Talk:Vestigial structures

Article deletion by user:Conservative in 3....2...1.... --Gulik2 14:26, 10 May 2007 (EDT)

Get a lot of citations, and quick. He can't delete an article with 15 citations. --Hojimachong^talk 14:26, 10 May 2007 (EDT)

Really? He blocked me for two weeks because (I think) I cited papers by Maxwell and Einstein to support my claim that light in a vacuum has a constant speed. He didn't actually say why at the time though. - Suricou

Lol:) This should be under developmental Biology and Evolution Categories. Go to pubmed and you can find plenty of articles that deal with this topic, hard evidence.--TimS 14:40, 10 May 2007 (EDT)

I just made the article sound a little more encyclopedic and added a reference. GodWarrior 16:23, 23 May 2007 (EDT)

Overall the changes are good, but the removal of the point on natural selection is puzzling. Learn together 18:14, 23 May 2007 (EDT)

Sorry, I just felt it wasn't very encyclopedic the way it was worded especially the part in the form of the question. Also, it seems consistent with the Natural Selection that vestigial structures could be "in the process" of being phased out. GodWarrior 18:26, 23 May 2007 (EDT)

Part of the 'two-edged sword' of natural selection is that it should weed out inefficiencies as an outgoing occurrence and if it's not doing so, then they aren't inefficiencies. Giving it an open ended "in the process" can be fine if we're talking about short time periods on an evolutionary scale, but when we're talking about tens of millions of years then there is a benefit or a neutrality to the structure that by definition says it is not useless. Learn together 19:45, 23 May 2007 (EDT)

If the structure is neutral from the point of reproductive and general fitness, then there is no selective pressure for it to be eliminated and it could potentially persist until random mutations eliminate or change it. GodWarrior 21:06, 23 May 2007 (EDT)

Structures with any meaningful size to them are never neutral if they perform no positive function. The body has to use resources to sustain them as part of the overall living organism. Learn together 22:31, 24 May 2007 (EDT)

That is true. However, many vestigial structures are greatly reduced in size such as the coccyx and appendix such that their impact on resource usage is negligible in comparison to other factors, even random ones. This makes their impact on reproductive fitness essentially neutral. Consider the appendix, a thin piece of tissue about four inches long, the resources that go in to creating and maintaining such a structure are not likely to have any effect on the number of successful matings a person has. Also consider that the genes responsible for making a vestigial structure may be closely linked genetically (or even share some of the same genes) with the genes that are responsible for making other structures that are still required in humans. This could make it very difficult to remove the genes responsible for the vestigial structure without disturbing those that are still needed. GodWarrior 09:50, 25 May 2007 (EDT)

If it takes energy and there is a gain in efficiency to be had by its removal, then that should occur unless perhaps the structure is microscopic in size. Based upon your assertion that it should have no affect, then there would likewise be no reason for vestigial structures to become smaller in size, and yet evolutionary theory says that is exactly what has occurred. I should probably also point out that the article as written misses much of current evolutionary thought. While initial beliefs by evolutionists mirrored more of the idea that vestigial structures were useless, that line of thought caused evolutionists to get egg on their face and it is now generally accepted that vestigial structures can provided secondary or alternative positive influences that benefit the species. Vestigial structures are now viewed as those that have lost their original purpose, but without any claim being made to their uselessness. Learn together 03:13, 28 May 2007 (EDT)

I think Learn together makes a good point about the resources required, and the response to that just goes to show how flexible evolution is: if evolution gets rid of something, it is because it was a disadvantage, but if it doesn't get rid of something, it must be because it wasn't that much of a disadvantage. It's a tautology, really (how do you know if it was a disadvantage? By whether or not evolution got rid if it), and by being so flexible that it explains everything, it really explains nothing, but is a "just-so" story. Philip J. Rayment 08:00, 28 May 2007 (EDT)

It is not that natural selection won't ever get rid of things that don't provide an advantage, it's just that it might take a while. You can't expect these things to happen in one generation. Also, keep in mind that sometimes changes happen that are clearly not advantageous due to purely to chance, founder effects, etc. For example, humans have a defective gene for the enzyme that makes vitamin C, while all mammals, except apes and guinea pigs, have functional copies of the gene. This is why humans are susceptible to scurvy while other mammals are not and why we must take in vitamin C in our diet. Looking at the current iterations of animals, especially humans, is probably not the best way to study evolution because the influence of humans and modern society has changed the game so much. Evolution is best studied over millions of years. GodWarrior 09:57, 29 May 2007 (EDT)

Article name

I've normally heard of these things as vestigial organs, not structures. I'd vote to change the page name accordingly. Any objections? Philip J. Rayment 08:00, 28 May 2007 (EDT)

Actually, Vestigial organs already exists. So any objections to the content of this one replacing the content of the other? Philip J. Rayment 08:04, 28 May 2007 (EDT)

I have no objection. Learn together 14:24, 28 May 2007 (EDT)

