Branchial arches or biomechanical flexion folds?

I think the point of calling them biomechanical folds is that such folding occurs no matter where the flexion side is, and so evos took a superficial look ar folds and asserted they were gills, or gill slits, or perhaps gill pouches, which they are not.WK offers, from what I have read on this forum, one study that shows some scant evidence indicating genes in this region being the same or similar to genes in the neck region for gills. Imo, this is a large stretch and attempt to revive the old icon of gill slits.In other words, the superficial appearance argument being shot down, the same argument is trying to be advanced on molecular studies.The problem is, in reference to the appearance of the folds, that not all embryos of vertibrates show such folds.Imo, if evos want to make this case, they need to do a couple of things.1. First show whether or not the genes they link to gill slits are present in other species, especially along the proposed evolutionary path, and to what degree those genes are present, and how the combinations of gene expressions can differ. Just pointing out there is a gene for the thymus in humans that is the same for the gills in fish, is not sufficient. There is a need for a more comprehensive analysis, and how this particular theory can be falsified.2. Second, to what degrees to common genes found for other areas of development homologous. Let's say the gene for developing fish scales is found in the genes for expressing the human liver. That would mean that finding similar genes does not necessarily relate to similar function and thus undercuts the case for homology.3. Are the other genes for developing the head and neck for humans, and the gills for fish homologous? For example, are there genes for gill slits in fish that are found for the reproductive organs or something in humans, and vice versa. Unless one can safely show the levels of correspondence in genes in this manner with function, then it seems a bit of a stretch to say, look here, we've got a gene in for the fish gills that's a gene for human neck organs.4. Evos need to recognize that the earlier claim of flexion folds is not refuted if there is a discovery of genetic homologies. It's apples and oranges.The folds are just that, folds, not gill pouches. Nothing can really change that. You bend the body, and you will see folds.

I've to go and you responded to this late at night so all I can do is post an abbreviated response.If you look say at Richardson's 1997 study dealing with Haeckel and conserved stages, there are a lot of pics in there showing embryos, and what you see is a sort of unfolding effect, and to the degree of infolding, you see differences in Pharyngeal arches, and a fairly wide degree of differences.First, you see that not all vertibrates have the same arches, and some appear to have significantly differing structures. Secondly, regardless of molecular markers, the folds appear due to the way the embryo unfolds. In other words, the folds are just that, folds due to the compression of the embryo.To say, well, the way the embryo unfolds is caused by genes is silly. Of course, the way the embryo unfolds is caused by genes, but that doesn't change the fact the folds are biomechanical flexion folds. Their similarity in appearance in respect to being bunched up together, making a flexion fold, is entirely due to the side effect of the biomechanical unfolding development of the embryo.Arguing there are molecular markers is a separate issue. It's really apples and oranges here. The 2 ideas are not mutually exclusive of one another. I don't know. How many species are there that should relate to this study? I would expect a sizeable percentage before a solid claim can be relied on, at least 100 or more as a start. But finding a few molecular markers does not answer the question if molecular markers line up in this way. For example, what other markers are there? Are there similar markers/genes that function for the development of different areas of the body, such as the liver or somewhere, that thus connect 2 non-homologous structures? Can genetic markers appear between 2 different functions? If so, making the claim of similar markers for gills and the parathyroid is less persuasive since similar markers can occur for non-homologous structures.You guys say, look, these markers relate to salt intake or some such, and so does this gene found in the parathyroid. OK, that's a start. It's not that conclusive yet. What if we find genes that are the same but do different things for different parts of the body? Does that throw out the first premise?In other words, is this a rule or something? That homologous structures will all have homologous genes, and no genes that don't appear homologous?And if that's true, is it possible the genes are just related due to similar function, and so represent no more of an argument for evolution that similar design?This message has been edited by randman, 12-13-2005 03:10 AM

This is true. There is a mechanical caused fold on the flexion side of the embryo. Neither of these 2 points negates in the slightest the point made about the mechanical cause of the fold. Certainly, genes control the process of development, and as such, indirectly cause the mechanical folds, but the mechanical folds are still just that.In other words, the molecular argument is a separate issue, one worth discussing, but hardly negating the fact that these are biomechanical flexion folds determined by the unfolding nature of the developing embryo, as can be seen if one looks at a good number of embryos.

I don't see whether genes control development is an issue. I will cede the point that genes do control development although I am surprised anyone thought otherwise.But all that shows is that genes are indirectly involved in creating the form, as the folds are indeed the result of the way the anatomy unfolds with an embryo, sort of like a balled up something unfolding out. So of course, there are folds, but that is due to the way the body grows mechanically.

So "unfolding" is poor terminology. The same point remains. It is still a biomechanical flexion fold. That's what it is.I think you are missing the forest here for the trees. The fact genes direct the way the embryo grows is true, and therefore indirectly causes the folds, but the folds are the result of the bend, the growing out of the head and neck. As you show in your pictures, there is a bending occurring. The bending is a biomechanical process.As an aside, caterpillars have folds too. Are they "gill pouches"?

