[Taxacom] burn out (was: classification of Class Rosopsida)

Alexander.Schmidt-Lebuhn at biologie.uni-goettingen.de Alexander.Schmidt-Lebuhn at biologie.uni-goettingen.de
Wed Apr 22 05:02:43 CDT 2009

Richard Zander wrote:
> The reason some of us insist on paraphyletic taxa is because evolution,
> if defined as descent with modification, is described only by
> paraphyletic-autophyletic series, where the paraphyletic taxon is the
> descendee (ancestor), and the autophyletic taxon is the descender.

Dear all,

already wrote something about this off-list, but once again:

The ancestors as individuals are dead anyway. Quite logically, extant
reptiles are not the ancestors of birds. Extant apes are not the ancestors
of humans. Etc. As a group, and that is what we are interested in, the
ancestors did not survive as a paraphyletic (and completely static,
unevolving) taxon, while somehow a new group appeared out of the blue of
which they are nevertheless the ancestors. Instead, the ancestors who were
reptiles survived as both reptiles and birds, and the ancestors who were
apes survived as both apes and humans. Seen this way, it is the only
logical consequence to place birds in the group reptiles and humans in the
group apes. Seen this way, monophyly describes best what happened in the
course of evolution.

It is really important that people think this through. Illustrating
evolution with paraphyletic groups actually leads to a lot of
misconceptions especially for laypersons, starting with "we are descended
from monkeys" (no: we ARE monkeys) and ending with "is it not amazing that
there are more species of genus X than of genus Y?" (no: you can only
compare sister groups or maybe clades of exactly the same age, but genus
is simply an arbitrarily assigned rank).

Alexander SL

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