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

Re: ADV: Re: Classification: A Definition

>>>  > > I like the convenient of TOKOTs.  I prefer the name
>>>  > > "Brachiosaurus" to the specimen number FMNH P 25017.
>>>  > 
>>>  > How would defining "Brachiosaurus" *as* "FMNH P 25017" cause
>>>  > difficulty or information loss?

As Anthony Docimo already implied, only in that names are _far_ more
easily remembered than numbers.

>>If we're after mathematically supported phylogentic hypotheses by
>>whatever means, the actual cladistic analysis has to work from

Well, yes and no. Ideally a cladistic analysis should not be run
without taking variation within the population into account. Hennig
(IIRC) formalised this in the jaw-breakingly-named concept of
"character-bearing semaphoronts" - essentially, males should only be
compared to males and females to females in relation to characters
that are sexually dimorphic; characters that vary ontogenetically
should only be compared between individuals of the same ontogenetic
stage, etc. etc. A paper referring to just this issue arrived in my
inbox today (http://www.pnas.org/cgi/content/abstract/104/21/8731)
suggesting that many phylogenetically significant characters of
Catarrhini (Primates) are only present in males. I know that
recognising such variation in fossil taxa can be difficult, but it
remains a complicating factor, and cladistic analyses are better run
on populations than individuals.

And in reply to Mike Taylor and Mike Keesey - you're right, I wasn't
disagreeing with phylogeny as an ideal in classification. My idea was
that in cases where the ideal could not be met, that should not
prevent all development.


        Christopher Taylor