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Originally posted by: DanielB
Shimraa, you're talking about things that don't exist, and there's no evidence of them existing either. You're right, the fundamental form of life is the cell. Even ignoring that, a virus does not perform the necessary functions of life. It is a non-living thing. It performs operations out of necessity only.
Anyhow, I’ll explain, if I must, to you why such a virus could not exist. Because it wouldn't be able to reproduce, end-of-story. If it fused with a cell, then it can't infect other cells, it can't spread. I find the idea of a single cell's DNA changing effecting the whole completely ludicrous.
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Anyway viruses are not, by the current definition of life, alive. (Correct). However they have many, not all, but many characteristics of life. they 'evolve'; that is why you have a different form of influenza every year, (yes) they feed, once they are in a cell NO. (They don’t feed. They use the cell’s machinery (Transcription and Translation) to produce more viral particles), the virus will use the food the cell makes to replicate (actually they use the cell’s energy molecules such as glucose as a source of energy to be able to accomplish their goal of producing more viral particles). Parasites which are a form of life follow this exact same proccess, (correct) however they are made up of cells and most can break down very simple forms of food. they still require there host to provide all these things though. they are like larger living examples viruses. you are incorrect in saying that viruses cannot survive without a cell. this is true from some viruses like HIV however it is not true for others which will remain intacte for long peroids of time outside of a cell (you are correct. Some viruses can survive for long periods outside of a cell). and you stated that a cell can survive without the virus, once a cell has been infected it cant survive without the virus. the reason viruses are not defined as life is because by definition the fundimental form of life is the cell, and since viruses are not made up of cells the can't be called life even if they fill many of the other requirements, that is why viruses are not defined as living. (Remember viruses don’t grow nor do they respire, two characteristics generally associated with living cells). IF this definition were changed which can happen very easily then viruses could be called life. there is a push in the world of science now to change this definition,(true – my personal opinion is that the definition does need to change). these scientists propose that nucleic acids should be defined as the fundimental form of life. however, that is beside the point when i said that viruses could have been involved in evolution the theory ( - current thought is that they have been interlinked in evolution for a long time). spans from the fact that viruses can substantially change the DNA make up of a cell, it could be possible that at some point in the past there was a virus which would fuse itself with the cells DNA rather then take full control of the cell it would become a part of the cell and change it, in this way when the cell reproduced it would create a much different form of life. so even thou viruses are not currently defined as life they still could have affected evolution in the method decribed above. (True, therefore the argument goes that if they have affected evolution in such a way, which is very plausible, then we need to rethink the definition of life.)
Hope this helps.
Call me when you’re in town.
ok what i have posted above was my post which was critiqued by a biologist that i know this is done by am man that knows alot moreabout this then both of us. the process of viruses in evolution are very complicated he added to me. i will not begin to explain that to you because frankly i do not know much about them however besides the point, it is still 'very plausible' that virus were part of evolution. the mechanism that i used to explain it is correct but only just it is a very very simple way of explaining it.