Discussion in 'Codex taxinomiae plantarum (CTP)' started by Braem, Nov 19, 2006.
Or, the whole is greater than the sum of it's parts.
They "stole" the word from the German language: but in German you write it with upper case "G" : Gestalt.
Not really, in nature one plus one = two .... anything else is imagination and not scientific.
Victor et alia,
here a few answers to your counter points. I have not figured out yet how to edit those things the way you do. Maybe someone can tell me.
1) If anyone, novice or not puts a Phragmipedium, a Paphiopedilum, a Cypripedium and Mexipedium xerophyticum (whether in flower or not) on a single table and uses his/her eyes, he/she will readily recognize that all these are different.
2) Put a Mexipedium side on side with a helenae. That will do the job. The small cyp ... same thing .... not in anyway alike in any aspect.
3) It is true that hangianum and druryi are different. So what. Mexipedium is unique by its habit as well as by its flowers. There is NO other slipper that is in anyway comparable with Mexipedium.
4) The notion that the parvisepalums (delenatii group) are to be put together with the brachypetalums (bellatulum group) was for a very short time propagated by Cribb. He was also the one that claimed that P. armeniacum is a variety of P. delenatii and he also propagated that the parvisepalums are a link between Cyps and Paphs.
all you need to do to differentiate between the parvisepalums and the brachypetalums is to look at the pouch. Pointed pouch = brachypetalum, non-pointed pouch = parvisepalum. Of course there are a number of other criteria that can be used. For example the leaf morphology. One look ... that suffices.
I wont comment on "evolution" in the slippers, because I don't want to comment guesswork.
5) As far as your practicality example is concerned. Sorry, but when I see a slipper orchid, I can tell you what the related species are without consulting a lab.
More later ...
You certainly have a 'feeling' for your organisms, but taxonomy (supposedly) should have a scientific basis. According to you too. That means, to me, that you need characters that can be used in keys. I am becoming a broken record here. If we were chatting in a forum on grasses or crucifers instead (e.g.), we'd be *really* concerned with diagnostic criteria that one can actually find written down on paper. But even though we are talking slipper orchids, that does not make these plants immune to the sundry aspects of a good classification: good (useful) circumscriptions around taxa (be they genera, species, etc.), and names with proper priority to match them. Just because a Mex and a given Phrag, a Paph, and a Cyp might be 'diagnosable' by the untrained eye, that doesn't abrogate the need for a formal, keyable, slipper orchid classification. So, why not get off the gestalt thing, and just go for key characters? One can suggest quite fine key chars. for a single conduplicate-leaved genus, or one can make a nice key for Mex, Paph, and Phrag. I suppose keys become more difficult at the slipper species level, however... though some have tried.
Well, parvisepalums aren't a 'link' between cyps and Paph, but being basalmost in Paph, they may have inherited some chars. in common with the common ancestor of Paph, Phrag, and Mex (which I have already described as probably having the inflated pouch character). 'Missing link', no, but both Chen and Cribb made just a little sense when they suggested such things. Not a very good way Chen put it, however.
Evolutionary research = guesswork? That's a funny one!
Finally, glad that you know what the 'related species are' when you see a plant, but I'm not even sure what a slipper orchid species is!
Best as always
It's a philosophical statement, Guido.
I did realise that :evil:
I think we agree on many points. No question, taxonomy should be put on a scientific basis. And it is. If I base taxonomy on leaf structure, flower structure, form of pollinia etc. etc., it is a scientific basis.
And you use the "keys" again. Of course you are right again, you must be able to key out your taxa. But we have been doing that ever since good old Linné tought up the binominal system. Behind my back, on my book shelves, I have plenty of keys. And they are all based on alphataxonomic characteristics. Look at Braem; Braem & Chiron; Cribb; Schmeil-Fitchen, Schlechter, and the many textbooks for botany. The keys in those books work. So, where is the problem?
I have, however, a problem with creating (I hate that word) a key and to leave out on-time characteristics. If you take Hispaniella henekenii in the Oncidiinae, the key you can start off with is :
1) flower looking like a bee .... Hispaniella henekenii
there is no other plant in the Oncidiinae that matches that other than Hispaniella. So where is the problem?
Now to my funny statement: can you please give me one piece of single evidence that is reliable (fossil record, or whatever) enough to allow a decent statement about the evolution of orchids. Maybe I missed something somewhere. And if so, I would be glad to be shown that I did miss something
OK enough informally, but one should still be able to key it out formally! And in this case, this should pose no problem so long as one defines Oncidiinae first with key characters.
Ah, I think we may have been 'talking past each other'! Do you mean the evolution of orchids in the sense of their origins from monocotyledonous ancestors? The actual evolutionary steps that took place millions of years ago? The actual morphological changes, i.e., that occurred? I have mainly been speaking about evolution in terms of reconstructing the history of orchid lineages, i.e., phylogenetics. We do indeed have tools from (probably especially molecular) developmental biology that can HELP us to try to reconstruct how morphologies may have evolved in the past, but these will only generate hypotheses, maybe strong and very interesting ones, but only hypotheses. There is, as you say, nothing in the fossil record that can give us any direct evidence. So, e.g., the hypotheses about inflated pouches = primitive in slippers from my earlier posts i a hypothesis that matches both the phylogeny and a look at how flower buds develop.
