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New Giant Viruses Further Blur the Definition of Life

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Re: New Giant Viruses Further Blur the Definition of Life

#21

Post by taneq »

meri_dian wrote: post #15

Here's a controversial view, but any good comments section needs a few of them: Viruses are no more "life" than bacteria are "life" or amoeba are "life" or ants are "life" or mice are "life" or humans are "life"... We're all just chemical machines, nothing more nothing less. Giving the word 'life' some special significance is misleading and confusing. In order to not confuse ourselves we should be talking about funct…

I thought this article was a very interesting take on the subject: https://blogs.scientificamerican.com/brainwaves/why-life-doe...

Re: New Giant Viruses Further Blur the Definition of Life

#23

Post by cobbzilla »

nyc111 wrote: post #19
ohf wrote: post #5

Earlier quoted context omitted.

Viruses are more like robots. They don't respond to stimuli. They just, do. The definition of "life" comes down to splitting hairs. We don't consider something "alive" if its behavior doesn't change when its environment does.

>We don't consider something "alive" if its behavior doesn't change when its environment does. I think this is too vague. A cat may continue to sleep without responding to changes in its environment but may respond to an internal stimulus (hunger) and get up and go. So response or lack of response to the environment may not be a good criterion to define life.

I think you're reading this too narrowly. The cat will respond to changes in its environment, even when sleeping. Try raising or lowering the temperature by an extreme amount while the cat is sleeping -- at some point it will awaken and seek a more comfortable place. To what extent does one need to change a virus's environment before it changes behavior? If its behavior is "fixed" by its genes and well understood, then there isn't much "dynamic" (complex) behavior being exhibited.

Re: New Giant Viruses Further Blur the Definition of Life

#24

Post by ibz »

nyc111 wrote: post #22

I consider legal entities such as corporations to be living organisms. So I don't agree that life is limited to organisms with a visible (biological) body.

Indeed! And they are made up of humans in the same way that biological bodies are made up of living cells.

Re: New Giant Viruses Further Blur the Definition of Life

#25

Post by emerged »

tensor_rank_0 wrote: post #3

anyone hear the theory that cytomegalovirus is a fragment of a gigantic prehistoric virus? a nurse friend heard about the theory in his medical microbiology class but I haven't been able to find much online.

d-d-dino virus? non-life finds a way.

Fascinating if true.

Re: New Giant Viruses Further Blur the Definition of Life

#26

Post by cobbzilla »

meri_dian wrote: post #15

Here's a controversial view, but any good comments section needs a few of them: Viruses are no more "life" than bacteria are "life" or amoeba are "life" or ants are "life" or mice are "life" or humans are "life"... We're all just chemical machines, nothing more nothing less. Giving the word 'life' some special significance is misleading and confusing. In order to not confuse ourselves we should be talking about funct…

One of the (many and oft-debated) aspects of life is that via homeostasis it maintains a negative entropy gradient. That is, over time, it will coalesce more "order" within itself than the 2nd Law of Thermodynamics says should normally happen -- more than if it were merely a random bag of chemicals.

I like this definition, because it implies some kind of "trying" -- life must "try" to keep some balance that continues its existence.

(a) Viruses (and certain bacteria) confound this approach because they can indefinitely continue (and even evolve) their existence without actively maintaining or improving any kind of this "balance"; they rely on their host to provide the balance, or at least some critical parts of it (if by definition, they cannot exist outside a host).

(b) Does this make them life? Unclear, maybe.

(c) Could such an organism evolve to no longer depend on a host? Yes, conceivable.

(d) Would this organism that maintains homeostasis on its own be considered life? I would venture to say yes.

So at what point during the evolution from (a) to (d) did this organism become "life"? It seems like it is just semantics at that point. Pick your criterion, call it life.

Re: New Giant Viruses Further Blur the Definition of Life

#27

Post by cobbzilla »

Synaesthesia wrote: post #17
meri_dian wrote: post #15

Here's a controversial view, but any good comments section needs a few of them: Viruses are no more "life" than bacteria are "life" or amoeba are "life" or ants are "life" or mice are "life" or humans are "life"... We're all just chemical machines, nothing more nothing less. Giving the word 'life' some special significance is misleading and confusing. In order to not confuse ourselves we should be talking about funct…

The problem with that analogy IMO is that machines can be comprehended by humans, whereas even the most primitive forms of life are more sophisticated than anything human created. Reproduction is an astonishing feat in itself - if only we could create a machine which could reproduce, but it's not so simple!

Reproduction is easy, and was done in software, on the Internet, in 1988 [1]. There is a lot more to life than mere replication, for example homeostasis. The Morris Worm did not make any efforts to maintain homeostasis, and thus became extinct relatively quickly.

[1] https://en.wikipedia.org/wiki/Morris_worm

Re: New Giant Viruses Further Blur the Definition of Life

#29

Post by SllX »

sebazzz wrote: post #4

I never understand why viruses are not life. Bacteria are life because they are essentially a single-cell organism and act like any cell in our body: they consume energy and produce waste. Viruses may not be a cell, but they can be damaged, they die, and they appear to be more than a simple chemical process.

Our understanding of life, viruses, and the relation between them is incomplete which means our definitions and lexicon as they are interrelated is also lacking in resolution.

Before the discovery of these Giant Viruses as I guess we are calling them now, you used to be able to make a useful distinction between cellular-based life, and viruses. Viruses were mere packets of information as far as our best understanding went with very simple mechanics. Cells are more complex, with a useful distinction being made between prokaryotes and eukaryotes when necessary, but each could be easily identified as being made up of one or more cells.

As our understanding of life improves, so does our useful observations into that murky grey area between life and not-life, and I suspect we will have to potentially extend the definition of life but come up with a vocabulary that more usefully delimits the forms it can take from its most simplest forms into the murkier grey area where viruses start to resemble cell-based life.

Science is a work in progress, and so must be the scientific lexicon. Consider further your use of the word "die" and is that really the word you would use when a virus expires? Maybe, if you consider them to be alive in the first place, but you might use the word "destroy" if you considered them to be more like an object, or at least not alive.

Re: New Giant Viruses Further Blur the Definition of Life

#30

Post by kitd »

nyc111 wrote: post #22

I consider legal entities such as corporations to be living organisms. So I don't agree that life is limited to organisms with a visible (biological) body.

While true in principle, natural organisms tend to be vastly more complex than even the largest corps, and complexity leads to emergent behaviour that you wouldn't see in a hierarchical human organisation.
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