[_ Old Earth _] If humans evolved from apes, where is our tail?

[Crying Rock]

"Vestigial" means "no longer having the original function." The coccyx is no longer movable, so it's no longer useful as an organ of balance, which is what it was in primitive primates.

Provide direct evidence that the human coccyx has anything to with primitive primates' organs of balance. Please, no conjecture. I'm not interested in in philosophical discussion.

 

[Barbarian]

Provide direct evidence that the human coccyx has anything to with primitive primates' organs of balance.

The same tissue in utero forms the tail we see in humans and other primates. The same vertebrae, nerves, muscles, etc. Later, the coccyx becomes relatively smaller, and the vertebrae fuse, and become completely nonfunctional. The muscles sometimes disappear, and sometimes are retained, but they no longer work because the fused vertebrae no longer can move.

And sometimes the genes that mediate this reduction don't work. And then, the tail actually develops. And can move. And are enervated by the same spinal nerves that function for each vertebra in other primates.

Please, no conjecture.

You would need a huge resistance to reality to consider that to be "conjecture." Only people with a very strong philosophical bias would deny that kind of evidence.

 

[lordkalvan]

This is only a partial answer to only one of my questions. I do not see how a tumour at the base of the coccyx is evidence either way whether or not the coccyx is vestigial or non-vestigial.

What leads you to suppose that there is difficulty distinguishing between a sacrococcygeal teratoma - which is actually one of the most common tumours amongst new-borns, occurring in around 1 out of every 35.000-40,000 births - and, for example individuals born with a 'tail that comes complete with fully developed vertebrae, muscles, and other features of animal tails'? I would be interested in why you think a fluid-filled cyst or solid mass can be misunderstood for the vertebrae and muscles of a tail. Perhaps you can provide some examples of where this has occurred? Please don't overlook my other questions in the process.

I think the burden is on you to show good evidence of a vestigial tail. So far you've failed. Sacrococcygeal teratomas have come complete with teeth and toenails. Evidence of the Second Law as it applies to information. Muscles of a tail? Prove it. These muscles that you imagine have no function in humans? If they do have a function, then they are not vestigial, and any other interpretation is conjecture.

May I remind you that I was responding initially to that part of your post as follows:

Prove it: precisely that a human coccyx is vestigial. I want observational evidence. Not conjecture.

I asked you to clarify what exactly you meant, to which your only response was to post a largely irrelevant demand to 'prove' that in some way vestigiality is not confused with a cancerous growth. I rather think it is on your shoulders to show how such a feature could be confused with vestigial aspects of the coccyx. There seems to be nothing in the available medical information online that suggests that sacroccygeal tetraomas in any way resemble those 'human tails' that you have been referred to, that contain structures that equate to 'fully developed vertebrae, muscles, and other features of animal tails' that quite clearly are not themselves cancerous.

You have shifted from demanding 'proof' that the coccyx does not represent a vestigial feature in humans to demanding 'evidence' of a vestigial tail. You have failed to demonstrate that the tumours you refer to have been mistaken for 'human tails', you assert that muscles that exist in these 'human tails' are imaginary and then suppose that if they do exist they cannot be vestigial. May I point out that it is the coccyx itself that you were interested in determining the vestigiality or otherwise thereof and that these 'human tails' are indicators of a lost function of the coccyx, i.e. of its vestigial aspects.

However, as you have still responded to none of the questions I asked in the first place, defining no parameters at all by which it might be determined what you would or would not accept as persuasive evidence, it strikes me that you are set on denying any evidence that might be presented to you at all. You appear to define evidence as conjectural simply because it contradicts your own opinion.

Plus with Barbarian said.

 

[Crying Rock]

Provide direct evidence that the human coccyx has anything to with primitive primates' organs of balance.

the coccyx becomes relatively smaller, and the vertebrae fuse, and become completely nonfunctional. The muscles sometimes disappear, and sometimes are retained, but they no longer work because the fused vertebrae no longer can move.

