Re: BAD vs. BADD (was: Re: Most popular/common dinosaur misconceptions)

[David Marjanovic <david.marjanovic@gmx.at>]

I wrote:

> so at every tryptophan codon in that gene there's a 50/50 chance
> that your cytoplasmatic ribosomes will just refuse to continue the 
> protein.

It's probably not 50/50. I don't know about codon usage in human 
mitochondria. (Usually when there are several codons for one amino acid, one 
is much more common than the others -- which one that is depends on 
phylogeny.)

----- Original Message -----
From: "T. Michael Keesey" <keesey@gmail.com>
Sent: Sunday, August 20, 2006 4:54 AM

> No. The length of a meter may be arbitrary, but, since it is the same
> in all circumstances, it is useful as a frame of reference. The same
> cannot be said of Linnaean ranks. _Struthioniformes_ and
> _Ornithischia_ and _Coleoptera_ are not somehow equivalent to each
> other simply because they have traditionally been cosidered orders.

Good that you bring up Struthioniformes, because this name also illustrates 
another problem of Linnaean nomenclature. Suppose we all agree on paleognath 
phylogeny. We will still use Struthioniformes in different names. Some have 
used it for Ratitae as a whole, others have restricted it to just the 
ostriches, and I think I've seen several intermediate possibilities in the 
literature. This is because Struthioniformes does not have a definition. OK, 
it is used as if it were defined as "whatever order *Struthio camelus* 
belongs to" -- but "order" is not defined, and this gives us splitters and 
lumpers. Splitting and lumping, except for species, is _impossible_ under 
phylogenetic nomenclature.

(Erm... it will be, once the PhyloCode will be implemented. At present you 
can make up definitions as you see fit.)