So. That being the case, the arguments should be less dogmatically. Instead of bogus statements asserting homology as a well-nigh proven fact, there should be caution from inferring too much from one gene study or even a few. The hypothesis is just fine to make, but to claim a substantial level of evidence without more details is leaping to a conclusion, which is typical of evos.Yea, it's a lot of work. It's a lot of work to do most things in life. Maybe in 10-15 years, we'll have a more data and can make a more conclusive assertion. Wrong. It's being divorced from reality to demand something as basically true (in layman's terms) without sufficient data, just because it's presently too hard to obtain that data. The reality is we won't know until we have the data. So we have to give it time. Could be a very long time even.

If you want to present links or quotes from his book, that would be fine. I think what he says about biomechanical folds from what I have read, and don't have his whole book, is pretty clear. The way I am reading this is that there is a process and rate of growth for the embryo, biomechanically, meaning just how the tissue is connected and is growing, that causes the folds. If we think substitute "mechanically" to mean biomechanically, it's a little easier, it seems to me. There is a mechanical process for the head and neck region growing out of the heart/chest area, which I know is imprecise and more a layman's paraphrasing, but as this process of growth occurs, there are folds as a result of the mechanical process.It may be, as you suggest, that he does not recognize that the mechanical process is caused by genes. I have a hard time believing that because even a student knows genes control the growth process, but maybe I am missing something here?Regardless, the fact genes cause the process does not change the fact the process causes the folds.

I don't have his book. The quote makes a fairly obvious point; that these are biomechanical folds, and indeed one can view embryos and see that.You guys claim homology based on molecular data, incomplete data, but still data. So make that claim.The error imo is trying to resurrect the outward appearance of the folds as evidence based on the molecular data. Let me put it this way. Let's suppose no folds exist at all. Would you not still claim homology all the same based on the molecular data?The folds due to "the embryo's head growing around the heart to which the neural tube is anchored biophysically via tension-bearing blood vessels" seems fairly straightforward as a proposition. There is an appearance of folds due to the growth pattern.One reason I mentioned caterpillars as an aside is because we see folds there as well due to the way the caterpillar grows, to illustrate a point.

Not really. Another argument is that evos are making molecular claims on insufficient data in order to resurrect the ole human gill slits myth.But either way, the folds are still biomechanical folds. That's what they are.

That's because my experience with evo claims is they are usually based on overstatements, hoaxes, and unobserved dogma. Asking for sufficient data should not be considered something loathsome, but merely following some semblance of evidentiary logic.

Except that hypothesis was a hoax, based on faulty and manufactured evidence. The Biogenetic Law was wrong, but evos bought it hook, line, and sinker and have allowed it to color their perception of data. Even the lesser claim of a single phylotypic stage is wrong, and the claims of pharyngeal pouches has always been grossly exagerrated.So I think a more prudent approach is, considering the history of evo claims in this area, is to take any new claims of homology with a grain of salt, and demand sufficient evidence so we are not led down the prior paths of believing and teaching a lie, as we did for 125 years. From what I can tell, your arguments consist of claiming that because the folds are produced by a process controlled by genes, that the biomechanical folds description is inaccurate. If that is not your argument, please clarify.I concede that genes control the process, but don't see it as germane since the process controls the folds appearing.

I did address the data. The questions I raised are necessary to know if the data indicates what you claim it does. Just because some genes are expressed regulating salt intake for the parathyroid and gills is insufficient to resurrect the myth of recapitulation and insist these folds are not what they actually are, biomechanical flexion folds, and moreover, molecular data does not change that, even if it did indicate homology.

Yaro, we could that sometime except you are probably unaware of what my beliefs are, I suspect, based on your posts, and the next debate is with nuggins.Basically, "my creationist beliefs" primarily center around what data says in respect to evo claims. I do not hold to any one model of creationism or Intelligent Design.There are a few ideas I believe and hold to, some in respect to quantum mechanics, the fact of a deeper reality within the universe, that causal affects may work beyond a linear time-line framework, etc,...Most of my beliefs in respect to evolution come from examining the claims of evos and finding them lacking in substance.

Your question illustrates the fundamental difference between evos and myself. I don't have a need for there to be an explanation. I think it's a worthy pursuit, but an answer of we are still working on the problem is sufficient. Making up false data, overstating claims, and all the rest is not necessary and worse, it is not valid science.What I do know is a lot of evo claims have been false or overstated, and imo, some evidence strongly contradicts evolutionary theory. So imo, a good start is to go back to the drawing board, which is one reason ID theory appeals to me. It seems to want to make theories based only on empirical observation rather than trying to make the observations fit the theory, as I think evos do.

They work in what way?
Did the Biogenetic Law work? No.
Is the fossil record replete with species to species transitions? No.
Are mutations random as evos assert? We have no idea.
Evolutionary theory no more "works" than ID or creationism or anything. Recapitulation was based on false data. Claiming mutations are random is based on no real data at all. Claiming the fossil record shows evolution is false data, imo. There is no evolution seen in the fossil record. You have to "interpret" the data to include non-observables to make it work, and you have no explanation for the non-observed data not being there.Claiming peppered moths is "evolution in action" is misleading if not outright false, and on and on. Just about every evo claim is colored with overstatement and presumption.