Viruses. Living, non-living, or alien?

[Veylon]

Viruses kind of sit in a gray area. There's a host of things that we look for in something that is alive: reproduction, active metabolism, genes, growth, etc. The thing about viruses, they only do some of those things and only a certain amount. Nature doesn't categorize; there's no hard line between living and nonliving like we want there to be and viruses are an awkward reminder of that.

 

[Twilight_guy]

They are not alive. A virus is basically a bit of DNA and a protein shell. There very weird freaks of nature. They are the robot Apocalypse of the micro-world.

 

[Lt.Snuffles]

I feel that it is silly to proclaim that something living can become a non-living being because it no longer seems to evolve. You can't exist as something not alive when you're made of living matter. Either it was always alive or never alive, and I vote alive.

The definition probably DOES need to be more flexible. A virus is certainly living enough to cause hell for human beings during its living process. It moves, it procreates, it eats, it responds to stimuli, and if it weren't still evolving then they would've been left in the dust by us humans instead of still infecting us.

Viruses don't eat, respond to stimuli, or move while outside the bloodstream. They are incapable of reproducing on their own, instead altering the DNA of other cells to tell those cells to produce more viruses. They have no metabolic functioning what so ever. They are not alive. The feeling like crap you get when you have some type of virus in your system? Mostly the result of your immune system not being happy about this foreign thing being there.

The Immune system is responsible for fevers and throwing up, and other symtoms designed to create a body which is not a suitable climate for a virus to survive/Occour. However the virus does cause some symtoms, for example rabies, the headache(I presume thats a symtom).
OT: I think that viruses are at the very edge of what can be described as life, as it does possess RNA. However I would probably categorize it under wierd chemical thing.
The Idea that they came seperatly from space is not too abstract, there is nothing like viruses on earth at all.

 

[King Toasty]

I feel that it is silly to proclaim that something living can become a non-living being because it no longer seems to evolve. You can't exist as something not alive when you're made of living matter. Either it was always alive or never alive, and I vote alive.

The definition probably DOES need to be more flexible. A virus is certainly living enough to cause hell for human beings during its living process. It moves, it procreates, it eats, it responds to stimuli, and if it weren't still evolving then they would've been left in the dust by us humans instead of still infecting us.

Viruses don't eat, respond to stimuli, or move while outside the bloodstream. They are incapable of reproducing on their own, instead altering the DNA of other cells to tell those cells to produce more viruses. They have no metabolic functioning what so ever. They are not alive. The feeling like crap you get when you have some type of virus in your system? Mostly the result of your immune system not being happy about this foreign thing being there.

The Immune system is responsible for fevers and throwing up, and other symtoms designed to create a body which is not a suitable climate for a virus to survive/Occour. However the virus does cause some symtoms, for example rabies, the headache(I presume thats a symtom).
OT: I think that viruses are at the very edge of what can be described as life, as it does possess RNA. However I would probably categorize it under wierd chemical thing.
The Idea that they came seperatly from space is not too abstract, there is nothing like viruses on earth at all.

HIV isn't just your immune system throwing a hissy-fit. It's more proof that a virus times and prepares for an attack. So yes, it's not too abstract to see these being from space. Perhaps, an entire planet of virus-like things, large and small- but my imagination gets ahead of me.

 

[Cain_Zeros]

I feel that it is silly to proclaim that something living can become a non-living being because it no longer seems to evolve. You can't exist as something not alive when you're made of living matter. Either it was always alive or never alive, and I vote alive.

The definition probably DOES need to be more flexible. A virus is certainly living enough to cause hell for human beings during its living process. It moves, it procreates, it eats, it responds to stimuli, and if it weren't still evolving then they would've been left in the dust by us humans instead of still infecting us.

Viruses don't eat, respond to stimuli, or move while outside the bloodstream. They are incapable of reproducing on their own, instead altering the DNA of other cells to tell those cells to produce more viruses. They have no metabolic functioning what so ever. They are not alive. The feeling like crap you get when you have some type of virus in your system? Mostly the result of your immune system not being happy about this foreign thing being there.

The Immune system is responsible for fevers and throwing up, and other symtoms designed to create a body which is not a suitable climate for a virus to survive/Occour. However the virus does cause some symtoms, for example rabies, the headache(I presume thats a symtom).

Oh, I'm not saying viruses themselves are harmless. They are, after all, changing the genetic make-up of your cells and eventually causing those cells to burst.

 

[zehydra]

Viruses don't exist as living things, but rather you can think of them as malignant strands of DNA that change the function of a living thing to help spread itself. Its DNA that exists for the spread of its own sake.

 

[Biosophilogical]

Viruses don't exist as living things, but rather you can think of them as malignant strands of DNA that change the function of a living thing to help spread itself. Its DNA that exists for the spread of its own sake.

