Understanding through Discussion


Welcome! You are not logged in. [ Login ]
EvC Forum active members: 73 (8864 total)
Current session began: 
Page Loaded: 09-23-2018 8:21 PM
200 online now:
Coragyps, Tanypteryx (2 members, 198 visitors)
Chatting now:  Chat room empty
Newest Member: rldawnca
Post Volume:
Total: 838,846 Year: 13,669/29,783 Month: 1,115/1,576 Week: 56/271 Day: 56/39 Hour: 0/0


Thread  Details

Email This Thread
Newer Topic | Older Topic
  
Prev1234
5
Author Topic:   Recurrent Laryngeal Nerve: Part II
Dr Adequate
Member
Posts: 16035
Joined: 07-20-2006
Member Rating: 3.8


Message 61 of 75 (573113)
08-09-2010 9:27 PM
Reply to: Message 58 by ICdesign
08-09-2010 6:55 PM


I need to read up more on mutations. Honestly, it seems like Darwinists use a mutation like some magic wand to try and explain away all the problems with the theory.

Kinda like Newtonians and gravity.

I was trying to find out how the RLN originated. Not which organism had it first as much as how and why random mutations plus natural selection would have produced it. Evolution has no purpose so how and why did it migrate (according to you guys of course) to the organs it services and the larynx?

For that you'd have to consider the nature of development.

Consider, for example, the fact that ours skull are just the right sizes to hold our brains. Now, given that everyone's skull and brain come in different sizes ... is that just a huge coincidence, or is there something more subtle going on?

The gill evolving into a larynx?.... all you have is an inference and I just don't have that kind of faith.

All we have is evidence, and you just don't have that kind of knowledge.

I still think you are writing checks reality can't cash like giving evolution the power to make decisions ...

And you are, of course, totally, utterly, ludicrously, laughably wrong.

You really, really, really need to learn what the theory of evolution is, or how can you hope to discuss it.

... but I would rather do some more learning about mutations before saying more on that subject.

You might want to find out a little something about natural selection, too.

I don't really think your house of cards will crash on EvC but it is a fun thought ...

If fantasies about the demise of evolution were horses, then creationists would ride.


This message is a reply to:
 Message 58 by ICdesign, posted 08-09-2010 6:55 PM ICdesign has not yet responded

  
Taq
Member
Posts: 7557
Joined: 03-06-2009
Member Rating: 3.8


Message 62 of 75 (573212)
08-10-2010 12:34 PM
Reply to: Message 58 by ICdesign
08-09-2010 6:55 PM


I was trying to find out how the RLN originated. Not which organism had it first as much as how and why random mutations plus natural selection would have produced it.

It originated in one of our early vertebrate ancestors. In these species it was the nerve for the 6th gill slit as discussed in previous posts. As the gills evolved into the larynx and the larynx moved towards the head away from the torso the nerve went with it. The advantages that the larynx offered terrestrial vertebrates outweighed the design flaws that the RLN brought with it.

Also, don't you have problems with the ICR article? It states that God could not figure out a way to design vertebrate embryonic development so that the RLN did not loop under the aorta and subclavian artery. It suggests that God is not all powerful and all knowing.


This message is a reply to:
 Message 58 by ICdesign, posted 08-09-2010 6:55 PM ICdesign has responded

Replies to this message:
 Message 63 by ICdesign, posted 08-10-2010 8:19 PM Taq has not yet responded

  
ICdesign
Member (Idle past 2694 days)
Posts: 360
From: Phoenix Arizona USA
Joined: 03-10-2007


Message 63 of 75 (573319)
08-10-2010 8:19 PM
Reply to: Message 62 by Taq
08-10-2010 12:34 PM


Taq,

I sent you a private message.
Thanks for your respectful post.
IC


This message is a reply to:
 Message 62 by Taq, posted 08-10-2010 12:34 PM Taq has not yet responded

    
ICdesign
Member (Idle past 2694 days)
Posts: 360
From: Phoenix Arizona USA
Joined: 03-10-2007


Message 64 of 75 (574419)
08-15-2010 7:15 PM
Reply to: Message 41 by Huntard
08-08-2010 12:19 PM


Re: Doh....!!
Of course not. But if a random mutation would cause that to happen, leading to the death of the organism, the organism can't reproduce, and thus the mutation isn't propagated.

