The definition of what constitutes a living thing is not as cut and dried as many would think. If we define a living thing as something that takes materials from its environment , consumes them to make energy and reproduce themselves, and then excretes waste...then stars are alive and most chemical reactions can also said to be living ones, so how do we distinguish what we familiarly call "life" from ordinary chemical processes. Can we add in the restriction that the interactions must be performed by multicellular organisms to be alive then we have just removed many types of archaic bacteria and viruses from the category of "life" and we know that these organisms are capable of reproducing themselves. Maybe the problem is the question, maybe we have used a much too narrow definition of "life", I propose that instead of defining life in terms of resource utilization and reproduction that we define it in terms of one thing that life does that non life does not. Life has the unique ability to continue to change despite the fact that the required resources for its survival do not, this is the result of the nearly random effects of mutation. All cells are subject to mutation by virtue of their existence on a planet, near a highly radiating Sun. The effects of UV radiation on our cells introduces mutations in the genetic structure of even the smallest organisms and changes over time how those organisms relate to the outside environment. In the billions of years that have elapsed since the first signs of life on Earth, mutation has played its part in the development of increasingly more complex systems from blind chemical processes. The formation of the cell wall is said to arise from the combination of having simple replication molecules trapped insides lipid bodies which naturally, in their mindless acquiesence to conservation of energy, form into spherical shapes. The process of genetic transcription also occurs from the blind chemistry of the simple sugars which are themselves nothing more than energy conservative combinations of elemental molecules like Nitrogen, Oxygen, Carbon and Hydrogen which have known (but probabilistically certain) affinities for bonding and attraction.
In living systems contrary to those of low level chemical systems (reactions) the failure of elements to bond is expressed as an improbability of the occurance coupled with the brevity of the survival of the new species (the atomic scientists word ...not mine!) what is not energy conservative ceases to exist after brief periods. Life on the otherhand persists through mutations and macroscopically results in a materially different system that can then propagate its particular mutation set to its progeny. Viruses do this, the most archaic Bacteria do this, plants and people do this. Stars do not do this, snow flakes do not do this, a catalyzing reaction between two elements or more complex chemicals does not do this. The evolution of what I propose as non life is rigid and fixed once the energy regime for a reaction is set, once oxygen and hydrogen meet under the right temperature and pressure constraints water WILL form. Abberant species of hydrogen/oxygen molecules are probabilistically denied to exist for any important (meaning allowing continued reaction) duration. Similarly, stars are not alive because they do not have the ability to continue their stellar burning beyond the limits of their acquired Hydrogen fuel, the initial mass value or addition of new material does lead to a change in the evolutionary trajectory of the star (will it be a white dwarf? a neutron star or a black hole? or will it go NOVA?) but these changes are precisely predicted ones. Unlike true life, who's evolved state under mutation holds the possibility for highly unpredictable changes in the final entity, particularly after generations of mutation and propagation.
So formerly my proposal for a new definition of "life" is:
Life, any entity that under the process of internal random mutation changes how it interacts with the outside environment from generation to generation despite having at any given moment the resources (even if fixed in quantity) required for its survival.
How's that?
In living systems contrary to those of low level chemical systems (reactions) the failure of elements to bond is expressed as an improbability of the occurance coupled with the brevity of the survival of the new species (the atomic scientists word ...not mine!) what is not energy conservative ceases to exist after brief periods. Life on the otherhand persists through mutations and macroscopically results in a materially different system that can then propagate its particular mutation set to its progeny. Viruses do this, the most archaic Bacteria do this, plants and people do this. Stars do not do this, snow flakes do not do this, a catalyzing reaction between two elements or more complex chemicals does not do this. The evolution of what I propose as non life is rigid and fixed once the energy regime for a reaction is set, once oxygen and hydrogen meet under the right temperature and pressure constraints water WILL form. Abberant species of hydrogen/oxygen molecules are probabilistically denied to exist for any important (meaning allowing continued reaction) duration. Similarly, stars are not alive because they do not have the ability to continue their stellar burning beyond the limits of their acquired Hydrogen fuel, the initial mass value or addition of new material does lead to a change in the evolutionary trajectory of the star (will it be a white dwarf? a neutron star or a black hole? or will it go NOVA?) but these changes are precisely predicted ones. Unlike true life, who's evolved state under mutation holds the possibility for highly unpredictable changes in the final entity, particularly after generations of mutation and propagation.
So formerly my proposal for a new definition of "life" is:
Life, any entity that under the process of internal random mutation changes how it interacts with the outside environment from generation to generation despite having at any given moment the resources (even if fixed in quantity) required for its survival.
How's that?
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