Viral Life

[Velocity517]

Yeah, I know I'm prolly beating a dead horse with a stick here, but i was just wondering if there was anything new on the "Are virus' actually living?" debate....? I'm trying to learn about biology/microbiology, but I'm not very deep in if you know what I mean.

[insane_alien]

theres nothing really new on it.

 

although, they have been synthesised through chemical processes.there was something in 'new scientist' a while back about it.

 

personally, i think they are just molecules with some interesting biological effects. then again, i define biology as 'the study of carbon compunds that wiggle'

[Cyanide]

You know that always interested me, since like 7th grade..

They still don't know.

Since viruses do not fit all of the criteria..

But scientists have changed several definitions over the years..

look how they just modified the definition of "planet"

 

I just completed a biology lab where we looked at DNA from bacteriophage lambda..really neat

[Sisyphus]

You know that always interested me, since like 7th grade..

They still don't know.

 

It exhibits some but not all of the characteristics by which "life" is defined. It's not that they "don't know." It doesn't meet the characteristics, so it is not alive. That's all that "being alive" means. Just like, as you say, with planets - it's not that they "discovered" that Pluto isn't actually a planet. They just changed the definition, and Pluto no longer fit.

[Bluenoise]

Viruses are very well understood. I mean "very very well" understood. The question of are they alive isn't one of science and discovery. It is a philosophical question, that partially depends on the definition of the word alive.

 

Thus it's not an issue of "they don't know" it's an issue of coming to an agreement of the definition of life that we all can agree on.

 

They question is a matter of semantics left to philosophers and linguists. Not science.

[SkepticLance]

As bluenoise said, it is a matter of definition, and you can choose your definition to suit the answer you want.

 

Sisyphus said they are not alive since they do not meet all the criteria of 'life'. Sadly for this statement, there is no universal agreement on what are the criteria of life. My own belief is that there are only two.

 

1. Biological reproduction.

2. Biological evolution.

 

Most of the traditional criteria for life, such as growth, nutrition, excretion, reproduction etc are met by a forest fire. But it does not evolve.

 

My two criteria are considered inadequate by many biologists who point out that certain computer programs both show elements within the program that reproduce and evolve. Thus, the nearest widely accepted definition of life goes something like this :

 

" Life is a complex system of organic molecules that reproduce their unique patterns from generation to generation, and evolve into other complex patterns over time."

 

Those who want to exclude viruses add to the definition some statement that the reproduction is autonomous - not dependent on other life.

 

Personally, I am not sure that a computer program cannot be said to be 'alive'. And I think viruses must be considered to be alive. But that is just my opinion.

[Airmid]

Like others in this thread said, there's not one definition for Life.

 

I think the most generally applicable definition that is in use at the moment, is NASA's: a ‘chemical system capable of Darwinian evolution’. This is the definition that Astrobiologists commonly use when considering life on other planets. Virusses fit this definition. Crystals, however, do not. Crystals are able to self-replicate, and even introduce tiny errors in "child-crystals", but the errors are not inherited, and therefore crystals are not capable of Darwinian evolution.

 

To anyone who is interested in defining life and astrobiology, this fairly recent review article is a darn good read!

 

Airmid.