Phylocode: Light, not heat
Benjamin J. Burger
bjburger at AMNH.ORG
Thu Mar 7 17:34:24 CST 2002
If Phylocode is going to be a working model it must address a few key
1) A Monophyletic clade includes a most recent common ancestor plus ALL and
only ALL of its descendants.
(the basis of a Phylocode grouping)
- rarely do we have all the descendants of a clade, plus we don't know what
will evolve in the future.
- From the view of a paleontologist, phylocode must be linked to a time
- Most biologists use the present time period to define the ending point in
the search for ALL descendants.
- But paleontologist will have to link phylocode to a time period, or have
older fossil groups belong to
higher hierarchical groupings than younger fossils.
2) Phylocode is highly unstable because every other week or so some yahoo
publishes a new cladogram, which might change the current classification.
Not a bad thing but who is going to try a keep track of all those new names.
3) Phylocode is a exploding hierarchical classification system, each branch
is a potential grouping.
Thus we could end up with about 30000000000 levels (all species that ever
existed minus 1) to a Phylocode hierarchical system.
4) Consently changing hierchial classification schemes are difficult to
maintain in a relational database.
The emerging field of bioinformatics and the explosive growth and access to
DNA-sequence data, large morphological data sets and faster bigger
computers, will mean that Phylocode will be swallowed up by some massive
relationally organized super matrix of species, and the Linnean-based
hierarchical view of classification will be only remembered in history
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