Fom what I could gather, signalling molecules are part of genes.
Absolutely not. what many signalling molecules are is the product of genes.
One big problem with this approach of yours is that the term 'signalling molecule' can refer to a huge range of things. Hormones are signalling molecules, growth factors and many other proteins are signalling molecules even proteins attached to the outside of the cell can be signalling molecules.
Add to this that arguably any number of proteins involved in the signalling cascade once a signal from outside the cell has been received could be considered 'signalling molecules' and you have a vast array of possible elements.
The simplest sort of signalling is that seen with steroid hormones. Because they are lipophilic these hormones can easily cross the cell membrane and meet up with steroid receptor proteins which carry them into the nucleus and which can bind to specific regions of the nuclear DNA and which behave differently in the presence or absence of hormones. In some cases the receptors actually stay in the nucleus and the hormone passes through the nuclear membrane on its own as well.
Other types of signalling are considerably more complex and rely on cascades of proteins being activated to relay a signal from the cell surface to the activation of proteins affecting transcription in the nucleus. These cascades can involve dozens of proteins, one well studied example is the MAP kinase signalling pathway.
I don't see any similarity to a computer myself, but then I know a lot more about biology than I know about computers. The whole encoding-decoding thing seems to be completely missing. The only obvious candidate for encoding-decoding anywhere in the system is the transcription and translation of mRNA.
Perhaps if you are thinking in a developmental context you are considering the transmission of what is called positional information as a form of encoding-decoding. Positional information is the term given to the variety of factors acting upon a particular set of cells in a developing embryo which lead to it developing into a particular tissue. The simplest way of conveying positional information is a simple gradient of a signalling molecule. Different levels of receptor activation lead to the activation of different genes within the cell causing cells closer to the signal source to have a different character to those further away, the classic illustration of this is Lewis Wolpert's 'French Flag' model.
Thanks for adding your expertise here Wounded King. I've enjoyed reading your posts elsewhere. Maybe if I read this one ten times more, I'll be making sense out of it LOL.
What would be your opinion about how signaling molecules evolved? If I'm thinking like an IDer, I might (with a total lack of scientific knowledge) look at what you've written here and be amazed and incredulous at the complexity. What an intricate system. It does almost sound like there's a language here, with messengers carrying it.
People here have been helpful in explaining how IC is nonsense. Here is an excellent refutation of Behe's analogy of the mousetrap. It simply involves an unwillingness to accept that we do understand how things work, and anyone can find this out with a little education.
Thanks to you and others here for clarifying the signaling molecules. This obviously goes beyond my high school chemistry.
At the bottom of it all, the IDer thinks the whole of science is a conspiracy (a Communist one). He has to, because it's the only way he can refute anything scientific. He tries to argue that my finding information from websites, books and scientists is akin to his pulling information off of Hovind's site. The only problem there is that I am educating myself while he is deluding himself.
I take it that the author was not quite right there, and that mutations tend not to be as commonly harmful as he suggests. Otherwise we would not see organisms evolving as they have done.
He was surprisingly accurate. Most genetic mutations that have an effect on the phenotype...on the biochemistry, are harmful. A suitably complex biochemical structure is much more likely to be ruined by even a slight change than it is to be improved. Populations tend to find themselves either evolving in light of environmental change, or more generally they find themselves in equilibrium - all the phenotypes are generally clustered around an optimum, and deviating from the optimum is likely to result in selection culling things back. It's only when the optimum changes that we see the mutations that might make the organism less badly adapted for the new environment.
The thing is Taz, you do need certain components for your computer to work; remove one of those, and the system will not function.
Here is something for you to think about. Without a processor, is the computer really a computer anymore?
You've stumbled onto another reason why IC is bullshit. Of course the computer won't function because it's not a computer anymore once you've removed something that made it a computer. Same thing with the cell. If you remove the lipid bilayer, of course it's not going to function as a cell anymore because it's not a cell anymore.
A monitor, a keyboard (the system might work but you can't use it without those).
I beg to differ. I can write this entire post without touching my keyboard once. It might be tideous, but i can be done. :)
I think an IDer might reply to you that any equivalent vital components in a biological system would be equally devastating to the functioning of the organism if one or more was removed.
Sure, and that in itself is a strawman. Is it really a functioning duck anymore once you've removed the head? Just because you can remove a component that make it something else doesn't mean it's irreducibly complex like the way they say it.
I also want to point out another point that it has now become clear to me that you don't know about.
The ID's entire argument is if you remove a vital component it will stop working and therefore the whole thing is irreducibly complex which indicates a creator. I've been assuming that you know this is an obvious strawman, but I guess not.
Why is it a strawman? Because evolution doesn't mean adding a whole new component as is to the entire system right there and then. Evolution is about modifying already existing components to allow the system to better survive in the environment.
Try to think of it like the evolution of computer. The first computers had vacuum tubes. Then they had transistors which were a lot more efficient. Third generation computers (current computers) have chips. 4th generation computers will be quantum computers.
Computers didn't just appear on the market fully equipped with microchips. They went through stages.
When IDists speak of cells being irreducibly complex, they want you to believe that biologists claim that it appeared out of nowhere fully formed and functional with all the organelles, mitochondria, and microtibules. This is obviously bullshit strawman. The cell went through many stages of modifications. We know that lipid bilayers form on their own in nature. We know that given the right conditions precells can form on their own with their very primitive metabolism. Even precells have many stages.
Take a look at the eye as the most used example of IC. Currently, we have an example for every step of the evolution of the eye, from light sensitive cells on microorganisms to the eyespots on flatworms to eyes without components like the lense (nautilus) to our eyes. Even the eye have many branches of evolution. For example, the octopus' eye is a lot better than our eyes, having their nerves in the back instead of the front thus not interfering with the image vision.
Occasionally, owing to the deficiency of the English language, I have used he/him/his meaning he or she/him or her/his or her in order to avoid awkwardness of style.
He, him, and his are not intended as exclusively masculine pronouns. They may refer to either sex or to both sexes!
Yes, he's asked about the eye. I've given him info on that; as you say, living organisms display the full spectrum from the very simple to the complex.
I think I'm going to take the tactic of showing what BS the IC argument is. If he gets me to keep talking about signaling molecules, I can't talk like WK with any semblance of credibility. I'll end up like the astronomer who was trounced in that debate you mentioned.
So how would signaling molecules work to produce bilateral symmetry? What are they "stopping"?
So the other way a signaling molecule can work is by removing a monkey wrench that's already there, see? Because an enzyme can work on another enzyme, and disengage something that's blocking protein synthesis.
This is very roughly how gene expression can be controlled.
Thanks crashfrog and RAZD. I'll look up these links.
Thinking about what this creo has said to me, his other favourite tactic parallel to this one is the argument from incredulity. He insists that many things are too complicated to have evolved; they must have been created. That's what's driven me to try to explain so many things to him. But in the end it's going to be a waste of time because he's not really interested in the answers, or he'd look them up himself.
I'm going to make some notes on the things people have told me here. The knowledge shared here is fantastic, and thanks to all for your help.