Are Viruses Considered As 'alive' Following up on the robots-life issue

[webintern 0]

The controversial debate about whether viruses are living organisms or not has gone on for decades. One side claims that viruses undergo a reproductive cycle that is analogous to that of the more classical lifeforms. The other side claims that viruses do not possess other fundamental processes that characterize life, such as respiration, digestion, etc. I suppose the true answer lies on one's particular definition of the word "life". This is similar to the debate among astronomers on whether Pluto is a planet or not (at the moment it is).I personally would not consider viruses to be living organisms. If you deconstruct the virus, you will merely find one or more strands of nucleic acids (DNA or RNA), a capsid, some rudimentary proteins, and in some cases, a viral envelope. Beyond possessing the machinery to replicate within the host, it does not have any intrinsic mechanism to seek additional hosts. Contrast this to the bacterium, which may chemotactically move toward greater concentrations of nutritients.Moreover, if we were to call viruses living organisms, then what about prions? They are mere proteins that fulfill basic replicative functions. Otherwise, they have nothing else that exhibits any semblance of life. So are they "alive"?

[Arbitrary 0]

I personally would not consider viruses to be living organisms. If you deconstruct the virus, you will merely find one or more strands of nucleic acids (DNA or RNA), a capsid, some rudimentary proteins, and in some cases, a viral envelope. Beyond possessing the machinery to replicate within the host, it does not have any intrinsic mechanism to seek additional hosts. Contrast this to the bacterium, which may chemotactically move toward greater concentrations of nutritients.

Yet, why do scientists get to define life? I mean, they decide that a living organism must contain 1), 2), and 3), but why? That's only a very abstract decision on their part to categorize things into groups. There was no inherent definition that one thing was "living" and another was "non-living". Although I suppose you could argue that by getting rid of that definition, it's almost impossible to have any standards to go by at all....
Though, according to the current definition of life as quoted by the scientists, then yes, I too agree that viruses are not alive, as webintern stated very well.
Edited August 20, 2006 by Arbitrary (see edit history)

[yeh 0]

Yet, why do scientists get to define life? I mean, they decide that a living organism must contain 1), 2), and 3), but why? That's only a very abstract decision on their part to categorize things into groups. There was no inherent definition that one thing was "living" and another was "non-living". Although I suppose you could argue that by getting rid of that definition, it's almost impossible to have any standards to go by at all....

That is a very good point by Arbitrary. On one side we have the definition of "life" as defined by a group of scientists. On the other side, "life" is just ... well, life. Ok, I might not be getting my point across but what I'm trying to say is the semantic problem associated with common terms. We use those terms thinking that it is universal but most of the time, the terms meant different things to different people.

[Xisle 0]

As far as I'm concerned... viruses are not considered alive, they are just a group of chemicals... I'm not a science genius or anything, but according to my Biology class a couple years ago.. they're not alive.I thought alot about it too...

[toby 0]

Ah ha! But how can something "die off" if it is not "alive?" I remember kindergarten when we used to talk about what was alive and what was not... or maybe it was on TV, the two kind of blend together. If it moves, eats, and breathes it's alive... But of course there are exceptions... Like some politicians, but that's another topic

It's a cell that can exist out of an orgasism or tissue with others.

Viruses and the like fit that Mrs (thingy) that are the signs of life, I've seen them (not my microscope).

[nighthawk1405241531 0]

This is very difficult question. They look more like very complicated chemical than a living being. And those things that cause mad cow disease ( I forgot how they are called) they don't even have DNA nor RNA. They are consisted only of proteins, so we can treat them more like a poison. But they are able to multiply inside host's body.It's really hard to define what is alive and what is not. And what would happen when we build a robot that has all properties of a living being (take care of itself, multiply...). Would it be alive?

[Chesso 0]

nighthawk, that's actually a pretty good point about robots, I suppose more people would be leaning on the no in regards to that though (but it may very well end up on the debate table aswell).I do not have any knowledge or any sort of education concerning biology or anything like that so anything I say is purely based on my logical thoughts or some such eh.I'm not entirely sure how a virus or other similar things work but if it can manage to feed off something and replicate itself and grow and what not I would say it's alive.Maybe not in the same was as us, bit I suppose if you think about, it does have some similarities eh.In regards to "vegetable people", I would classify them as alive, their brain may not function as well but their overall system still caters to iself to a degree and grows, changes, eats, excretes etc.Anyway, I don't have any technicaly knowledge on the subject so I can't say much, but from my understanding I would classify a virus or some virus's as alive.

[webintern 0]

Just a few technicalities ... prions, which are the proteins mentioned earlier that cause Mad Cow's Disease (BSE or bovine spongiform encephalopathy), do not actually multiply in the traditional sense. That is, they do not take raw products and transform them into replicants of the original. Instead, they convert already existing proteins to conform to their shape. The resulting protein then has the same replicative (or transforming) properties as the original protein.As for chesso's ideas, they are pretty good considering your lack of background in biology. But for accuracy's sake, viruses do not "feed off something". They simply utilize your body's cellular machinery to produce DNA or RNA and proteins that become new viruses. The fundamental processes involved are virtually identical to that used in cells.