I'm not following you:


"...the coccyx... not entirely useless;[3] it is an important attachment for various muscles, tendons and ligaments  which makes it necessary for physicians and patients to pay special attention to these attachments when considering surgical removal of the coccyx.[1] Additionally, it is also part of the weight-bearing tripod structure which act as a support for a sitting person. When a person sits leaning forward, the ischial tuberosities and inferior rami of the ischium take most of the weight, but as the sitting person leans backward, more weight is transferred to the coccyx.[1]

The anterior side of the coccyx serves for the attachment of a group of muscles important for many functions of the pelvic floor (i.e. defecation, continence, etc): The levator ani muscle, which include coccygeus, iliococcygeus, and pubococcygeus. Through the anococcygeal raphé, the coccyx supports the position of the anus. Attached to the posterior side is gluteus maximus which extend the thigh during ambulation.[1]

Many important ligaments attach to the coccyx: The anterior and posterior sacrococcygeal ligaments are the continuations of the anterior and posterior longitudinal ligaments that stretches along the entire spine.[1] Additionally, the lateral sacrococcygeal ligaments complete the foramina for the last sacral nerve.[4] And, lastly, some fibers of the sacrospinous and sacrotuberous ligaments (arising from the spine of the ischium and the ischial tuberosity respectively) also attach to the coccyx.[1]..."

http://en.wikipedia.org/wiki/Coccyx

Edit postReport this postReply with quoteRe: If humans evolved from apes, where is our tail?
by Crying Rock on Sun Jul 12, 2009 7:12 pm

"Vestigial" means "no longer having the original function." The coccyx is no longer movable, so it's no longer useful as an organ of balance, which is what it was in primitive primates.

You've failed to provide direct evidence that the human coccyx has anything to with primitive primates' organs of balance. Only conjecture.

 

[Crying Rock]

LK quoted:

You have shifted from demanding 'proof' that the coccyx does not represent a vestigial feature in humans to demanding 'evidence' of a vestigial tail. You have failed to demonstrate that the tumours you refer to have been mistaken for 'human tails', you assert that muscles that exist in these 'human tails' are imaginary and then suppose that if they do exist they cannot be vestigial. May I point out that it is the coccyx itself that you were interested in determining the vestigiality or otherwise thereof and that these 'human tails' are indicators of a lost function of the coccyx, i.e. of its vestigial aspects.

Do you claim the coccyx is the remnant of a vestigial tail? Do you claim the fleshy mutations that protrude from the spinal column are proof of that humans once had tails?

If so, then all I've asked you to do is provide direct evidence for these claims. If the claims are true, then providing direct evidence should be quite easy. So far you've failed.

CR quoted:

"...the coccyx... not entirely useless;[3] it is an important attachment for various muscles, tendons and ligaments  which makes it necessary for physicians and patients to pay special attention to these attachments when considering surgical removal of the coccyx.[1] Additionally, it is also part of the weight-bearing tripod structure which act as a support for a sitting person. When a person sits leaning forward, the ischial tuberosities and inferior rami of the ischium take most of the weight, but as the sitting person leans backward, more weight is transferred to the coccyx.[1]

The anterior side of the coccyx serves for the attachment of a group of muscles important for many functions of the pelvic floor (i.e. defecation, continence, etc): The levator ani muscle, which include coccygeus, iliococcygeus, and pubococcygeus. Through the anococcygeal raphé, the coccyx supports the position of the anus. Attached to the posterior side is gluteus maximus which extend the thigh during ambulation.[1]

Many important ligaments attach to the coccyx: The anterior and posterior sacrococcygeal ligaments are the continuations of the anterior and posterior longitudinal ligaments that stretches along the entire spine.[1] Additionally, the lateral sacrococcygeal ligaments complete the foramina for the last sacral nerve.[4] And, lastly, some fibers of the sacrospinous and sacrotuberous ligaments (arising from the spine of the ischium and the ischial tuberosity respectively) also attach to the coccyx.[1]..."

http://en.wikipedia.org/wiki/Coccyx

"...Infrequently, a child is born with a "soft tail", which contains no vertebrae, but only blood vessels, muscles...Some of these tails may in fact be sacrococcygeal teratomas..."


