Does life need water?

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Jesse

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Does life need water?
« on: 23/02/2010 09:30:02 »
Jesse asked the Naked Scientists:
   
Just want to say love the show been listening to it for 3 years and was wanting to know why life has to have water?  

Why cant other planets have life in a waterless  environment?

I know that life could be based on liquid methane, but what else could it come from?
 
Thanks

Jesse from Oregon

What do you think?
« Last Edit: 23/02/2010 09:30:02 by _system »

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Offline JimBob

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Does life need water?
« Reply #1 on: 26/02/2010 03:11:34 »
I would venture that it doesn't since there is some evidence that very simple life - RNA like organisms - existed before the earth had much of it. AND there are scientist who propose other life can be formed from silicon and sulfur, or other types of carbon compounds, such carbon sulfates.

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Offline LeeE

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Does life need water?
« Reply #2 on: 28/02/2010 11:51:10 »
I'm with JimBob on this.  While water is fundamental to all the life we're aware of here on Earth I don't see why it has to be a requirement for all life.  However, I'm very strongly inclined to think that some form of fluid is necessary for mobility, for if the molecules can't move relatively freely how are the the molecules going to get together to eventually form an organism?  A very interesting thought is the possibility of an organism forming in a super-cooled fluid environment e.g. a high He content gas giant that had been thrown out of its parent galaxy by a close-encounter gravity sling-shot event.

Well actually there is one other alternative: an organism could form in a zero gravity environment i.e. space, and as everyone knows, plenty of organic compounds have already been detected in deep space.

Oh, and I just remembered that there's been quite a bit of plausible speculation about 'life' forming in the atmospheres of gas giants.
...And its claws are as big as cups, and for some reason it's got a tremendous fear of stamps! And Mrs Doyle was telling me it's got magnets on its tail, so if you're made out of metal it can attach itself to you! And instead of a mouth it's got four arses!

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Offline chris

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Does life need water?
« Reply #3 on: 19/03/2010 21:44:59 »
So would we go so far as to say that water isn't essential for life?

It was always my view that this solvent was quite special, to the extent that it might be the one secret ingredient that makes like possible.

That said, in talking with Ben about this in the office the other day, he suggested that actually it's naive to believe that water would be so critical and that other solvents could work perfectly well - so long as an organism was suitably adapted to utilise them...

Chris
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Offline LeeE

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Does life need water?
« Reply #4 on: 19/03/2010 22:15:41 »
So would we go so far as to say that water isn't essential for life?

Tricky one.  I don't think the statement can be declared to be definitively true, for there is no evidence of life occurring without water.  However, we only have a single environment (effectively a single sample) to base any answer upon, which is clearly inadequate for any definitive answer.

I could only go as far to say that the statement is probably true. [;)]
...And its claws are as big as cups, and for some reason it's got a tremendous fear of stamps! And Mrs Doyle was telling me it's got magnets on its tail, so if you're made out of metal it can attach itself to you! And instead of a mouth it's got four arses!

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Offline chris

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Does life need water?
« Reply #5 on: 20/03/2010 09:20:39 »
Would we called a prion an example of life? I ask since, if you were to define prions as a life form - because they can replicate and they could mutate - then that sort of life form could exist in multiple environments so long as the protein is denatured and can interact successfully with new host proteins to copy itself...

I never forget a face, but in your case I'll make an exception - Groucho Marx

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Offline LeeE

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Does life need water?
« Reply #6 on: 20/03/2010 15:46:32 »
Talk of specific aspects of biology leads me rapidly out of my depth, but if prions can replicate and mutate then if they're not regarded as lifeforms they must be about as close as you can get, and a single mutation may be all that it might need to cross the dividing boundary.

I think they key is being able to interact: mobility would seem to be a prerequisite.  Fluid environments permit this, including fluids other than water, but see also my earlier mention of speculation (by others) about life forming in the atmospheres of gas giant planets, and even in space.
...And its claws are as big as cups, and for some reason it's got a tremendous fear of stamps! And Mrs Doyle was telling me it's got magnets on its tail, so if you're made out of metal it can attach itself to you! And instead of a mouth it's got four arses!

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Offline Samvolta

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Does life need water?
« Reply #7 on: 24/03/2010 15:55:21 »
I've heard of a possibility that an ammonia based life form is possible with liquid methane being its water equivalent in carbon based life. Uranus' moon Titan has scientists wondering whether or not rudimentary forms of such life has occurred in our solar system. Theory aside, it also depends on what definition of life you actually use. If life encompasses viruses/prions, then no not all terrestrial life requires water.