Wouldn't that imply that our definition of life is narrow minded and cell-biased? I mean, isn't the general purpose of a cell and bodies and what-not to be a vessel for the continuation of the genetic material? Making viruses one of the most basic life forms possible, given that they are a protein shell and DNA?

 

[Dark_Yello]

How about we don't categorize it as alive or unalive but something else. As humans we have too few definitions and our views on everything is far to narrow. A virus should not be viewed as a noun but perhaps a verb. Virus's do things and act in ways we find strange and alien but only because we see them as one thing when they really are another.

Honestly this is more a philosophical question then anything because we cant simply say they're alive nor can we say they're not. Its possible to say a virus is a force of nature akin to an earthquake or hurricane. They are uncontrollable, unpreventable, and manifest themselves in the most unexpectable ways that leave the most brilliant minds dumbfounded.

 

[x EvilErmine x]

Viruses aren't alive any more than a prion is. Prions are self replicating protein molecules if you didn't know and they are responsible for CJD and Parkinson's disease in humans, Scrappy in sheep, and Mad Cow disease. The way they work is actualy by subverting similar proteins and converting them into copies of the prion. In this they are analogous to a virus subverting a host cells protein assembly functions.
Nether can replicate without assistance and neither possesses any sort of energy conversion mechanism (i.e no metabolism). They do not respond to external stimuli either, if you place a virus in a toxic environment it will not attempt to move away or protect it's self, nor will it actively seek new host cells. The way they survive is through truly staggering numbers and the laws of probability, nothing more.

One thing we do know about there origins though is that they must have been with us (us being life on earth) from if not the beginning, then very soon after it. All organisms on the planet are subject to infection by viruses. This indicates that they must have co-evolved with the earliest forms of life or they would not be present in all kingdoms of flora and fauna.

Another thing that would put them in the not life box (IMO) is the fact that they are surprisingly in efficient at replication. They are not good at reproducing there genetic code exactly, the rate of mutation is surprisingly high. The common cold virus on average mutates by about 1 base pare per year. This is the reason you cant develop immunity to it, it changes its glycoprotein structure (basically, the mechanism the body uses to identify self form non-self) too much and too fast for you immune system to recognise and destroy it straight away. This is an ingenious way of evolution without the need for sexual recombination but it's not really that good for the organism individually as the vast majority of the mutations will prove fatal, in so far as they dont just occur in the glycoprotein coding regions of the genetic material but all over. Meaning that there is a good chance that the mutation will be on a vital protein such as the one that allows the virus to attach the host cell or penetrate the cell membrane.

Slightly on a tangent...

Someone above mentioned that if we were to classify viruses as alive then we would also have to classify mitochondria and chloroplasts as alive too, well interestingly it seems as if this was exactly the case a long long long time ago. IIRC it looks like during the early evolution of life then the mitochondria and chloroplasts were indeed free living organisms that developed a symbiotic relationship with larger cells, these early cells were not very good at producing energy as they hadn't figured out how to use oxygen, the mitochondria/chloroplasts were good at energy production however because they had hit upon the idea of using this quite stupidly toxic gas to further the production of energy but finding food was a bit of a problem (lots of energy production = lots of fuel needed)....you can kinda see how a symbiosis might occur here cant you, eventually the two (three in plants, mitochondria, chloroplasts, and host) merged. It's indicated that this is probably what happened by the fact that the mitochondria still retains some genetic material within it's self. If they were not originally free roaming then there is no need for them to have this DNA.

One last thing without the humble virus it's very likely that we would not be here. Again IIRC.
The human genome project reveled that we all cary a viral genome that is encoded into our very DNA, chopped up into little pieces and made inactive by placing bit of junk DNA in between.
What the hell was it doing there? Well it turns out that it's actually quite important during pregnancy.
When a woman becomes pregnant and the baby begins to develop then it needs nourishment from the mother. This is done by the placenta. The placenta forms form the mothers own cells but also a few sperm get in on the act too and help out. This makes the developing placenta a hybrid between mothers cells and fathers cells, something that he mothers body would immediately reject and her immune system would attack on sight.
Now this is where the virus comes in, it appears that the placenta transcribes and expresses some of the proteins from the virus genome. Specifically the proteins some viruses use to mask them selves from the hosts immune system, this protects the placenta from attack and alows the bayby to develop. Without it the vast majoraty of pregnencys would self terminate and we would all never have exsisted im all probabilaty. Weard huh?

My god thats a lot of text....

Umm TLR then,

No i dont think viruses are alive.

 

[zehydra]

Viruses don't exist as living things, but rather you can think of them as malignant strands of DNA that change the function of a living thing to help spread itself. Its DNA that exists for the spread of its own sake.

