Originally posted by Jigtie
I'll admit I haven't read both links in their entirety, only the first few
pages of the first one, but it seems to confirm pretty much what I've
said.
Man, I must be stupid or something, 'cause I know you're not. Yet, you
seem to be implying that I'm basically wrong. 😕
Well, I'll just tip-toe back out of the science forum 'cause clearly this is
...[text shortened]... e. LOL! Nothing to see here. I'll be gone now. Spread
confusion somewhere else.
🙂
That explains it. The first paragraph on p.3 of the first article discusses the Mimivirus, apparently the largest virus known. Here's a quote from the article:
As the research team noted in its report in the journal Science, the enormous complexity of the Mimivirus’s genetic complement “challenges the established frontier between viruses and parasitic cellular organisms.”
http://www.sciam.com/article.cfm?id=are-viruses-alive-2004&page=3
There's is also a nice bit on p.2 where the discuss the idea of a continuum of life:
Another way to think about life is as an emergent property of a collection of certain nonliving things. Both life and consciousness are examples of emergent complex systems. They each require a critical level of complexity or interaction to achieve their respective states. A neuron by itself, or even in a network of nerves, is not conscious—whole brain complexity is needed. Yet even an intact human brain can be biologically alive but incapable of consciousness, or "brain-dead." Similarly, neither cellular nor viral individual genes or proteins are by themselves alive. The enucleated cell is akin to the state of being braindead, in that it lacks a full critical complexity. A virus, too, fails to reach a critical complexity. So life itself is an emergent, complex state, but it is made from the same fundamental, physical building blocks that constitute a virus. Approached from this perspective, viruses, though not fully alive, may be thought of as being more than inert matter: they verge on life.
http://www.sciam.com/article.cfm?id=are-viruses-alive-2004&page=2
The interesting part for me is the idea of the continuum of life. At present, there is no universal definition of "life". There is a conventional definition, but it's not as rigid as one would expect, with the consensus being "that life is a characteristic of organisms that exhibit all or most of the following phenomena:" which are listed as homeostasis, organization, metabolism, growth, adaptation, response to stimuli, and reproduction.
http://en.wikipedia.org/wiki/Life#Definitions
However, if there's no strict definition of life, then how can organisms be definitely classified? As mentioned by you and others elsewhere in this thread, traditionally viruses are not considered alive while bacteria are (since 1935, according to the first article), although bacteria like Rickettsia and Chlamydia and the Mimivirus blur the lines:
http://en.wikipedia.org/wiki/Rickettsia
http://en.wikipedia.org/wiki/Chlamydia_(bacterium)
http://en.wikipedia.org/wiki/Mimivirus
I suppose the debate really isn't about whether viruses are living or non-living in a dichotomic sense, but about whether a sharp dividing line between living and non-living things even makes sense.
26 Dec '08 23:58
Embarrassed at a Party
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