Hope this helps.
yes. It seems to be the case. The problems I have are (for example): what is the proof that low chromosome counts are the primitive form? or where is the proof that inflated pouches are primitive? or that the single-flowered species are promitive etc. or vice-versa
The phylogenetics are indeed the interesting part. I remember a paper from the late Jack Fowlie on the evolution of the slippers and Wallace's line in the Orchid Digest, for example. Jack was a great guy, but ...
So what I mean is: where is the proof that cyps or more primitive than paphs or phrags or vice versa.
Evidence leads to inference. In the case of evolutionary biology, we cannot seek proof unless we are working with E. coli strains (or similar) in completely controlled conditions, and still, this isn't as exact as solving the crystal structure of a protein.
I think we should go over what primitive means in the context I've used it. I do not mean primitive, e.g., in complexity, in the sense of a single celled amoeba versus a human. When one uses the term primitive in a phylogenetic context, it simply means further and further back on a particular tree in terms of 'nodes' (branching points) from the root (where the tree 'begins').
I'll use the 'inflated' pouch characteristic as an example. Inference of 'primitive' simply follows from where traits appear on the hypothetical tree of slipper orchids. Given that the slipper tree is 'rooted' at Selenipedium, and that that one node up is Cyp, and then one node up is, for now: (Paph + (Mex + Phrag)), and within Paph: (Parvi + (Brachy + the rest)), and within Phrag: (Micro (+ rest)), and that the distribution of 'inflated is:
- parvi Paphs
- micro Phrags
....then one most parsimoniously infers that the tree nodes in between all the inflated guys, you can think of them as hypothetical ancestors, had the same trait as well.
Not proof; but most-parsimonious inference based on a phylogenetic hypotheses, itself derived from empirical data. Remember, 'primitive' here referes only to the inference that *further up* in the slipper tree, in terms of tree nodes, one infers that fly pollination evolved several times in parallel. Primitive here only refers to the positioning (in this case by parsimony inference) of where observed characteristics 'started' and 'stopped' or 'reversed' in a phylogenetic context.
Re: Wallace's Line, then you get into biogeography, and maybe how particular Earth regions might 'map' onto the Paph part of the slipper tree. i.e., using geographical areas as characteristics. If one tries this on the tree of Cox et al., one does not get a single most-parsimonious solution for all slippers since Old World / New World shifts back and forth. But within Paph, it becomes clear (from parsimony) from the tree nodes that mainland SE Asia is 'primitive', followed by movement out into insular SE Asia.
If you don't like parsimony, then I suggest you read the literature that supports its use as a scientific criterion for the basis of argumentation (comparison) of the robustness of hypotheses . E.g., try http://en.wikipedia.org/wiki/Ockham%27s_razor
Of course, use of parsimony inference does not mean that evolution proceeded parsimoniously! It simply means that one does not make extra assumptions that are not necessary to explain given data at hand. If you choose a hypothesis that is less than most-parsimonious, you do so by 'waving your hands in the air', and take a greater risk of hypothesis refutation.
Hope this helps,
That is an extremely interesting statement for someone claiming to be a scientist.
I think that this statement is in accord with most post-positivist science methodology. The general idea is that scientists can provide support for certain theories, and dis-prove alternative theories, but not prove theories to be true. This is a well accepted position within science and the philosophy of science.
- Matthew Gore
we are not talking about philosophy of science here. We are talking about a group of people claiming that they can decide on the phylogeny of organisms (in our case: plants) by looking at a very limited part of the genome. If those people (as Victor has so clearly confirmed) are not willing to explain their materials and methods and are not willing to discuss the sense or nonsense of their method, then, they have nothing to do with any scientific approach which they are supposed to have learned in their first semester of university. Fact is that not I, but Victor and his colleagues claim that they have the method of choice. And you are all willing just to take their word for it?
I wonder what they are afraid of. Fact also is, that more and more often, they must review their interpretation.
I, for my part, have failed 3 students last term for making the kind of statements Victor and his colleagues make. And I will keep doing so as long as I teach university.
Don't forget that it is they who say that Laelia purpurate is a Sophronitis, etc. etc,
If they were to be followed, anyone could claim tomorrow that paphiopedilums have been derived from cattleyas. If that is the sense of this forum, then I must reflect on whether I am willing to waste any more time on this.
Guido J. Braem
I agree that sceintists are responsible for explaining and supporting their conclusions, and I am making no claim at all regarding the validity of Victor Albert's work.
In response to this statement, you have called into question the requirements of justification for his claims, making this an epistemic issue. As such, it is proper to answer the question from the standpoint of Philosophy of Science.
As I say, this only places different requirements on what Dr? Albert must provide as justification. Science does not require that he provide proof (in the logical or geometrical sense) for his proposition. Obviously, this doesn't mean that his proposition requires no justification... and I don't know whether he has provided what is required or not, as I haven't read his publications.
- Matthew Gore
I am svery sorry to differ.
All I have done is to ask Victor Albert to tell us what methods and materials he uses and to explain to us how he comes to his results and how he comes to his interpretations. That is nothing to do with any philosophy of science but has to do with the verification of the applicability of his methods and the meaning of his interpretation. Any claim in science is to be verified on those bases.
If Victor Albert refuses to do that, the question that should be asked is: "What has ge got to hide?"
Well, I'm glad we took a break with this one. Never hid a thing, will still be happy to chat, but will not engage in phantasmagoric argumentation! :rollhappy:
Welcome back! We've missed you.
Wow, somebody pulled out Mr. Peabody and his Wayback Machine for this one
But it's timely again, with all the new hybrid names being posted, and all of the changes to Cattleya and Sopronitis, and the decimation of Laelia.
Separate names with a comma.