RE: YOUR QUERY ABOUT HOW DIFFERENT APPROACHES AFFECT CLASSIFICATION
THERE ARE THREE RECENT ATTEMPTS TO PROVIDE AN OVERALL CLASSIFICATION OF
PROTISTS
CAVALIER-SMITH T 1993 KINGDOM PROTOZOA AND ITS 18 PHYLA.
MICROBIOLOGICAL REVIEWS 57: 953-994. THIS ONE RELIES HEAVILY ON SPECULATION
CORLISS JO 1994 AN INTERIM UTILITARIAN ("USER-FRIENDLY") HIERARCHICAL
CLASSIFICATION AND CHARACTERIZATION OF THE PROTISTS. ACTA PROTOZOOLOGICA
33: 1-51. ESSENTIALLY RETAINS MUCH TRADITIONALISM BECAUSE OF ITS
CONVENIENCE
PATTERSON, DJ 1994 PROTOZOAN EVOLUTION AND CLASSIFICATION. PROGRESS IN
PROTOZOOLOGY, PROC 10TH INT. CONG. PROTOZOOOL BERLIN. FISCHER VERLAG
(ATTEMPTS PHYLOGENETIC - INCIDENTALLY THEY TELL ME THIS IS OUT BUT I
HAVEN'T SEEN IT SO I CAN'T OFFER PAGES)
YOU COULD ALSO TRY MARGULIS' ET AL HANDBOOK OF PROTISTOLOGY BUT I DON'T
THINK THIS HAS ANY LOGICAL BASIS.
> 1. Earlier this summer Andrew Roger, David Patterson, and Mark Siddall
> debated the meaning of monophyly, and the value of the term holophyly.
> That got me thinking about phenetics and cladistics approaches to
> classifying protists. I'd like to provide the students with protistan
> examples of how different approaches to systematics results in different
> classification schemes. In particular, I'd like to use a) some examples in
> which the difference rests on whether or not one attempts to distinguish
> between common ancestry and convergence for some trait or traits, and
> b) some examples in which the difference rests on whether or not one
> attempts to distinguish between derived and primitive ancestral traits. Any
> suggestions?
>> 2. One set of traits of obvious importance would be plastid presence,
> type, etc. That chloroplasts have been lost often seems clear. The
> origin of chloroplasts is not so clear. The current trend in the literature
> seems to favor a
> monophyletic origin of plastids from some cyanobacterial ancestor, with
> secondary symbioses within eukaryotes (e.g., cryptomonads). Wolfe et al.
> (Nature Vol. 367, p. 566, Feb. 10 1994) have evidence of
> light-harvesing-complex proteins in red algal chloroplasts
> (Porphyridium), and Larkeum et al. (PNAS Vol. 91, 679-683, Jan. 1994)
> have evidence of chlorophyll c-like pigment (along with chlorophylls a and
> b) in Prochloron. So, is it reasonable to speculate that the photosynthetic
> prokaryote that became the first chloroplast could have had phycobilisomes,
> antenna complex proteins, and all three chlorophylls? Or, is it more
> likely that the use of certain chlorophylls evolved multiple
> times independently? Finally, how about the idea of a polyphyletic
> origin for chloroplasts, a la Dodge? Is that still viable?
I DON'T THINK THIS ONE HAS BEEN PUT TO BED YET
>> 3. F.J.R. Taylor and others have placed great emphasis on the morphology of
> mitochondrial cristae, but somewhere I read that mitochondrial cristae might
> assume a variety of shapes depending upon the physiological state of the
> cell at the time of fixation, as well as the method of fixation. What
> seems to be the current majority opinion on the value of mitochondrial
> cristae as a characteristic for systematics?
ALL EUGLENIDS HAVE THE SAME APPEARANCE OF CRISTAE, ALL CILIATES HAVE THE
SAME BUT DIFFERENT ETC. WITH CAUTION IT CAN BE USED AS A CHARACTER. IT
HAS BEEN DISCUSSED IN SOME OF THE LITERATURE - MOSTLY ON USING IT WITH
FREE-LIVING FLAGELLATES
>D. J. PATTERSON
