VIII. TAXONOMY

Please read the three papers I gave you first. Then, Just casually compare the taxonomic schema. Many revolve around the algae. This reflects the fact that I have more papers around relating to algae than I do relating to any other large taxon (it does not reflect significance). In the process of comparing--note that there are similarities and differences not just in the types of organisms, but also in the types of taxonomic schema. Nature's whims produced the former, scientist's perspectives and needs produced the latter. Why they exist is important, the details that differ are not. Who is "right" and who is "wrong" usually depends on what is being considered.

In the very recent past phylogeny (the business of seeing taxonomic relationships as relating to evolutionary developments) usually produced a tree-like diagram. It served the purposes at hand. Now, it is so inaccurate a model for evolution that a "wagon wheel" with its axle attaching it to a sort of deformed tree, often replaces it.

Historically, taxonomy has been based on morphology. (Check the frog morphology paper , infra.) This permits one to pretend that evolution is not involved. It just a way of conveniently grouping things that happen to have similar characteristics --- that you can "see". Through the last century this fiction permitted the study and discussion of phylogeny (evolution) while avoiding additional "Scope’s" Trials. But it gave credence to some of our worst prejudices (check the Taung baby)..

Trouble is, the dependence on morphology drove folks in microbiology crazy because it produced the sphere/rod/spiral bacterial taxonomy that could not possibly work. I, personally, give the microbiologists of the world credit for putting an end to the notion that morphology is sufficient for taxonomic classification. This revelation proved to be a boon for those who work in aquatic systems. One rarely "sees" the most important creatures in an aquatic system (plankton and submerged forms). Thus, until the microbiologists got ugly about morphological taxonomy, there was no real "taxonomy" of the most significant aquatic creatures (fish, whales, and macroinvertebrates were considered only if they served as lunch).

Microbiologists can no longer rely on the word, "bacteria", and phycologists can no longer rely on the word, "algae" to designate a scientifically identifiable group. Yet, if you accept only terms such as Cyanobacteria, MOST of the very real body of information about blue-green algae will be unavailable.

 

1. Just perusing the pages. These are "old", but taxonomy should NOT be changing---should it?

- Moore, R. and B. Rushton. 1979. The major biological taxa. Carolina Tips 42:45-47. An easy beginning. Start here.

- Dixon, P. 1970. A critique of the taxonomy of marine algae. Annals, New York Academy of Science 175:617-622. His criticisms apply to just about any taxon. Note his "aims".

- Christensen, T. 1964. The gross classification of algae. Algae and Man (ed. D. Jackson) 59-64. An example of the kind of open-ended argument in which taxonomists indulge.

- Lewin, R. 1974. Biochemical taxonomy. (Just read the list, it boggles the mind.)

Do not forget that Margulis's paper (last week) differs from most of these. Figure out how/why. In most situations in our field surveys, it really does not matter which of the schema you employ. Most work in most situations. What matters is that you appreciate that there are incredible numbers of acceptable, reasonable, phylogenetic breakdowns. None of the enclosed is an inexpert job, but I have barely scratched the surface in terms of highly respected schema. It is likely that I would ask you something intended to generate thoughts about why the variety exists. What distinct purposes are served. Whittaker’s five kingdom system seems to be the most popular at the moment. It melds well with the Endosymbiont theory. I personally favor it when communicating with undergrads. You are stuck with my bias toward Margulis’ interpretation but remember that these two do NOT really disagree in broad taxonomic terms. (Check the web info.) The Margulis; work is not simply taxonomy, or even phylogeny. It is an exceptionally well-based analysis and description of the biochemical evolution of life (which just happens to produce an exceptionally rational, phylogenetic-based, taxonomic scheme).

YOU MUST - find a copy of "Ward and Whipple" (that's its nickname, but most limnologists actually do not recognize its correct name--FRESH-WATER BIOLOGY 2nd Ed.--I have been told that there is a third edition, but I have not seen it.) Ward and Whipple edited the first edition, W.T. Edmondson (Lake Washington, "phosphate in winter") edited the second. If you cannot find a convenient copy, I have one in the lab. Look thru it. It is one of the most functional sets of "keys" extent. It may save your job some day. It includes very brief (and VERY authoritative) descriptions for each taxon covered. I consider this a critical reference, one you must remember.

*Maley, L. and C. Marshall. 1998. The coming of age of molecular systematics. Science 279:05-507.

*Goodfield, June. 1984. Dr. Coley's toxins. Science84 (April) 68-73. Anecdotal evidence is not all nonsense. It is just not well sorted out. Should we get rid of all genuinely damaging infectious disease organisms? Smallpox? Ebola?

*Brock, T. 1968. Taxonomic confusion concerning certain filamentous blue-green algae. Journal of Phycology 4:178-179. Blue-greens are "blue-greens" when they contain chlorophyll a and "bacteria" when they do not.

---Or, they are bacteria because they are Prokaryotes and some taxonomists do not sufficiently distinguish the terms "bacteria" and "Prokaryote"

---Or. . . .

*Kollar, E. and C. Fisher. 1980. Tooth induction in chick epithelium: Expression of quiescent genes for enamel synthesis. Science 207:993-995.

Just when you thought it was safe to go back into the Petri dish. From this paper forward, you will be able to "one-upmanship" all manner of smart Alec. Just wait, someday someone will respond sarcastically to some speculative comment you have made by saying, "That's about as likely as hen's teeth". At that point you can drive them crazy by trying to explain this paper.

*Cherry, L.; Case, S., and A. Wilson. 1978. Frog perspective on the morphological difference between humans and chimpanzees. Science 200:209-211.

(Read it twice then file your ego in a closet and consider how much a bias can louse up science.) This particular myopia allows us to destroy ecosystems and write-off species. We have quite a few convenient notions along this line. It is important that you recognize the bias which the authors have illuminated. Which is more significant, morphological or biochemical distinctions?

*Lewin, R. 1985. The Taung baby reaches sixty. Science 227:1188-1190. Another "frog" perspective. (Why?)

*Field, K.; Olsen, G.; Lane, D.; Giovannoni, S; Ghiselin, M.; Raff, E.; Pace, N., and R. Raff. 1988. Molecular phylogeny of the animal kingdom. Science 239:748-753. This approach will ultimately squelch all the arguments. Can you see why? How does it really differ? (Compare Lewin, 1974. That is 14 years earlier.) This is the genesis of the "evolution" papers emphasizing the Archaea - from last week.