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The definition for life


Genecks
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What qualifies something as living?

Should we as scientists consider something as living?

Is this a term that has psychological attachment?

If so, should we abandon it?

 

I will set forth the idea that everything is dead.

Nothing can be defined as living; and nothing should be defined as living.

Atoms and molecules are not living.

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I'll take a shot: "Life" is the term for a self-contained biological system that is still functioning and has metabolic activity. A live organism is composed of individual mostly live parts.

 

Isn't that a tad tautological? 'living' is part of the definition of 'biological', and if a living organism is made of living parts, then what's the definition of 'living part'?

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This is what wikipedia says about live, in biological terms

 

"Since there is no unequivocal definition of life, the current understanding is descriptive, where life is a 'characteristic' of organisms that exhibit all or most of the following phenomena:[16][17][18]

 

Homeostasis: Regulation of the internal environment to maintain a constant state; for example, electrolyte concentration or sweating to reduce temperature.

 

Organization: Being structurally composed of one or more cells, which are the basic units of life.

 

Metabolism: Transformation of energy by converting chemicals and energy into cellular components (anabolism) and decomposing organic matter (catabolism). Living things require energy to maintain internal organization (homeostasis) and to produce the other phenomena associated with life.

 

Growth: Maintenance of a higher rate of anabolism than catabolism. A growing organism increases in size in all of its parts, rather than simply accumulating matter.

 

Adaptation: The ability to change over a period of time in response to the environment. This ability is fundamental to the process of evolution and is determined by the organism's heredity as well as the composition of metabolized substances, and external factors present.

 

Response to stimuli: A response can take many forms, from the contraction of a unicellular organism to external chemicals, to complex reactions involving all the senses of multicellular organisms. A response is often expressed by motion, for example, the leaves of a plant turning toward the sun (phototropism) and by chemotaxis.

 

Reproduction: The ability to produce new individual organisms, either asexually from a single parent organism, or sexually from two parent organisms."

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This question pops up every now and then. The basic is that there is no consensus, only more or less useful conventions that assist in categorizing stuff. Whether it is useful to make such a distinction in the first place is dependent on the question at hand.

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This question pops up every now and then. The basic is that there is no consensus, only more or less useful conventions that assist in categorizing stuff. Whether it is useful to make such a distinction in the first place is dependent on the question at hand.

 

I figured that someone might make such a statement.

As said before, should we as scientists consider something as living?

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Genecks, I have no idea what you are talking about. I am talking from the perspective of a scientist. A distinction only makes sense if it is helpful in any way or if it is based on intrinsic properties. The dichotomy between alive and dead is very old, however, we know that there is no clear cut distinction. Viruses are definitely borderline, for instance. If we consider metabolism to be crucial, they are definitely not. However, as biologically active replicative entities they cannot be dismissed as pieces of dirt, for instance. How about differentiated cells that lack the ability to replicate, for instance?

In other words, in science the question is far from trivial, yet making the distinction makes sense in certain contexts, and doesn't in many other. It is more a convenience, similar to the species concepts (although the latter of a higher impact in many fields), to make that context depending distinction.

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Genecks, I have no idea what you are talking about. I am talking from the perspective of a scientist. A distinction only makes sense if it is helpful in any way or if it is based on intrinsic properties. The dichotomy between alive and dead is very old, however, we know that there is no clear cut distinction. Viruses are definitely borderline, for instance. If we consider metabolism to be crucial, they are definitely not. However, as biologically active replicative entities they cannot be dismissed as pieces of dirt, for instance. How about differentiated cells that lack the ability to replicate, for instance?

In other words, in science the question is far from trivial, yet making the distinction makes sense in certain contexts, and doesn't in many other. It is more a convenience, similar to the species concepts (although the latter of a higher impact in many fields), to make that context depending distinction.

 

Well said, and much agreed, and my 400th post :doh:

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