The Blood Clotting Cascade Mechanism

[BGoodForGoodSake]

Before we begin this discussion we need to first understand the cascade system.

http://www.surgical-tutor.org.uk/defaul ... .htm~right

And point out why is a cascade with so many steps the best design?
Why not fewer or more or more straightforward?

Also contrary to KMart's claims this argument has been successfully refuted before, however I will take a completely novel approach.

So...
would anyone care to take a shot at answering the questions?

[August]

Why don't you start by giving us a complete explanation of how the blood-clotting cascade came to be via the mechanisms of evolution, backed up by experimental evidence?

[Byblos]

^ and at what stage on the evolutionary ladder did it go wrong so as to become a not so ideal design.

It seems that you're looking for a perfect design or lack thereof, to disprove ID. Your intent will backfire my friend as it is precisely the imperfection of the design that goes to the heart of ID. For without it there can be no free will and, by extension, you would not have the freedom to disagree with it.

[AttentionKMartShoppers]

To be successfully refuted, one must explain how the blood clotting cascade could come about through the mechanisms of random chance and natural selection...and explain how the organism clotted during the transformation so it wouldn't die of blood loss...and what kept a clot from occurring throughout the blood stream. Stop telling me stuff has happenned...site it or quote it. Pretty please, in all your wisdom great one (happy Kurieou?)

[BGoodForGoodSake]

Why don't you start by giving us a complete explanation of how the blood-clotting cascade came to be via the mechanisms of evolution, backed up by experimental evidence?

Because that has already been done, I am going to take a different approach. Also if we don't yet have all the answer it would be preposterous to do anything more than speculate on the posible evolutionary steps the clotting mechanism has taken to get to where it is today.

[BGoodForGoodSake]

Fine then lets continue.

I am assuming that everyone has read the background material and has a general understaning of the cascading clotting mechanism of vertabrates.

First question which needs to be asked is what is the advantage of having so many different proteins involved in the cascading sequence?

And which proteins are really essential for the clotting mechanism to work.

[BGoodForGoodSake]

Well the cascade is very complex indeed as the many factors interact with those down the line and also with those before them in the cascade. This seems very complex until you realize that many of the factors are very similar in build. Perhaps they are the result of duplicate genes which have diverged? No matter lets continue.

The only required protein is of course fibrinogen and the protease which works on it. In this case its thrombin. The thrombin breaks the fibrinogen apart and allows the resulting proteins to stick together.

Another thing to keep in mind is that there are two pathways the extrinsic and the intrinsic pathway. However the extrinsic pathway is much faster compared to the reaction time of the intrinsic pathway. So why have the intrinsic pathway in the first place? Well the intrinsic system responds to damage to cell surfaces as in a cut. While the extrinsic system responds to proteins only found in the bodies tissues not in the bloodstream. This pathway would be activated in the case lets say that your kidney is hemorrhaging.

The intrinsic pathway also creates in the cascading enzymatic action, an anti-thrombin which ceases the action of the protease thrombin (ie. stops clotting). This gives us a clue into why there are so many steps in the intrinsic pathway.

Now we need an analogy to simplify this discussion. Don't worry we will always refer back to the actual chemistry and not depend on the analogy so much. It is only to help us get a picture in our minds to work with.

Lets use a management ladder for the intrinsic pathway, and for the extrinsic one we will use, the emergency response system, like a firehouse.

Now before we go into the next section we need a basic understanding of what a protease is.

It is an enzyme which acts on proteins.

And how do enzymes work?
hardhttp://academic.brooklyn.cuny.edu/biolo ... ow_enz.htm
mediumhttp://science.howstuffworks.com/cell2.htm
easyhttp://www.tvdsb.on.ca/westmin/science/ ... nzymes.htm
Great I'm sure everyone had fun reading that material.
=)

Ok cool, now we can continue. Imagine that each protease can convert 4 molecules a minute.