With all do respect to your working knowledge of RM/NS I am still stuck on this statement Sir.
What exactly is it that would "know" the organism would die and not reproduce? Is this not foreknowledge? Is this not thinking and reasoning?

With respect,
IC


This message is a reply to:
 Message 41 by Huntard, posted 08-08-2010 12:19 PM Huntard has responded

Replies to this message:
 Message 65 by Percy, posted 08-15-2010 8:41 PM ICdesign has not yet responded
 Message 66 by Dr Adequate, posted 08-15-2010 11:23 PM ICdesign has not yet responded
 Message 67 by Huntard, posted 08-16-2010 2:59 AM ICdesign has responded

    
Percy
Member
Posts: 17663
From: New Hampshire
Joined: 12-23-2000
Member Rating: 2.9


Message 65 of 75 (574431)
08-15-2010 8:41 PM
Reply to: Message 64 by ICdesign
08-15-2010 7:15 PM


Re: Doh....!!
ICDESIGN writes:

With all do respect to your working knowledge of RM/NS I am still stuck on this statement Sir.
What exactly is it that would "know" the organism would die and not reproduce? Is this not foreknowledge? Is this not thinking and reasoning?

I think it would help if we included the entire exchange that you're replying to. It's short:

Huntard writes:

ICDESIGN writes:

How would evolution know the organism would die if that nerve broke? Are you telling me evolution has reasoning ability?

Of course not. But if a random mutation would cause that to happen, leading to the death of the organism, the organism can't reproduce, and thus the mutation isn't propagated.

If a mutation caused the Laryngeal nerve to break during fetal development then the fetus would die. Evolution doesn't have to "know' anything. Evolution is just the name we give to the process of mutation and natural selection.

The term "natural selection" is actually well chosen because the selection process is entirely natural. Whether an organism is able to survive long enough to reproduce is determined by how well it competes in its environment. All it has to do is go about doing what it does naturally, and if at some point it is able to reproduce and contribute its genes to the next generation (including any mutations) then voila! It was selected!

--Percy


This message is a reply to:
 Message 64 by ICdesign, posted 08-15-2010 7:15 PM ICdesign has not yet responded

    
Dr Adequate
Member
Posts: 16035
Joined: 07-20-2006
Member Rating: 3.8


Message 66 of 75 (574449)
08-15-2010 11:23 PM
Reply to: Message 64 by ICdesign
08-15-2010 7:15 PM


Re: Doh....!!
What exactly is it that would "know" the organism would die and not reproduce?

Nothing whatsoever. But a fatal defect would cause the organism to die and not reproduce. Meaning that the mutation causing the defect would not be propagated through the gene pool.

Is this not foreknowledge? Is this not thinking and reasoning?

No. That's an organism with a fatal defect dying. Thinking, reasoning, and clairvoyance are not necessary for that to happen.

C'mon, this is basic stuff.


This message is a reply to:
 Message 64 by ICdesign, posted 08-15-2010 7:15 PM ICdesign has not yet responded

  
Huntard
Member (Idle past 192 days)
Posts: 2870
From: Limburg, The Netherlands
Joined: 09-02-2008


Message 67 of 75 (574461)
08-16-2010 2:59 AM
Reply to: Message 64 by ICdesign
08-15-2010 7:15 PM


Re: Doh....!!
ICDESIGN writes:

With all do respect to your working knowledge of RM/NS I am still stuck on this statement Sir.
What exactly is it that would "know" the organism would die and not reproduce?


Well, I'm just a laymen with some knowledge, that's all.

I see two others have already answered your question, but I will put it in my own words.

Nothing "knows" the organism will die, it simply dies. When an organism dies before it can reproduce, the mutation that led to that death will of course be lost, since it couldn't pass it along to its offspring. As you can see, there is no knowledge involved here, simple logic dictates this.

Is this not foreknowledge? Is this not thinking and reasoning?

