Precisely as I outlined, then? I refer you, again, to the following part of my previous post which discusses character reversals on a molecular level:
A quick look through the papers I have in my office and on Google Scholar gave at least two examples of supposedly advanced characters which have reversed to a previous state.
The first is the loss and subsequent gain of wings in stick insects, as proposed by Whiting, Bradler & Maxwell (2003; Nature 421, 264-267), and this is somewhat controversial (see Trueman, Pfeil, Kelchner, Yeates, 2004; Syst. Entomol. 29, 138-139, and Whiting & Whiting, 2004; Syst. Entomol. 29, 140-141). This study proposes that while the ancestor of Phasmatodea+sister groups was winged, the ancestor of Phasmatodea alone was wingless. Wings then reoccurred in some lineages at a later stage of the evolution of the modern stick insects.
The second is the reversal of direct development back to larval development in Plethodontid salamanders as proposed by Chippindale, Bonnett, Baldwin & Wiens (2004; Evolution 58, 2809-2822). I have not read this article more than the abstract and the phylogenetic trees, but will get back to this later.
In any case, reversal of the type you are after is commonplace at the genetic level, but becomes increasingly unlikely with increasing temporal distance between an ancestor and its descendant. However, if we assume (and the article does not address this) that a single change in the genes regulating wing development in the ancestor to stick insects, then a single change could very well be enough to reverse this pattern as well. This is unlikely, but certainly not impossible. Whiting & Whiting (2004) lists other proposed examples (references removed for brevity): "eyes in ostracods, ocelli in cave-crickets, wings in water striders, wings in male
Philotrypesis fig wasps, and other complex features in a wide variety of taxa", pointing to a review in "Developmental Plasticity and Evolution" by M. J. West-Eberhard (2003), Oxford University Press, New York. I don't own this volume, so if you want to look deeper into this, you will have to get it yourself. The prize on Amazon is £47.50:
http://www.amazon.co.uk/Development...2356/ref=sr_1_1?ie=UTF8&qid=1300712831&sr=8-1
Yes, you are. You are saying that the data does not support the conclusions I draw from the analyses of it, and as I use these conclusions to get funding and to earn a living, you are essentially accusing me of lying and deceiving -- perhaps unwittingly -- in order to get money, typically at the taxpayers' expense. That is fraud in my country.
Please don't feel that I am hurrying you. I, and also Sceptic Tank, am still asking the same questions as several days ago, and we are still patiently waiting for your answers. Hopefully, now that you have selected horses as your model taxon for supporting your assertions, we will not have to wait any further.
Please list some of these unsubstantiated claims again, so that we can know if these are actually unlikely to be true, or if you are just making unsubstantiated claims as if they are facts.
I have already several times addressed this issue by pointing out several characteristics about phylogenies which would make a beginner believe this to be the case. You have, as far as I remember, not yet responded to this, yet you persist in making the same claim. Are you of the opinion that the explanations I have offered for this misconception of yours are wrong? If so, tell me, and I will see if I can reformulate them.
"Appear to" does not equal "distinctly and umabiguously do". The flaw could be in your perception of what the mechanisms are.
Note: I have not had time to read the text you linked to, but I have printed it and may have time to do so tonight. Meanwhile, perhaps you could answer this question: Is it Davison's contention that all these structures are homologous to those in a non-protozoan organism? That is, is it his contention that,
e.g., the muscles are coded by the same genes in
Diplodinium as in,
e.g.,
C. elegans, or in us, for that matter?
If it is his contention, I would need evidence to back this up.
If it is not his contention, do you realise that his and your whole argument falls flat on its face? If one set of genes code for muscles in Metazoans and another code for "muscles" in Protozoans, this in no way implies that the genes that code for muscles (
sensu Metazoa) are present in the protozoa, nor that they necessarily were present in their common ancestor.
The same goes for this statement:
Does Davison mean that the "kind of placenta" present in
Peripatus is homologous to that of placental mammals? And, regardless of what he suggests, is it? Or is it a similar structure that performs the same task, but which has a different developmental and evolutionary origin?
Otherwise -- remember, I've only read your quotes so far -- this seems to suggest that he would also consider the fact that both grasshoppers and bats have wings evidence for bats having some characteristics of grasshoppers, despite these not being homologous structures in any way.
No, the claim you made was that all phylogenies contained groupings that would not be predicted by evolutionary theory:
Within the framework of phylogenetics, there is no other way to understand "groupings" than "clades", and there is no other way to understand "pattern of how species seem to be grouped together" than "nested clades". When asked to provide some evidence for this claim, you said:
Which can be interpreted only as that any given phylogenetic tree will contain such groupings. When prompted again to give evidence for your claim, and a method less biased to your detriment was proposed, you changed your claim to:
And then again changed the focus of the discussion from
your understanding of how the data supports
your claims, to how
our understanding of the data and the theory affects how the data supports
your claims. I will say it again: the data that supports your assertions will be the same whether you present it to experts or to novices.
I then proposed we look at the whole tree, and gave you a link to the most complete consensus tree of all life I know of, at which point you claimed again that you had substantiated your claim, but that the data you used somehow depends on
my understanding of the data and the theory.
We have not progressed an inch, and will not do so until you produce some data that supports you claim, which I suppose by now would be that in the overall patterns of the entire tree of life but not in any subsection of this tree there are groupings that would not be predicted by evolutionary theory. If you have listed some suggestions for such groupings, I have missed them, and would ask you to list them again. A handful will be enough, so it should not take too much of your time.
I will now go and do some lab work, and then return to your post where you start discussing horses.