"...A man named Chandre Oram, who lives in West Bengal, a state in India, is famous because of his 13-inch (330 mm) tail. It is not believed to be a true tail, however, but rather a case of spina bifida..."


http://en.wikipedia.org/wiki/Tail

"...Sacrococcygeal teratoma (SCT) is a teratoma (a kind of tumor) located at the base of the coccyx (tailbone)..."

http://en.wikipedia.org/wiki/Sacrococcygeal_teratoma

 

[Barbarian]

"...the coccyx... not entirely useless;[3] it is an important attachment for various muscles, tendons and ligaments  which makes it necessary for physicians and patients to pay special attention to these attachments when considering surgical removal of the coccyx.[1] Additionally, it is also part of the weight-bearing tripod structure which act as a support for a sitting person. When a person sits leaning forward, the ischial tuberosities and inferior rami of the ischium take most of the weight, but as the sitting person leans backward, more weight is transferred to the coccyx.[1]

The anterior side of the coccyx serves for the attachment of a group of muscles important for many functions of the pelvic floor (i.e. defecation, continence, etc): The levator ani muscle, which include coccygeus, iliococcygeus, and pubococcygeus. Through the anococcygeal raphé, the coccyx supports the position of the anus. Attached to the posterior side is gluteus maximus which extend the thigh during ambulation.[1]

Many important ligaments attach to the coccyx: The anterior and posterior sacrococcygeal ligaments are the continuations of the anterior and posterior longitudinal ligaments that stretches along the entire spine.[1] Additionally, the lateral sacrococcygeal ligaments complete the foramina for the last sacral nerve.[4] And, lastly, some fibers of the sacrospinous and sacrotuberous ligaments (arising from the spine of the ischium and the ischial tuberosity respectively) also attach to the coccyx.[1]..."

http://en.wikipedia.org/wiki/Coccyx

Pretty easy to refute. Coccygeal agenesis is a common condition in humans, one that is normally completely asymptomatic. If the coccyx is functional, why does it's absence have no consequences at all?

Significant neurological deficits are associated with the high sacral malformations, but isolated coccygeal agenesis is usually asymptomatic.
http://journals.lww.com/neurosurgery/Ab ... ord.9.aspx

You might as well argue that the appendix has a function, since it blocks what would otherwise be a hole in the bowel.

Barbarian observes:
"Vestigial" means "no longer having the original function." The coccyx is no longer movable, so it's no longer useful as an organ of balance, which is what it was in primitive primates.

You've failed to provide direct evidence that the human coccyx has anything to with primitive primates' organs of balance.

Other than embyrological, neurological, anatomical, and other data, including rare cases of true tail in humans, where the vertebrae develop in the same manner and features as primates with short tails.

It appears "conjecture" is your private term for "overwhelming evidence."

 

[Crying Rock]

"...the coccyx... not entirely useless;[3] it is an important attachment for various muscles, tendons and ligaments  which makes it necessary for physicians and patients to pay special attention to these attachments when considering surgical removal of the coccyx.[1] Additionally, it is also part of the weight-bearing tripod structure which act as a support for a sitting person. When a person sits leaning forward, the ischial tuberosities and inferior rami of the ischium take most of the weight, but as the sitting person leans backward, more weight is transferred to the coccyx.[1]

The anterior side of the coccyx serves for the attachment of a group of muscles important for many functions of the pelvic floor (i.e. defecation, continence, etc): The levator ani muscle, which include coccygeus, iliococcygeus, and pubococcygeus. Through the anococcygeal raphé, the coccyx supports the position of the anus. Attached to the posterior side is gluteus maximus which extend the thigh during ambulation.[1]

Many important ligaments attach to the coccyx: The anterior and posterior sacrococcygeal ligaments are the continuations of the anterior and posterior longitudinal ligaments that stretches along the entire spine.[1] Additionally, the lateral sacrococcygeal ligaments complete the foramina for the last sacral nerve.[4] And, lastly, some fibers of the sacrospinous and sacrotuberous ligaments (arising from the spine of the ischium and the ischial tuberosity respectively) also attach to the coccyx.[1]..."

http://en.wikipedia.org/wiki/Coccyx

Pretty easy to refute. Coccygeal agenesis is a common condition in humans, one that is normally completely asymptomatic. If the coccyx is functional, why does it's absence have no consequences at all?

