Darwin (was: Phylogenetic evidence)
rjensen at SAINTMARYS.EDU
Thu Jul 25 08:47:40 CDT 2002
SKÁLA Zdenìk wrote:
> I must disagree (despite I like most points that Pierre made). The clade definition does not exclude character-state reversals, so there can exist clades (and do exist - usually the large ones) whose members do not share any single character state in common. Consequently, the clades are not classes but objects defined by a distance/similarity measure like clusters in cluster analysis.
If I take this literally, then you are arguing that there can exist a clade in which the objects have absolutely nothing in common ("...members do not share any character state in common..."). If that's the case, then the "clade" does not exist - it cannot be supported by any evidence and, in my mind, consists of two mutually exclusive classes of unknown affinity.
Can you provide an example of such a clade?
Richard J. Jensen TEL: 574-284-4674
Department of Biology FAX: 574-284-4716
Saint Mary's College E-mail: rjensen at saintmarys.edu
Notre Dame, IN 46556 http://www.saintmarys.edu/~rjensen
More information about the Taxacom