronted with the probability of avian descent within Reptilia,
but retain it for the classic view. Some (such as David Marjanovic) argue that
this classic view should be defined and the monophyletic view grant another
name, but this is a betrayal on the science of teaching and re-education errors
on the part of scientists in the past to think of descent and the mode of
speciation. This would be the perfect educational tool to show people how to
stop thinking in paraphyletic, typological terms, and get down to some real
This is why Spotila's argument above is actually wrong, since nowhere was the
use of dinosaur and reptile compared to one another in a scientific way, nor
are they being used equivalently.
Aside, of course, from the term "let", which would arue they choose
temperature as a determinate, whereas some reptiles can alter the organization
of their clutches to affect the sex ration therein, all of a-purpose it seems.
"Letting" nothing (passive action), "doing" everything (active action).
Jaime A. Headden
"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)
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