"...it is an important attachment for various muscles, tendons and ligaments  which makes it necessary for physicians and patients to pay special attention to these attachments when considering surgical removal of the coccyx..."

http://en.wikipedia.org/wiki/Coccyx

 

[coelacanth]

CR,

You list functions performed by the coccyx. How is its structure related to those functions? Please include an explanation for the need that an intelligent designer would have for the fusion of several small and separate bones in order to facilitate these functions, as well as the inclusion of seemingly unnecessary latent genes described by lordkalvan.

If you can’t find a peer-reviewed answer, conjecture is fine ;)

 

[Barbarian]

"...it is an important attachment for various muscles, tendons and ligaments  which makes it necessary for physicians and patients to pay special attention to these attachments when considering surgical removal of the coccyx..."

For the same reason a surgeon much take care with removal of the appendix. There are blood vessels, a connection to the large intestine, etc. But if either of these vestigial structures are missing, the individual usually never knows about it. This is playing to the same misconception that works when someone offers to pay to have them removed from any person who notes that they are vestigial.

How "important" can they be, if there are no consequences to not having one?

Significant neurological deficits are associated with the high sacral malformations, but isolated coccygeal agenesis is usually asymptomatic.

 

[Barbarian]

You list functions performed by the coccyx. How is its structure related to those functions?

It's not. When the coccyx is not present, these tissues attach farther up, to the sacrum.

 

[coelacanth]

I haven't found any specific quotes by Randolph Nesse about the coccyx, but his work on the science of Darwinian medicine would certainly be applicable here, to any who are familiar with his work.

 

[lordkalvan]

[Do you claim the coccyx is the remnant of a vestigial tail?

What is your understanding of what constitutes a 'vestigial tail'?

Do you claim the fleshy mutations that protrude from the spinal column are proof of that humans once had tails?

If so, then all I've asked you to do is provide direct evidence for these claims. If the claims are true, then providing direct evidence should be quite easy. So far you've failed.

And so far you've failed to provide parameters for your requests in terms of those questions I originally asked you and the supplementary questions I asked in an attempt to clarify your own understanding, i.e.-

What are your requirements for 'proof'?

What observational evidence would meet your demands?

How exactly do you define conjecture?

Perhaps you would care to 'prove' that the human coccyx is not vestigial?

Is it vestigial in other great apes?

What observational evidence supports your conclusions?

The tail is not a physiological attribute of humans and other great apes. The coccyx is evidence that an ancestral species had a fully functional tail. Tails in human babies that demonstrate all the aspects of 'real' tails support this conclusion; they are quite clearly not restricted to 'fleshy mutations' and you have not shown that they are nothing more than this. The tail in developing embryos also adds to confidence in this conclusion. This is not conjecture. Why do you regard it as such and the presentation of this evidence as 'failure'? You have also failed to show how sacrococcygeal teratomas might be confused with such structures or, for that matter, how sacrococcygeal teratomas bear on the subject at all. Is it your understanding that no animals at all show vestigial features, such as ostrich and emu wings and expressible tooth-genes in birds? What evidence supports your understanding?

 

[Crying Rock]

[Do you claim the coccyx is the remnant of a vestigial tail?

What is your understanding of what constitutes a 'vestigial tail'?

Do you claim the fleshy mutations that protrude from the spinal column are proof of that humans once had tails? If so, then all I've asked you to do is provide direct evidence for these claims. If the claims are true, then providing direct evidence should be quite easy. So far you've failed.

