Traits, states and cladists
Sat Nov 1 20:25:13 CST 2003
>In a good data matrix of (morphological) characters, what we call
>"character states" are actually not different states of one character, but
If they are in the same column you have already made the decision, right or
wrong, that they are homologous. I fail to see what difference the semantic
distinction will do to the concept of homology.
Sometimes one of the "states" is apomorphic
>and another plesiomorphic; in this case they are very useful for a
>phylogenetic-taxonomic study. Sometimes there are no apomorphies,
>and then we are appending phenetic noise to our analysis.
How would you determine if a character is apomorphic or plesiomorphic a
priori? In any case if a character only had a plesiomorphic state if would
be a waste of time adding it to the matrix. If all your taxa had the same
state what could you possibly achieve by adding this to the analysis?
>this is best for our computing: no distrust, no dobts, no suspicions
>about the resulting phylogeny reconstruction / classification.
A phylogenetic reconstruction and the data used to derive it are, in my
book, always under suspicion.
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