Now in a thromin fibrinogen system the only enzymatic activity is the thrombin cutting the fibrinogen.
In an organism such as this, like the modern lobster the thrombin material is stored intracellularly. The thrombin is realeased and the process is very slow. So we have
Minute 1 4 fibrinogens cut
Minute 2 4 fibrinogens cut
Minute 3 4 fibrinogens cut
Minute 4 4 fibrinogens cut
Result 16 fibrinogens cut. In a vertebrate with a high pressure vascular system I would have bled to death.

Now lets add a cascade level.
We now have prothrombin in the blood and factor X to cut it is now residing intracellularly. The cell is now damaged releasing factor X. Each factor X cuts 4 molecules a minute, and what is it cutting? Prothrombin.
Each Prothrombin becomes a Thrombin protease which in turn cuts 4 Fibrinogen's a minute. So we have
Minute 1 4 prothrombins cut
Minute 1 4 prothrombins cut 16 fibrinogens cut
Minute 1 4 prothrombins cut 32 fibrinogens cut
Minute 1 4 prothrombins cut 48 fibrinogens cut
Result 96 fibrinogens cut. Increddible I add one step and the process is now 6 times faster!

Now lets take a look at the intrinsic system where there is only one protease acting on factor X. In this system factor X is in an inactive form and requires an enzyme to activate it. Lets call this enzyme factor IX.
When a cell is damaged there are proteins on the surface of a cell which will activate factor IX. So we have.
Minute 1 4 factor IX cut
Minute 2 4 factor IX cut 16 Factor X cut
Minute 3 4 factor IX cut 32 Factor X cut 64 prothrombins cut
Minute 4 4 factor IX cut 48 Factor X cut 128 prothrombins cut 256 fibrinogens cut

So now we can see why there is an advantage to having multiple steps. A small stimulus gets amplified greatly!

One should note that adding more cascading steps will delay the point where actual Thrombine is active. but at this point it will be a large amount of proteins working.

Ok great we have answered the innitial questions. What now?
Well next we will examine the factors more closely and see how they interact.
And we will answer this question, why not add one more step to make the process even faster?

[AttentionKMartShoppers]

Why don't you start by giving us a complete explanation of how the blood-clotting cascade came to be via the mechanisms of evolution, backed up by experimental evidence?

Because that has already been done, I am going to take a different approach. Also if we don't yet have all the answer it would be preposterous to do anything more than speculate on the posible evolutionary steps the clotting mechanism has taken to get to where it is today.

You keep on saying that..."it's been done"....but you want us to take this on BLIND FAITH? Uh, no thank you.

And, you've....told a lovely story backing up Behe-instead of saying "well, there used to be a simpler path..." you instead say "wow, look at the great advantages of two blood clotting pathways! Are you on our side or are you trying to prove us wrong and showing that IR biological machines can in fact be put together via evolution?

[BGoodForGoodSake]

Why don't you start by giving us a complete explanation of how the blood-clotting cascade came to be via the mechanisms of evolution, backed up by experimental evidence?

Because that has already been done, I am going to take a different approach. Also if we don't yet have all the answer it would be preposterous to do anything more than speculate on the posible evolutionary steps the clotting mechanism has taken to get to where it is today.

You keep on saying that..."it's been done"....but you want us to take this on BLIND FAITH? Uh, no thank you.

And, you've....told a lovely story backing up Behe-instead of saying "well, there used to be a simpler path..." you instead say "wow, look at the great advantages of two blood clotting pathways! Are you on our side or are you trying to prove us wrong and showing that IR biological machines can in fact be put together via evolution?

I'm getting there, I thought you would be able to appreciate that I am laying the framework for a discussion. Who cares if its been done before or not, I wanted to use a novel approach, read the first post.
Please read posts before responding.

I will give you a link to an example of rebuttal but only after we have finished this discussion, because I know that it will take away from our discussion and take things off topic. Please, I am putting alot of effort and time into this discussion, if you are going to persist in sabataging the effort, I am going to have to beg you to stop.