Jeez, I’ve been waiting (over a month now) for unequivocal evidence that fleshy mutations that protrude from human spinal columns are proof of that humans once had tails, and the even deeper issue: did humans evolve from apes.

 

[lordkalvan]

[quote="Crying Rock":4ulf7qlx][Do you claim the coccyx is the remnant of a vestigial tail?

What is your understanding of what constitutes a 'vestigial tail'?

Do you claim the fleshy mutations that protrude from the spinal column are proof of that humans once had tails? If so, then all I've asked you to do is provide direct evidence for these claims. If the claims are true, then providing direct evidence should be quite easy. So far you've failed.

Jeez, I’ve been waiting (over a month now) for unequivocal evidence that fleshy mutations that protrude from human spinal columns are proof of that humans once had tails, and the even deeper issue: did humans evolve from apes.[/quote:4ulf7qlx]
And I've been waiting a similar time for you to clarify what your understanding is in respect of certain aspects of this discussion, clarifications that you appear unwilling to give. What do you find unconvincing in the points already made that have been offered in response to your demands? I should perhaps point out also that I am addressing the conclusions that can be drawn from the weight of evidence available; if you want absolute proof you need to go somewhere else, as I'm fairly sure that nothing that could be put to you here would meet whatever criteria you have for determining what constitutes this.

 

[Barbarian]

Jeez, I’ve been waiting (over a month now) for unequivocal evidence that fleshy mutations that protrude from human spinal columns are proof of that humans once had tails, and the even deeper issue: did humans evolve from apes.

The literature makes a distinction between pseudotails and true tails in humans. True tails have bones, ligaments, muscles, etc, and are composed of tissues that would normally form the coccyx. The latter are genuine tails.

This doesn't illuminate anything about human/ape evolution, since apes also have vestigial tails, like humans.

 

[Kilomech]

This doesn't illuminate anything about human/ape evolution, since apes also have vestigial tails, like humans.

/Thread

 

[jasoncran]

break one's coccyx and find out how painful and out of balence you are at times, that will tell its function. My wife has broken it and the docs dont want to operate for fear damaging nearby nerves

 

[Barbarian]

Um, its function is to hurt you? BTW, coccigeal agenesis (people born without a coccyx) is normally completely asymptomatic and people usually never know they don't have one.

It's just an example of a vestigial organ that is also now functionless. Many vestigial organs are modified to some new use.

 

[jasoncran]

Um, its function is to hurt you? BTW, coccigeal agenesis (people born without a coccyx) is normally completely asymptomatic and people usually never know they don't have one.

It's just an example of a vestigial organ that is also now functionless. Many vestigial organs are modified to some new use.

it does affect you balences, it called the sacral 3, and 4 of the vertabrea, my wife was on a four wheeler and was thrown off an landed on the four wheeler right on the tail bone, in the x-ray you can see it almost broken off and cocked to the right.

Most martial arts also teach to strike that area in order to disrupt the equalibrlum usually a knee to it from behind then the followed by choke.

jason

 

[Barbarian]

i

t does affect you balences, it called the sacral 3, and 4 of the vertabrea, my wife was on a four wheeler and was thrown off an landed on the four wheeler right on the tail bone, in the x-ray you can see it almost broken off and cocked to the right.

No. The sacrum is above the coccyx. The upper part of the sacrum is important, because critical nerves run through the sacrum. In coccygeal agenesis, the lower part of the sacrum can also be absent without any symptoms.

Most martial arts also teach to strike that area in order to disrupt the equalibrlum usually a knee to it from behind then the followed by choke.

If it was critically important, it wouldn't be unnoticed when it was absent. But that's the case:
http://www.ajronline.org/cgi/reprint/115/3/611.pdf

Significant neurological deficits are associated with the high sacral malformations, but isolated coccygeal agenesis is usually asymptomatic.
journals.lww.com/.../Sacral_Agenesis_and_Caudal_Spinal_Cord.9.aspx