Viruses: Living or Non-living organisms

  • Thread starter Biosyn
  • Start date

Are viruses living or non-living organisms

  • Living

    Votes: 7 21.9%
  • Non-living

    Votes: 16 50.0%
  • Both

    Votes: 9 28.1%

  • Total voters
    32
  • #26
Pythagorean
Gold Member
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Interesting metric by Rosen. I can see how a virus would be an extreme by a particular metric; One point to keep in mind is that life probably won't be measured by the dimensionality of one variable, so while an extreme is hit in one dimension by viruses, the landscape across the whole n-dimensional space may have maxima at places other then the extrema of each abscissa.
 
  • #27
Pythagorean
Gold Member
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Probability?
Sorry, I missed the context of this. While probability is an important example, even deterministic models have behavior that eludes definitions. In stability analysis, we eventually have to ignore anything beyond first order terms if we want to move forward with conceptual discussion and theory. We can define the behavior for which the eigenvalues of a nonlinear system are positive (repellor) or negative (attractor). But we can't easily talk about what happens when one of the eigenvalues is 0, because those second order terms become important. For each system, we'd have to do the second order analysis (and if that's 0 too, we have to do third-order.. and if that's zero...) and for sufficiently high-dimensional systems, there will be no generalizing of the behavior.
 
  • #28
apeiron
Gold Member
2,013
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Interesting metric by Rosen. I can see how a virus would be an extreme by a particular metric; One point to keep in mind is that life probably won't be measured by the dimensionality of one variable, so while an extreme is hit in one dimension by viruses, the landscape across the whole n-dimensional space may have maxima at places other then the extrema of each abscissa.
Except it is explicitly a two variable model - a dichotomy. So you would have a pair of orthogonal axes. The virus might land entirely on the x-axis (or Replication axis), while an H2O molecule lands entirely on the y-axis (or Metabolism axis). Then living systems would have some co-ordinate on the plane created.

Instead of M-R, I might suggest we use entropy and meaning as purer descriptions. So a virus is all meaning (no entropy, just the constraints), while water is all entropy (no meaning, just the unconstrained material potential).

So a virus would be high in meaning, low if not zero in entropy measured in this two-variable space. Only a handful of base pairs can control a lot of cellular activity. And there is no wasted fat in information terms.

While water is maximally entropic on its own. Or within some cell, it then takes on a distinct temperature and pressure at least. It gains information by becoming part of a cell's organised metabolic economy.

On the other hand, your idea of an n-dimensional phase space doesn't capture the essential distinction Rosen was making. That would be just modelling a system's degrees of freedom, creating as many axes as you think there are degrees of freedom.

The systems approach is instead to measure both the degrees of freedom and their constraints. And Rosen was offering a maximally general model in terms of metabolism and replication, which I am suggesting becomes even more generalised as entropy and meaning.

I've got to say Rosen's scheme never stuck me as fully worked out. In fact, he called it metabolism-repair more than metabolism-replication. He also tried to make a strong connection to anticipation, his anticipatory systems papers. So his was a work in progress, and I'm now thinking that entropy-meaning (the kind of division now being made in biosemiosis) is sharper yet.

This means we still need a metric to define meaning. Another mathematical biologist who I believe is doing good work on this angle is Bob Ulanowicz - http://en.wikipedia.org/wiki/Ascendency
 
  • #29
fuzzyfelt
Gold Member
751
4
Sorry, I missed the context of this. While probability is an important example, even deterministic models have behavior that eludes definitions. In stability analysis, we eventually have to ignore anything beyond first order terms if we want to move forward with conceptual discussion and theory. We can define the behavior for which the eigenvalues of a nonlinear system are positive (repellor) or negative (attractor). But we can't easily talk about what happens when one of the eigenvalues is 0, because those second order terms become important. For each system, we'd have to do the second order analysis (and if that's 0 too, we have to do third-order.. and if that's zero...) and for sufficiently high-dimensional systems, there will be no generalizing of the behavior.
Thank you very much for replying, Pythagorean. I'm very sorry, I thought I had deleted the question, as I was thinking of a different one about subjective probability and multi-valued categories, but hadn't managed to do so, but thanks so much for your help.
 
  • #30
211
7
Perhaps we need a new classification that exists between life and non-life?
 
  • #31
113
0
Perhaps we need a new classification that exists between life and non-life?
Gene Creatures :biggrin:
 
  • #32
Viruses are of botanical and zoological enigma.There some facts which shows that they are living and some facts that they are non-living.This is the reason why diseases cause by viruses are difficult to treat the only remedial measure is using the vaccines.The viruses replicate in this respect this is one characteristic of a living thing that of reproduction.On the other hand viruses can be crystalised and kept in a bottle and close even for 300yrs but when release and found their substrate organ they start to replicate again this charactiristic is not in living organisms.Viruses do not respire,digest or excrete as living organisms do.
 
  • #33
Ryan_m_b
Staff Emeritus
Science Advisor
5,844
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There some facts which shows that they are living and some facts that they are non-living.
It's more a case of we don't have a definition that can adequately deal with viruses rather than us not having enough facts about them.
This is the reason why diseases cause by viruses are difficult to treat the only remedial measure is using the vaccines.
Vaccines are not the only measure and for some diseases there is no vaccine but there are treatments (like interferon or anti-retrovirals). I'm not sure what you mean by difficult to treat as I am unsure what you are comparing it to.
The viruses replicate in this respect this is one characteristic of a living thing that of reproduction.On the other hand viruses can be crystalised and kept in a bottle and close even for 300yrs but when release and found their substrate organ they start to replicate again this charactiristic is not in living organisms.Viruses do not respire,digest or excrete as living organisms do.
You can also put the component parts of viruses into a vial and they self assemble, in that respect they are complex biological nanoparticles capable of self assembly.
 
  • #34
418
0
The American Society of Microbiology states:

1. A virus is basically a tiny bundle of genetic material—either DNA or RNA—carried in a shell called the viral coat, or capsid, which is made up of bits of protein called capsomeres. Some viruses have an additional layer around this coat called an envelope. That's basically all there is to viruses.

2. Viruses are the simplest and tiniest of microbes; they can be as much as 10,000 times smaller than bacteria. Viruses consist of a small collection of genetic material (DNA or RNA) encased in a protective protein coat called a capsid. (Retroviruses are among the infectious particles that use RNA as their hereditary material. Probably the most famous retrovirus is human immunodeficiency virus, the cause of AIDS.) In some viruses, the capsid is covered by a viral envelope made of proteins, lipids and carbohydrates. The envelopes may be studded by spikes made of carbohydrates and proteins that help the virus particles attach to host cells. Outside of a host, viruses are inert, just mere microbial particles drifting aimlessly.

http://www.microbeworld.org/index.php?option=com_content&view=category&layout=blog&id=77&Itemid=72
 

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