What exactly is a virus and how does it work?
Computer or disease-causing?
there is a real philosophical debate brewing about whether there is any distinction between a computer and a biological virus.
A bio-virus is an encapsulated strand of DNA that invades a cell, edits the programming code of the cell, and uses the cell’s resources to reproduce themselves.
A computer virus operates essentially identically in an environment of electrical fields within a computer.
Some say computer viruses are the first human created life. Others say that bio-viruses themselves are not “alive” as we understand it (at least outside of a host cell), and so neither are computer viruses. But even that opinion shows the closeness of the two conceptually.
I say, shoot 'em all and let God sort 'em out.
That is so weird. Why are they here, then? What is their evolutionary history? Is it one of those “Selfish Gene” thing? Maybe they are aliens?
But my main question is - how did they come about and why?
Also, sorry for the hijack. It is kind of only a semi-hijack, though?
It is not that weird, as no one has a consensus on what the definition of “life” is. One definition that is often bandied about is that living organisms possess five qualities at a minimum:
- obtain and utilize energy
- growth and development
- respond to stimuli
- produce waste
- reproduce
(I believe those are correct. I’m doing this from memory. Someone will, I hope, correct any mistakes.)
Viruses, on their own outside a cell, do not do any of these, so are argued by some not to be alive. Of course, this is not a perfect definition of life, as fire seems to meet these qualifications, and most would not consider it alive.
It is doubtful that they are aliens, as the “code” they use to translate nucleic acids into amino acids is the same as for any other life on earth. It is not immediately apparent that this would be so in an alien organism, assuming they even used nucleic and amino acids.
As for how they came about, no one really knows. Perhaps they were originally bacteria (or predecessors of bacteria) that evolved to simpler and simpler structures until they became as simple as possible. Maybe they were ribosomes, or some other piece of RNA or DNA that was faulty, yet had the ability to reproduce itself. After that, its a simple matter of time and evolution. Perhaps they are continually arising from fragments of DNA that have those abilities.
No one knows how long they’ve been around, either. Viruses don’t leave very good fossils. It seems reasonable, however, that they’ve been around pretty much as long as there’s been “higher” life to parasitise.
-b
Transposons are segments of DNA that will detach themselves from the genome and relocate to a different site in the same genome. One theory is that viruses originated when a transposon just kept going and left the cell. Eventually viruses developed protective protein coats and evolution caused the diversity we see today.
A previous thread related to this discussion can be found here.
How Stuff Works has several pages on this. Might be worth a look.
For those interested How Stuff Works also has a bit on how computer viruses work as well.
I have heard it suggested that viruses are the real motivators behind evolution. Left to its own devices organisms may evolve slowly over millenia but occasionally a virus will speed the process along considerably. I’ll grant that most have ill effects on the host organism but once in a long while a virus might benefit the organism. That doesn’t say anything about how they came about and that might not even be correct (from a vague memory of mine) but maybe someone else can shed light on this.