(ITA - 2003 - 1 fase)What is life?To the physicist
(ITA - 2003 - 1ª fase)
What is life?
To the physicist the two distinguishing features of 1living systems are complexity and organization. Even a simple 2single-celled organism, primitive as it is, displays an intricacy and fidelity unmatched by any product of human ingenuity. Consider, for example, a 3lowly bacterium. 4Close inspection reveals a complex network of function and form. The bacterium may interact with its environment in a variety of ways, propelling itself, attacking enemies, moving towards or away from external 5stimuli, exchanging material in a controlled fashion. Its internal workings resemble a vast city in organization. Much of the control rests with the cell nucleus, wherein is also contained the genetic ‘code’, the chemical blue print that enables the bacterium to replicate. The chemical structures that control and direct all this activity may involve molecules with as many as a million atoms strung together in a complicated 6yet highly specific way. (...)
It is important to appreciate that a biological organism is made from perfectly ordinary atoms. (...) An atom of carbon, hydrogen, oxygen, or phosphorus inside a living cell is no different from a similar atom outside, and there is a steady stream of such atoms passing into and out of all biological organisms. Clearly, then, life cannot be reduced to a property of an organism’s constituent parts. Life is not a cumulative phenomenon like, for example, weight. For though we may not doubt that a cat or a geranium is living, we would search in vain for any sign that an individual catatom or geranium-atom is living.
Sometimes this appears paradoxical. How can a collection of inanimate atoms be animate? Some people have argued that it is impossible to build life out of non-life, so there must be an additional, non-material, ingredient within all living things – a life-force – or spiritual essence which owes its origin, ultimately, to God. This is the ancient doctrine of vitalism.
An argument frequently used in support of vitalism concerns behaviour. A characteristic feature of living things is that they appear to behave in a purposive way, as though towards a specific end.
PAUL DAVIES. God and the New Physics. N.Y. – Simon & Schuster, Inc.,1984.
De acordo com o texto:
as formas superiores de vida caracterizam-se pela complexidade e organização.
o comportamento dos organismos biológicos é definido pela forma com que os átomos se organizam no interior das células.
a vida resulta pura e simplesmente de uma combinação química.
é possível obter vida a partir de átomos inanimados.
o comportamento das coisas vivas parece corroborar a doutrina do vitalismo.
