Freitag, 18. Juni 2010

Life is soft condensed matter

So here I come back to define Biological Life once again.....

Biological life.

I believe that no solid definition has yet been provided for it, creating a dangerous void in the very foundations of life-sciences. I would like to give my own definition of life as I see fit in a physico-chemical perspective.

A system capable of modifying its internal architecture as a response to a change in its external environment is called living.

The word 'capable' actually plays a much more important role than any other here.

This appears to be a dangerously general definition of life as it seems to apply to anything 'material' in nature. But I have strong reasons to forward it this way, reasons that I will try to explain by giving a exemplary case.
Consider a case of a bacterium. What distinguishes it from a a piece of plastic which is considered 'non-living'? Only that the bacterium is more complexly organized and generates larger types of responses to external stimuli than the piece of a plastic. So if I build a huge/small (Hail nanotech!) plastic object made up of very different' kinds' of plastics and which is made so complex that it generates different kinds of responses to different kinds of stimuli, QUANTITATIVELY EQUIVALENT to those displayed by the bacterium, then shall we call the construct living?

If I understand the problem correctly, its actually related to a degenerate viewpoint of biologists that they have been TAUGHT to consider life as something as and more complex than a bacterium. This rigidity actually precludes a detailed investigation of the phenomenon of life and creates many barriers to a unified understanding of biology from other physical sciences. IF one wishes to remove the inherent generality in the definition I state above, it is possible to define life quantitatively by some measure of complexity. But not going into such details I will proceed henceforth into specific terminology to expatiate my claims.

What needs to be understood is the general characteristic of all the living organisms, deemed 'Living' by scientists.


Necessary and sufficient

There is only one character actually. It is ability to survive or cope IN A GIVEN ENVIRONMENT. As long as the environment is unchanged or changes with a sufficiently small a rate the entity survives and is called Living. This proposition is true for all living organisms starting from a bacterium to the Immensely complex higher eukaryotes.

Now there is a very important reason when I said in above sentence that if the environment changes with sufficiently small rate. Because it gives us another character that is NOT the property of the entity in itself in most of the cases, but of a population. That character is the ability to EVOLVE.



WHY EVOLUTION?

Survival is a dynamic concept in most cases. That is to say that its an environment dependent quality. To be truly living, i.e. surviving under all circumstances, there has to be one more quality. EVOLUTION. The ability to modify oneself to suit the environment. Now Biological evolution for almost all organisms is DARWINIAN, i.e. evolution by inheritable random mutations. As the environment can not be expected to be static as a general rule evolution is an artificial necessity.


Soft condensed matter

Now soft condensed matter is defined as substances whose molecules can be made to move significant distances by the application of comparatively weak forces. Furthermore, soft condensed matter is easily deformed by external stresses, electromagnetic fields, and thermal fluctuations. The field of soft condensed matter consists of polymers, liquid crystals, colloids, and biological materials.

Now this definition actually tells us that soft-condensed matter is most susceptible to environmental changes than the traditional 'hard matter'. AND it tells us that it is an ideal candidate for the definition of life as defined above. Also it clearly possesses the ability to evolve as environmental forces can alter its properties.


Fact of the matter

All the life on earth is actually constituted of soft condensed matter with drastically few exceptions. And even more these exceptions (e.g. crystalline matter) it is very closely associated with soft condensed matter. e.g DNA proteins lipids carbohydrates are your classical soft condensed materials.


Concluding remarks

(to be determined)



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