No, if you die before you can reproduce, which is due to your body being weak/inadequate/whatever other reason, you can't pass along your genes, and thus the mutation that led to your dying "prematurely" will be lost, it's as simple as that.
This message is a reply to:
 Message 64 by ICdesign, posted 08-15-2010 7:15 PM ICdesign has responded

Replies to this message:
 Message 68 by ICdesign, posted 08-16-2010 5:06 AM Huntard has responded

    
ICdesign
Member (Idle past 2694 days)
Posts: 360
From: Phoenix Arizona USA
Joined: 03-10-2007


Message 68 of 75 (574465)
08-16-2010 5:06 AM
Reply to: Message 67 by Huntard
08-16-2010 2:59 AM


Re: Doh....!!
Hey. thank you guys for the courteous replies. Believe it or not (probably not ) I do understand the basic principals you guys are sharing with me. I would like to talk about how natural selection is actually super natural in the future some time but for now...

it seems to be clear to everyone but me so I guess I must be a dumb ass. To me if the organism isn't propagating because it would die if it did, then it would have to know it was going to die and make a choice based on that knowledge. "Would" die is a future event.

...have to dash off to work, bye...


This message is a reply to:
 Message 67 by Huntard, posted 08-16-2010 2:59 AM Huntard has responded

Replies to this message:
 Message 69 by Huntard, posted 08-16-2010 5:25 AM ICdesign has responded
 Message 70 by Dr Adequate, posted 08-16-2010 8:13 AM ICdesign has not yet responded

    
Huntard
Member (Idle past 192 days)
Posts: 2870
From: Limburg, The Netherlands
Joined: 09-02-2008


Message 69 of 75 (574468)
08-16-2010 5:25 AM
Reply to: Message 68 by ICdesign
08-16-2010 5:06 AM


Re: Doh....!!
ICDESIGN writes:

Hey. thank you guys for the courteous replies. Believe it or not (probably not ) I do understand the basic principals you guys are sharing with me. I would like to talk about how natural selection is actually super natural in the future some time but for now...


Sure, start a topic when ready.

it seems to be clear to everyone but me so I guess I must be a dumb ass. To me if the organism isn't propagating because it would die if it did, then it would have to know it was going to die and make a choice based on that knowledge.

But that's not what happens, nor what we said. The organism dies before it can reproduce, not becuause it reproduces. It doesn't "know" it will die by propagating, it dies before it is physically possible for it to do so (for example, it is still an infant). It would be like when a human is born with a serious birthdefect, this human than lives till the age of 4, then it dies. As you can see, 4 years of age is not enough to be physically able to reproduce, and so, the mutation that caused his birthdefects will not be passed on to its offspring, because it never made any. This is what we're trying to explain to you. If a mutation cause the RLN to "break" anytime before the organism is an adult (and be able to reproduce), leading to the death of the organism, then that mutaion will die off with that organism, because it never gets passed along.

"Would" die is a future event.

Yes, and if it dies before it is capable of reproducing (which is what we're going with in this scenario), then of course all of its bad mutations are lost.
This message is a reply to:
 Message 68 by ICdesign, posted 08-16-2010 5:06 AM ICdesign has responded

Replies to this message:
 Message 71 by ICdesign, posted 08-16-2010 3:59 PM Huntard has responded

    
Dr Adequate
Member
Posts: 16035
Joined: 07-20-2006
Member Rating: 3.8


Message 70 of 75 (574489)
08-16-2010 8:13 AM
Reply to: Message 68 by ICdesign
08-16-2010 5:06 AM


Re: Doh....!!
I would like to talk about how natural selection is actually super natural in the future some time but for now...

There's nothing supernatural about dead organisms not being able to reproduce. It would be kinda supernatural if they could.

it seems to be clear to everyone but me so I guess I must be a dumb ass. To me if the organism isn't propagating because it would die if it did, then it would have to know it was going to die and make a choice based on that knowledge. "Would" die is a future event.

As Huntard explained, it's not refraining from reproducing because it would die, but because it's dead.

I would also point out that there are organism which do die of reproducing. Salmon, for example, or male praying mantises. Obviously any mutation causing a salmon or mantis to refrain from reproducing would also be lost from the gene pool.