[Chesso 0]

Thanks for the nice comment webintern, it's greatly appreciated!So if I have this right now, say these cells within the body are generated, more or less by the body and these virus's simply transform or in some way change them to be like the virus, is that along the right lines?Seeing more discussions such as this on the board are really starting to peak more of an interest in them for me, I may have to start doing some searching and self learning to find some more technical details and understanding so I can participate better in discussions like these.

[mitchellmckain 0]

The definition of life is too long to post here, check it out on the link. Why is this definition so long? It's easy: exceptions. Our planet houses such a biodiversity that everytime they make an all-included definition, a (new) species pops up from which we're sure it's an animal, but misses one key in the chain that makes it life. In order to make a correct definition it expands everytime, again and again.

the symptoms of life. If a supposed organism shows these signs, it's alive. So they say.

This definition of life is typical of Biology as an observational rather than theoretical science much like Astronomy which simply looks at what is out there, classifies them, and tries to understand them. The problem is that there no way to identify what features are merely indicental characteristics of life on this planet only.

But chaotic dynamics provides the mathematical foundations for a more theoretical definition of life as a particular kind of cyclical process which forms a kind of feedback loop that reinforces its own structure. It has been observed that such processes have the capacity to react to changes in the environment in a phenomena that resembles choosing called bifurcation which can lead to increasing diversity and complexity. The problem is that instead of making a sharp line between what is alive and what is not, instead it suggests more of a quantitative continuum from the less alive to the more alive. As a result, it should be of no surprise that according to this more theoretical definition viruses are definitely alive even though the quantitative measure of this life would be very low indeed. Its dependence on other life forms, although more extreme than most other life forms, is not unique, since in fact most life forms depend critically on the existence of other life forms.

[webintern 0]

So if I have this right now, say these cells within the body are generated, more or less by the body and these virus's simply transform or in some way change them to be like the virus, is that along the right lines?

I'm sorry if I had confused you. The phenomenon you describe above is more appropriate to prions, which transform other related proteins to become like them. Think of it like cult brainwashing. Each cult member brainwashes a victim to think and act similarly as the original member. Consequently, the victim transforms into another brainwasher who then seeks other victims. The concept of prions is virtually identical.

Viruses, on the other hand, are like parasites that enter the cell and exploit the cellular machinery for its own devious purposes: creating components to build new viruses. To put the scales into perspectives, let us for fun say that the cell is an automobile factory and the virus is Megatron (the Decepticon Transformer). Megatron cannot transform (excuse the pun) the factory into another Megatron. He, however, invades the factory and uses the machinery to create more Decepticons. This is analogous to how viruses invade and replicate within the cell.

The dilemma about viruses being considered as lifeforms, however, is that these viruses do not purposefully manipulate the cell by will or foreknowledge. Bacteria have receptors that help it identify where there are increasing gradients of nutrients. Viruses just "float" around until it accidentally "bumps" into a cell. If an interaction exists whereby the virus can enter the cell, it does; otherwise, it continues to "float" around. The individual virus does not mutate or adapt to unfavorable conditions. Viruses merely exist and replicate as a result of serial biochemical reactions. In the same way, computer viruses have a predefined pattern of invasion and replication. It is not a misnomer to call them viruses, because their existance and interactions are very similar to that of biologic viruses. So, this begs the question, are computer viruses alive?


My above points are not meant to serve as arguments in favor or against viruses being considered living organisms. They are merely intended to be food for thought. So, please don't start deconstructing my statements, because they are not meant to be points of debate.

[Eternal_Bliss 0]

The problem is with ourselves. We humans want to clarify all the things in this infinite Universe with our limited and arbitary approach. The approach which suits our purpose best,but which need not be correct. So there is no surprise that we find problem in classifing many of the things. As humans are also only a part of this huge framework called Universe. Though we are capable of logical reasoning unlike the animals we are not the masters of the Universe.

[Chesso 0]

What about Jellyfish? I'm not an expert but recent things (for some reason I remember) told me basicalyl that's what jellyfish also do.They have no control over where they go and what they do, they have no form of brain or anything like that.I'm pretty they are considered alive, errr are their behaviours and restrictions closely related?

[webintern 0]

True, jellyfish may not have "brains" in the traditional sense. Bacteria and fungi do not have brains either.Jellyfish still have a nervous system. They need food to survive, have for sexual reproduction (not that sexual differentiation is a criterion for being considered a living organism), possess limited mobility and defense mechanisms that react to its environment, etc.

[Chesso 0]

But basically the enviroment has the largest impact, a jelly fish can't even move of it's own free will..... it's enviroment chooses where it goes and ultimately what it does.Sounds a bit like this virus in a way eh?Besides the uhhh obvious more technical difference between them.