Wouldn't that imply that our definition of life is narrow minded and cell-biased? I mean, isn't the general purpose of a cell and bodies and what-not to be a vessel for the continuation of the genetic material? Making viruses one of the most basic life forms possible, given that they are a protein shell and DNA?

Well that's the thing. Viruses technically are NOT the protein shell, just the DNA. The protein shell is the Phage that carries the virus, not the virus itself.

 

[zhoominator]

Depends how you define "living".

Many people think that if it doesn't respire, it isn't living. We respire, plants respire, even bacteria respire. Viruses don't however to my knowledge.

While they can replicate, they don't divide or anything like that. They are assembled using the resources of a cell, and I'd say that's more like a machine coming out. It is probably more like a piece of malicious software than a life-form.

I don't think I'd consider it life but kind of like a gateway to life (if that makes any sense).

 

[SuperCombustion]

They are non-living protien structures with DNA stuffed in there somewhere.
They're kinda like a machine programmed to assimilate cells.
in my opinion...

EDIT: what EvilErmine said

 

[thylasos]

Organic automatons. Spiteful parasites, deprived of life.

 

[Dags90]

Someone above mentioned that if we were to classify viruses as alive then we would also have to classify mitochondria and chloroplasts as alive too, well interestingly it seems as if this was exactly the case a long long long time ago. IIRC it looks like during the early evolution of life then the mitochondria and chloroplasts were indeed free living organisms that developed a symbiotic relationship with larger cells, these early cells were not very good at producing energy as they hadn't figured out how to use oxygen, the mitochondria/chloroplasts were good at energy production however because they had hit upon the idea of using this quite stupidly toxic gas to further the production of energy but finding food was a bit of a problem (lots of energy production = lots of fuel needed)....you can kinda see how a symbiosis might occur here cant you, eventually the two (three in plants, mitochondria, chloroplasts, and host) merged. It's indicated that this is probably what happened by the fact that the mitochondria still retains some genetic material within it's self. If they were not originally free roaming then there is no need for them to have this DNA.

While endosymbiosis is the leading proposed mechanism for the development of mitochondria and chloroplasts, the point I was trying to make was that mitochondria and chloroplasts are clearly not independent organisms any longer. It's the same reason we had to make Pluto an un-planet, if we accepted Pluto as a planet we'd have to accept a whole bunch of things that don't really make sense as planets. Except in this metaphor Pluto is viruses and the other bodies are viroids, mitochondria, plasmids, etc.

 

[oppp7]

I'm gonna go with living. They have DNA and reproduce, they react to their environment... so what if they are parasites? Or have cells?

 

[King Toasty]

HIV isn't just your immune system throwing a hissy-fit. It's more proof that a virus times and prepares for an attack. So yes, it's not too abstract to see these being from space. Perhaps, an entire planet of virus-like things, large and small- but my imagination gets ahead of me.

Wait-how does it 'time and prepare' for an attack? Never heard that before.

In the lysogenic cycle, they lay wait in a cells DNA for months, even years. Then every single infected cell will start the virus-reproduction process simultaneously. This is what happens with HIV.

 

[microhive]

HIV isn't just your immune system throwing a hissy-fit. It's more proof that a virus times and prepares for an attack. So yes, it's not too abstract to see these being from space. Perhaps, an entire planet of virus-like things, large and small- but my imagination gets ahead of me.

Wait-how does it 'time and prepare' for an attack? Never heard that before.

In the lysogenic cycle, they lay wait in a cells DNA for months, even years. Then every single infected cell will start the virus-reproduction process simultaneously. This is what happens with HIV.

When an outbreak occurs it is most likely due to a weakness on the host cell or the habitat of the host cell, previously unfit for production, has become better. Perhaps the bacteria coordination works here as well.

The theory of evolution doesn't contain any faults. It's a perfect working theory.

And just because an idea sounds fascinating or interesting that doesn't make it any more true unless you got evidence to back it up.

 

[Dags90]

In the lysogenic cycle, they lay wait in a cells DNA for months, even years. Then every single infected cell will start the virus-reproduction process simultaneously. This is what happens with HIV.

That's a gross misrepresentation of the lysogenic cycle. During a lysogenic cycle, which only a subset of viruses have, the virus remains dormant due to the conditions being inhospitable to replication. Then if the environment either becomes conducive to replication, or the cell becomes damaged, it will reenter the lytic cycle. There's more than one reason the virus may reenter the lytic cycle. One of them is that the virus, through a mechanism requiring further study, somehow know that the cell has become damaged and enters the lytic cycle to save itself from being stuck in a dead host.

You make it seem like some sort of cross host organized attack. It's not. It's not even well understood how they know whether or not the cell is damaged.