This message is a reply to:
 Message 68 by ICdesign, posted 08-16-2010 5:06 AM ICdesign has not yet responded

  
ICdesign
Member (Idle past 2694 days)
Posts: 360
From: Phoenix Arizona USA
Joined: 03-10-2007


Message 71 of 75 (574554)
08-16-2010 3:59 PM
Reply to: Message 69 by Huntard
08-16-2010 5:25 AM


Re: Doh....!!
If a mutation cause the RLN to "break" anytime before the organism is an adult (and be able to reproduce), leading to the death of the organism, then that mutation will die off with that organism, because it never gets passed along.

OK, That's not what I was getting out of what you said before. I understand your point of view when you word it this way. I must have been reading it with misguided emphasis on my part or something like that. Sorry about that.

I still have questions concerning that whole nerve stretching process from the TOE point of view but I will have to address them at a later date.

Thanks for your coolness and God's best laid plans to you,
IC


This message is a reply to:
 Message 69 by Huntard, posted 08-16-2010 5:25 AM Huntard has responded

Replies to this message:
 Message 72 by Percy, posted 08-16-2010 4:54 PM ICdesign has responded
 Message 73 by Huntard, posted 08-16-2010 5:39 PM ICdesign has not yet responded

    
Percy
Member
Posts: 17663
From: New Hampshire
Joined: 12-23-2000
Member Rating: 2.9


(1)
Message 72 of 75 (574559)
08-16-2010 4:54 PM
Reply to: Message 71 by ICdesign
08-16-2010 3:59 PM


Re: Doh....!!
ICDESIGN writes:

I still have questions concerning that whole nerve stretching process from the TOE point of view but I will have to address them at a later date.

The routing of the laryngeal nerve is genetic, but not the stretching.

The elongation of the nerve during fetal development and later growth into an adult is not under any specific genetic control. It's just the general growth and development process. It just happens naturally. The genes in individual cells under genetic control respond to the pressures and needs of their neighboring cells to cooperate in the growth process, but there's no specific genes telling everything precisely how much to grow.

The growth and development process is under the control of hormones and other body chemicals that are themselves under genetic control, but these hormones and chemicals are not carrying specific signals of "grow 1mm in this direction and 2mm in that direction." It's much more like just a general command to grow.

Children that are small for their age are sometimes given growth hormone. The hormone has no specific instructions for each nerve, muscle and bone in the body. It's more like a signal sent to everywhere in the body to grow. The body itself with all its cells in cooperation figures out how much to grow so that all the joints and bones and blood vessels and nerves still fit neatly together.

Here's an interesting picture:

As neck rings were gradually added the nerves, bones, blood vessels and everything else all stretched naturally in response. That is all that happens to the laryngeal nerve during growth and development. There was never any need for specific genetic control to make it stretch.

--Percy

Edited by Percy, : Clarify.


This message is a reply to:
 Message 71 by ICdesign, posted 08-16-2010 3:59 PM ICdesign has responded

Replies to this message:
 Message 74 by ICdesign, posted 08-16-2010 6:00 PM Percy has acknowledged this reply

    
Huntard
Member (Idle past 192 days)
Posts: 2870
From: Limburg, The Netherlands
Joined: 09-02-2008


Message 73 of 75 (574568)
08-16-2010 5:39 PM
Reply to: Message 71 by ICdesign
08-16-2010 3:59 PM


Re: Doh....!!
ICDESIGN writes:

OK, That's not what I was getting out of what you said before. I understand your point of view when you word it this way. I must have been reading it with misguided emphasis on my part or something like that. Sorry about that.


No problem mate, glad you got it now.

I still have questions concerning that whole nerve stretching process from the TOE point of view but I will have to address them at a later date.

Sure, whenever you're ready, though I think Percy already went ahead and explained it a bit.

