Posted on 06/01/2009 8:11:20 PM PDT by GodGunsGuts
Physicists Finding Perfection...in Biology
June 1, 2009
Biologic Staff
When we think of simple, elegant, unifying principles in science, we think of physics. It’s not surprising then that physicists who examine living systems are looking for principles of this kind.
And it seems they have found one. Simply stated, it is that biological processes tend to be optimal in cases where this can be tested. Life’s complexity can make it hard to pinpoint what “optimal” means, but sometimes physical limits provide a crisp definition. Because these limits cannot possibly be exceeded, they serve as an objective standard of perfection. Interestingly, in cases where it is clearly beneficial to edge right up to this standard, that’s exactly what life seems to do.
For decades enzymologists have recognized that certain enzymes are catalytically perfect—meaning that they process reactant molecules as rapidly as these molecules can reach them by diffusion. [1] That hinted at a principle of physical perfection in biology, but no one anticipated its breadth until recently. According to Princeton physicist William Bialek, one of the leading proponents of the emerging principle, “The idea of performance near the physical limits crosses many levels of biological organization, from single molecules to cells to perception and learning in the brain.” [2] He observes that “While it is popular to view biological mechanisms as an historical record of evolutionary and developmental compromises, these observations on functional performance point toward a very different view of life as having selected a set of near optimal mechanisms for its most crucial tasks.” [2]
Bialek is interested in determining whether this principle will continue to hold up as more and more biophysical systems are tested against it. But it’s also interesting to ponder how such a principle can be explained. In particular, which origins paradigm does it best cohere with—the Darwinian one or the design one?
Although the Darwinian mechanism has some capacity to optimize, perfection seems to be well beyond its reach. Its handicap lies in the kind of optimizer it is—a local one, not a global one. That is, it produces not the best solution to a problem but rather the best available solution—meaning available by chance to a species in which the problem has not yet been solved.
If it’s reasonable to think that a complex problem that hasn’t been solved at all is not even close to having been solved well (and it seems that it is), then surely the best available solution under such dire circumstances is not apt to be a good one. Even after all the available chance improvements are exhausted, you would expect to be left with something makeshift, far from perfect.
So, while most biologists like to think that Darwinism can deliver perfection, that notion evaporates very quickly under critical scrutiny. Now that perfection is becoming a recognized principle in biology, perhaps it’s time for biologists to join the physicists in grappling with it.
Ping!
I saw in a documentary Mike Tyson wanted to fight a gorilla.
The article used massive generalities centering briefly on enzymes as some sort of proof. The authors could as well mentioned enzyme linked immunosorbant assays (ELISA) for their point. At least, then, it would have been a process. Both enzymes and antigenic reaction require a specific site of attachment for the agent to bind and do work (work loosely defined as any function). There is no almost fit - it either binds or not. The authors premise that evolution requires random best fit is flawed. Using antigenic reactions as an easy example you will find that when presented with a foreign entity for the first time, the host does not have a specific antigenic response. Only when the host acclimates and creates new antibodies that are specific to that antigen will the host be able to recognize and eliminate the foreign body (antigen). This is the reason why we were all subjected to small pox vaccines back in the day - to develop a response.
In short, the biology staff in the article used known systemics to make broad unsupported generalities.
I don't think Barack will allow Michelle to do it.
==Both enzymes and antigenic reaction require a specific site of attachment for the agent to bind and do work (work loosely defined as any function). There is no almost fit - it either binds or not.
That’s not exactly accurate. There are a number of enzymes that can catalize multiple, slightly different chemical reactions using substrates that have the same general structure. Here is but one example:
“Both enzymes catalyze multiple steps in BR biosynthesis: 6-deoxoteasterone to teasterone, 3-dehydro-6-deoxoteasterone to 3-dehydroteasterone, 6-deoxotyphasterol to typhasterol, and 6-deoxocastasterone to castasterone. Our results indicate that the AtBR6ox gene and the tomato Dwarf gene encode steroid-6-oxidases and that these enzymes have a broad substrate specificity.”
Yeah but, all those websites featuring biologically perfect females are blocked at work.
Thanks for the ping!
Thanks , the post deserved a better level of commentary than it got.
Just like astro-biology.
True an enzyme can act as a catalyst in several stages of a reaction, however the binding site must and is always identicle.
Here's what Dr. Bialek actually wrote,
"Strikingly, when we do this (and there are not so many cases where it has been done!), the performance of biological systems often approaches some limits set by basic physical principles."
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