G-Proteins: The Molecular Switch

Imagine you are a soldier on a very dangerous patrol in Afghanistan. While your conscious brain attends to the environment, looking for suspicious activity, the unconscious part of your brain is busy altering your body’s physiology in anticipation of an impending threat. Your heart will start to beat faster and much of your blood that would otherwise be traveling to your kidneys and digestive organs is rerouted to your muscles and nervous system. The liver dumps extra sugar into your blood and the airways in your lungs open wider, allowing them to deliver more oxygen to the blood that pulses more quickly. Your sweat glands are more active and the pupils of your eyes dilate. This is what is called the “fight or flight” response, made possible by the hormone epinephrine, better known as adrenalin. The net result of this response is that your muscles are stronger and faster and your brain is more alert. In other words, your body is optimized to fight the enemy, or if need be, to flee.

To get from the state of fear to a body that is better able to respond to fear, many signal “transitions” are involved. The awareness of a threat is “translated” into an electric current that travels along a distinct network of nerves known as the sympathetic nervous system. The electric current is then “translated” into a release of the hormone epinephrine. This hormone will then bind receptors on heart muscle cells, blood vessels cells, liver cells, etc. Thus cells will then “translate” the message of “epinephrine” into rising levels of cyclic AMP (cAMP) inside the cell. In other words, “fear” becomes high cellular concentrations of cAMP, which in turn activate a circuit of proteins to bring about altered cellular activity, which then results in the effects cited above.

Front-loading and Preadaptation

Cooption, the process by which traits switch function, is something we predict to be important from the hypothesis of front-loading evolution. The Design Matrix lays out a step-by-step case for the logic of front-loading that leads to the realization that cooption is entailed by front-loading. Functional shifts are the very strategy that would work in an attempt to design the future through the present. This is a subtle, but important, point to grasp. Cooption is not some add-on to the front-loading perspective. Cooption is a prediction given that front-loading would not work without it.

Yet there is a simpler way to help people understand that cooption is, at the very least, a process that fits very comfortably within a teleological framework. It is the simple fact that cooption is tightly linked to preadaptation. Stephen Jay Gould sought to replace the word ‘preadaptation’ with the word ‘exaptation,’ where an exaptation is a character that retains its ancestral form while taking on a new function. And the process by which the trait switches function is called cooption.

The concept of preadaptation has been recognized by many to possess distinct teleological connotations, which is why non-teleologists have sought to replace it. This point is easily established:

Biotic Bolts

We have seen that some critics have acknowledged that evidence of bolts in biology would amount to evidence of design. So are there any bolts in life?

If we hypothesize that life is indeed carbon-based nanotechnology, we ought not expect that the bolts used by life would have the same form and composition as those used in your car or lawnmower. Instead, we need to think of the design objective that the bolt carries out – it is a device used to connect things. By bolting parts together, we are holding the independent parts of a machine together such that the various parts can function as a whole. This generic function explains why we find bolts in all sorts of unrelated machines.

So does the cell contain such bolts?

It would seem so.

Ascension

Instructive Moments

Over at TT, Bilbo asks, “What would Positive Evidence for ID Look Like?,” and briefly outlines the four criteria of the Design Matrix. Three critics responded and their responses are actually quite instructive.

The Origin

Another Approach

As I have noted before, something I call the Traditional Template shapes the way most minds approach the issue of design in biology. Basically, the Traditional Template builds on the false dichotomy of “evolution vs. design,” where both sides seem to agree that in order to find evidence of design, we need to disprove the evolution of some feature.

I have suggested an alternative approach.

1. Instead of approaching the issue like a philosopher trying to establish design in one step, approach the issue as a detective looking for clues – inductive gradualism.

2. Instead of taking a negative approach that revolves around skepticism about evolution, take a positive approach that seeks out signals we might expect to see if design occurred.

3. Recognize that we cannot objectively measure design, as “detecting design” is akin to detecting another mind.

Throughout all of this, we need to strive to remain open-minded and intellectually honest, trying to strike the balance between confirmation bias and disconfirmation bias.

Evidence and Assumptions

Stanley Fish is the Davidson-Kahn Distinguished University Professor and a professor of law at Florida International University, in Miami.. He has written a nice article addressing the debate du jour about faith and reason. I draw attention to it here simply because he makes a point that should be familiar to anyone who has read The Design Matrix. It is a point that is crucial to grasping the core argument of the book. Have a look:

10 Signs of Intellectual Honesty

I can never post this too much…

When it comes to just about any topic, it seems as if the public discourse on the internet is dominated by rhetoric and propaganda. People are either selling products or ideology. In fact, just because someone may come across as calm and knowledgeable does not mean you should let your guard down and trust what they say. What you need to look for is a track record of intellectual honesty. Let me therefore propose 10 signs of intellectual honesty.

The Brain

Let’s consider the human brain:

The human brain contains about 10 billion nerve cells, or neurons. On average, each neuron is connected to other neurons through about 10 000 synapses. (The actual figures vary greatly, depending on the local neuroanatomy.) The brain’s network of neurons forms a massively parallel information processing system. This contrasts with conventional computers, in which a single processor executes a single series of instructions.

Against this, consider the time taken for each elementary operation: neurons typically operate at a maximum rate of about 100 Hz, while a conventional CPU carries out several hundred million machine level operations per second. Despite of being built with very slow hardware, the brain has quite remarkable capabilities:

• its performance tends to degrade gracefully under partial damage. In contrast, most programs and engineered systems are brittle: if you remove some arbitrary parts, very likely the whole will cease to function.
• it can learn (reorganize itself) from experience.
• this means that partial recovery from damage is possible if healthy units can learn to take over the functions previously carried out by the damaged areas.
• it performs massively parallel computations extremely efficiently. For example, complex visual perception occurs within less than 100 ms, that is, 10 processing steps
• it supports our intelligence and self-awareness. (Nobody knows yet how this occurs.)

The question we will next consider is whether there are features of the cell’s design, not necessary for cellular life, yet necessary to make a brain.