Thanks for your coolness and God's best laid plans to you,

You're welcome, as long as we all keep our cool, discussion will be quite pleasant I think.
This message is a reply to:
 Message 71 by ICdesign, posted 08-16-2010 3:59 PM ICdesign has not yet responded

    
ICdesign
Member (Idle past 2694 days)
Posts: 360
From: Phoenix Arizona USA
Joined: 03-10-2007


(1)
Message 74 of 75 (574575)
08-16-2010 6:00 PM
Reply to: Message 72 by Percy
08-16-2010 4:54 PM


Re: Doh....!!
Hi Percy,

Thanks for your informative post. What you say seems to be a pretty good blend of TOE and what actually takes place due to God's grand design and programming.

I am very impressed with your knowledge as well as the way you present it so thanks again.

I think I will have some pretty challenging presentations for you guys in the not too distant future and I look forward to some friendly debates and thought provoking discussions

RESPECTFULLY,
IC


This message is a reply to:
 Message 72 by Percy, posted 08-16-2010 4:54 PM Percy has acknowledged this reply

    
MrTim
Junior Member
Posts: 1
Joined: 06-14-2018


Message 75 of 75 (835369)
06-22-2018 9:04 AM
Reply to: Message 1 by slevesque
08-06-2010 3:41 PM


Hello slevesque and everyone else.

I've read through this thread and the previous one on the RLN. It seems like the answer to the original question in part I was not found, and I've been debating this subject on another forum so have thought a bit about what the reason for the circuitous route might be. Apologies in advance if I waffle a bit.

As you say, the branch from the vagus that we call the recurrent laryngeal nerve supplies the trachea, upper 1/3 of the esophagus, and the lower part of the larynx. (It also sends a few filaments to the cardiac plexus).

There is already a nerve to the upper part of the larynx, also a branch of the vagus. This supplies cricothyroid muscle with efferent fibres and the mucosa of the larynx above the glottis (the gap between the vocal folds) with afferent fibres.

It makes sense for the inferior laryngeal nerve to approach the larynx from below, so that it can slip underneath muscles such as cricopharyngeus, on its way to the rest of the laryngeal muscles and the mucosa below the glottis. That's fine; however, why does it need to come up all the way from the bottom of the trachea, rather than just from say the first tracheal cartilage?

We need to bear in mind that the trachea starts off as a tiny outpouching of the foregut called the respiratory diverticulum. Suppose that the nerve supply to the portion of the larynx formed from the sixth branchial arch, becomes attached before the trachea and esophagus start to elongate. In order for it to maintain its orientation from below, it could be made secure by an attachment to the foregut.

As the trachea and esophagus lengthen, the nerve will also. By looping under the subclavian artery or aorta, a tethering effect is created that maintains the caudal-cranial direction of the nerve so that it enters the larynx from below.

Also bear in mind that the cell bodies for the nerve fibres contained in the RLN are found in one region of the medulla (the nucleus ambiguus). This suggests that they are a functional unit, which explains why they travel in the same nerve.

With most vertebrates, the neck is not so long that this arrangement would seem inappropriate. Only in some animals does it seem 'too long'.

The arrangement is not a complete waste of 'nerve length', as some would describe it: If there were lots of separate branches coming off the vagus for the lower larynx, trachea, esophagus and cardiac plexus, these branches would be longer than the branches that come from the RLN as they now do. They would have to travel further to get to the structure they supply. For an animal with a relatively short neck, the recurrent route may not add a great deal of nerve length overall, when alternative branching arrangements are considered.

So a common design would lead to a few animals having a very long nerve length, but that would not negate the overall logic of using such an arrangement.

That the heart may be part of this functional unit is suggested by the increase in heart rate we get when we breathe in. Vocalizing causes a 'change in the change' in heart rate, if you get my meaning.

I think that is all I had to say. I have made the assumption that an attachment from the vagus to the lower larynx is established early on.

Hope that is of some help.

Edited by Adminnemooseus, : Added blank lines between paragraphs.


This message is a reply to:
 Message 1 by slevesque, posted 08-06-2010 3:41 PM slevesque has not yet responded

    
Prev1234
5
Newer Topic | Older Topic
Jump to:


Copyright 2001-2015 by EvC Forum, All Rights Reserved

™ Version 4.0 Beta
Innovative software from Qwixotic © 2018