[AttentionKMartShoppers]

"Conceals TNT behind back" sabotage? And I am reading your posts, how else would I be able to respond to them and quote them-I have to read them first-it's a rather well known phenomenon. And, as I found out when I started debating-you can't make claims-you have to back them up with something, or they're hollow and meaningless.

[Jbuza]

And point out why is a cascade with so many steps the best design?

Why not fewer or more or more straightforward?


What is the point of these questions? Are you asking if happenstance could have created a more streamlined design? I don't understand what you are looking for here. How about lets design a working alternative that is more simple. From a strictly scientific approach the most simple system to answer the need should be in place. IF there is in fact a cascade mechanism with "fewer or more straightforward steps" that would answer the need than it would only point to design. REdudant failsafes, complex interactions, these aren't the realm of science they are the realm of design.

[AttentionKMartShoppers]

In the other top thread in god and science I posted the entire chapter where Behe talks on the cascade. Start there.

[Jbuza]

And we will answer this question, why not add one more step to make the process even faster?


People already have problems with clot formations, wouldn't speeding up or improving the clotting factor of blood lead to more stroked and heart attacks. It is not possible to improve on the clotting factor of blood. Because an intelligence far beyond ours created it.

[Kurieuo]

I've been following to some extent these many design discussions. Quite frankly, I don't feel the issue raised is being dealt with. Both sides seem focused on two entirely different topics. Kmart appears more focused on "irreducible complexity," which is the topic I believe this all begun with. And BGood appears focused on the whodunnit factor (i.e., God) judging by the original questions of this thread. When I saw that KMart was introducing the blood clotting system, I saw it being presented as a case of an "irreducibly complex" system devoid of whodunnit.

The questions of "why is a cascade with so many steps the best design?" or "Why not fewer or more or more straightforward?" is simply irrelevent to what I see KMart has been trying emphasise—that irreducibily complex systems exist within biology. Yet such questions are also irrelevant for different reasons when put forward against Christian theism (not ID—note the difference), because in the end no matter what an all-powerful God would design, one can always say "well why didn't he do it better?" Of course unless God creates God which is logically impossible (for anything created wouldn't have been eternal), it can always be asked why didn't God make something better. Therefore a fallacy is committed within such questions, because 1) they rig standards logically unattainable in any system if such a system was indeed designed by an all-powerful God; and 2) they beg the question in assuming God's purpose in creating was to create the most perfect world.

Getting off the topic of "theism" now, and somewhat back to ID and its "irredicible complexity," it is no good to simply say, "such a system has been described" (that is, how the blood clotting system gradually arose has been described), and then want to leave it at that. Isn't this point one of the main points of focus throughout all these discussions? If I began a discussion that sets out to prove God exists, non-theists respond, and then I declare that God does exist because he has been experienced by people. Surely, I am not in some way being intellectually unfair in proclaiming I'm right without really getting into the discussion? So if how blood clotting arose can be described in a step-by-step evolutionary manner (which would show it isn't "irreducibly complex"), then please provide the relevant scientific articles.

Additional note: In relation to this last paragraph, I just noticed the post I was referring to has now been edited, so to some extent it doesn't apply anymore, although articles describing how the blood clotting process gradually came about would be still appropriate to refuting that such a system is irreducibily complex.

Kurieuo

[August]

Because that has already been done, I am going to take a different approach. Also if we don't yet have all the answer it would be preposterous to do anything more than speculate on the posible evolutionary steps the clotting mechanism has taken to get to where it is today.

I'm confused. First you say that it has already been done, and then you say we may not have all the answers yet. Which is it?

Also, you are asking us to assume that the position that you are attempting to defend has "already been done". The contra position to IC is reducible, then you have to show the reducability via the evolutionary pathway to prove the contra. Anything else ends up somewhere in the middle.

Why do you find it necessary to take a different approach if all you have to do is show us where it has already been done?

Anyhow, please continue with your different approach, you have me quite curious.