Human appendix

GodWarrior wrote in his last edit comment: "Read references before adding them please, evidence in them is far from conclusive. The absolute nature of the statement is still far from justified.)". I wonder if he has read the references. I'd like to know what is inconclusive about these:

• "The mucosa and submucosa of the appendix are dominated by lymphoid nodules, and its primary function is as an organ of the lymphatic system."
• "The appendix, in conjunction with other parts of the body which also contain cells called B-lymphocytes, manufactures several types of antibodies"
• "Although it used to be believed that the appendix had no function and was an evolutionary relic, this is no longer thought to be true. Its greatest importance is the immunological function it provides in the developing embryo, but it continues to function even in the adult … . The function of the appendix appears to be to expose circulating immune cells to antigens from the bacteria and other organisms living in your gut. That helps your immune system to tell friend from foe and stops it from launching damaging attacks on bacteria that happily co-exist with you."
• "it is now known to play a role in fetal immunity and in young adults. During the early years of development, the appendix functions as a “lymphoid organ”?, assisting with the maturation of B lymphocytes (a type of white blood cell) and in the production of immunoglobulin A antibodies [both of which help fight invading germs]. In addition, at around the 11th week of fetal development, endocrine (hormone-producing) cells appear in the appendix. These cells produce peptide hormones that control various biological mechanisms."

The second one can be read as being inconclusive, but was said in direct reply to a surgeon's claim that "it no longer serves a purpose in humans", and was preceded with the comment, "Your surgeon was a little out of date". In case it needs to be said, only one of these quotes is from a creationist.

Philip J. Rayment 23:12, 29 May 2007 (EDT)

I'm talking about actual hard data. What I meant was that if you cite a POV source such as the Journal of Creation, then you have to make sure that their NPOV references actually verify their arguments. None of the peer-reviewed papers (the only ones that really matter) cited in those articles are even accessible. It is therefore impossible to check if they actually agree with the statements attributed to them. Using medline, pubmed, and thomson ISI I was unable to even get an abstract from any of them. This is highly unusual as those sources usually have any article I am trying to find. Also, just because one source draws that conclusion does not meant that it is irrefutable. If there is conflicting evidence on a topic it is inappropriate to make a definitive statement in an encyclopedia such as "The human appendix has a role in early development." It is fine to cite summary pages like you have done because it makes it easier for the reader to learn more about the topic, but please check the veracity of them before you do so. GodWarrior 07:35, 30 May 2007 (EDT)

This sounds very much like a case of demanding a higher standard than you would normally expect of yourself.

The Journal of Creation is no more POV than other sources, most of which presume an evolutionary worldview.

Your Talk.Origins source spends very little of it's page actually discussing whether or not the appendix has a use. The bits that do have the following references:

• Judge and Lichtenstein 2001: The link provides no summary, but the title suggests that it does: "Is the appendix a vestigial organ? Its role in ulcerative colitis." (my emphasis)
• Dasso et al. 2000: The linked summary includes, "If the human appendix functions as a primary lymphoid organ, it may occur during the first few months of age when the GC T-cell density is low". That indicates that they didn't find a use in the areas they looked, not that there is no evidence at all, as Talk.Origins claims.

Apart from an older reference that predates some of the Journal of Creation's sources, that seems to be it. That's hardly a convincing argument that there is no certain evidence in the face of unequivocal claims that there is evidence. And surely sources that know of evidence trump those that don't know of evidence?

Philip J. Rayment 09:31, 30 May 2007 (EDT)

I am a little confused as to what exactly you're arguing here...the page I cited has copious references most of which are accessible through pubmed. In some cases it even provides a link for you! I am not going to count them all but it looks like over 60 peer reviewed papers. Your sources cited about 4, none of which I could find despite my best efforts. Are you seriously calling the NEJM as POV as the Journal of Creation? It's one of the most widely respected journals in the world. On the ulcerative collitis issue, the proposed role of the appendix in that disease is that it causes it! I don't know about you, but I think causing a disease does not constitute evidence that the organ is not vestigial. If you are in doubt feel free to read the NEJM paper on the same topic (its just above the one you cherry-picked). The page I cited is correct to claim that the Dasso paper provided no evidence for an immunological function for the appendix, it looked for one and was unable to find it! They didn't say that the authors did an exhaustive search of every possible time and place that the appendix could have a role and conclusively determined that it didn't have one. There is a big difference. Please also keep in mind that the statement that my citation is attached to is "Examples of structures claimed to be vestigial include, but are not limited to, the human appendix..." I did not attach this to a definitive statement like you did. As for your last statement: are we looking at the same page? Do you see those dozens of blue hyperlinks? Those are all references! Frankly, I think the page I cited does a much better job providing evidence for non-vestigiality than the ones you cited did. Just look at the section of the references titled "possible functions." There are 10 peer-reviewed sources there. Before you do that however, I would recommend taking a look at some of the references under the "Congenital Absence of the Appendix" section. We just might settle this argument after you do that...unless you can tell me how someone born without a non-vestigial organ can survive with no ill effects? GodWarrior 10:20, 30 May 2007 (EDT)