Why does life need water specifically?

Discussion in 'Biology & Genetics' started by leifanator, Dec 8, 2011.

  1. leifanator Registered Senior Member

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    I'm curious about what makes specifically water more suitable for life than other liquids. ie; why can't life survive in methane, or ethanol?
     
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  3. Robittybob1 Banned Banned

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    Just to set the ball rolling , but not in the right direction, we used to say, "how much blood do you have in your alcohol system?"
    Some people have more alcohol than water in their blood.

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  5. Robittybob1 Banned Banned

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    They tell me there is a bacterium which can live in diesel fuel. Now that is extreme! I have not got a lead to it.

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    http://www.dieselsolutions.co.nz/the-diesel-bug.shtml
    Evidence of the "bugs"
    Virtually all fuel has some bacteria life however it may not be that apparent to the naked eye. These microbes start off as small microscopic single, separate living cells. At this point, they can pass though any size filter medium, and injector nozzles. However, their growth can be very rapid. Given the right conditions, a single cell weighing one millionth of a gram can grow into a bio-mass of slimy algae mats weighing 10 kilograms within twenty four hours. By the time you can visually see evidence of growth, the infestation problem is quite severe. Not all growth happens so suddenly. In some situations, growth occurs slowly, creating problems during development.
     
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  7. Aqueous Id flat Earth skeptic Valued Senior Member

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    For one thing, Water hydrolyzes materials used by cells.


    For another, life apparently sprang from the primordial soup of water and other stuff. The fundamental cellular design is centered around transport of materials in and out of the cell membrane through osmosis. It stands to reason that once this trait was established, it became the root of nearly all higher life forms.

    There are some exceptions, another trait which succeeded in the independent domain Archaea.

    Extant examples include certain life forms that can thrive in abormal conditions, such as the boiling acid vents from the Yellowstone calderas:


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    Obviously water is still important, but in a very different sense than implied i the question.
     
  8. cosmictraveler Be kind to yourself always. Valued Senior Member

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    I know of many who survive on alcohol!

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    :cheers:
     
  9. Pincho Paxton Banned Banned

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    Personally, I think that one main things about water is that it aids in the ability to overcome gravity. So it is easier to grow upwards against the flow of gravity. Apart from that, it is probably a state of energy that is less destructive than most other forms of energy.
     
  10. elte Valued Senior Member

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    "Why does life need water specifically? "

    I'd say because life, as we know it, evolved using water.
     
  11. C C Consular Corps - "the backbone of diplomacy" Valued Senior Member

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    Microscopic life certainly isn't ruled out on Titan, so one might ask why complex life seems to favor a water world. Or at least something better than just a different chemistry counterpart of slime mold struggling on frigid moons and planets.

    A dominating presence of water found in conjunction with complex life could be coincidental -- a consequence often accompanying a warm and stable world (possibly) necessary for the emergence and prospering of such a class of biotic entities. With the latter accordingly capitalizing on this abundant resource and developing an iron-clad dependency that might seem to observers to have been there from the very start, with no optional route even available.

    But water is a better solvent compared to some other potential substitutes, like methane. While hydrocarbon lakes and oceans actually need extreme cold, the latter surely wouldn't assist much in a speedy development and evolution of organisms into highly organized bodies, or overcoming sluggish internal rates of activity and potentially frequent retreats into dormancy.
     
  12. Captain Kremmen All aboard, me Hearties! Valued Senior Member

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    Water is a solvent that is Ph neutral and not very reactive.
    It is liquid at normal temperatures, so that the reactions you want to occur can take place fairly quickly
    There is also a lot of it around.
    It is a perfect medium for chemicals to move around in, and react without interference.

    I probably haven't given half the qualities which make liquid water the best fluid for life to thrive in.

    One fortuitous thing is that it expands and floats when frozen. If it didn't, ice would never melt in summer, and eventually nearly all water on Earth would be frozen.
     
    Last edited: Dec 8, 2011
  13. arauca Banned Banned

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    If hand water is a polar solvent , a polar solvent dissolves ionic compounds.
    Ionic compounds conduct electricity , In an aqueous media separation of organic compounds is possible to make electrical barrier in order to have charge potential for electrical signals
     
  14. Robittybob1 Banned Banned

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    Is this important right down to a single cell level? Do bacteria need charge potentials as well?
    I know about nerve cell conduction of charges along the neurones but does something similar happen in the cell wall of simpler life forms?

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  15. D-9 Registered Member

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    As others have said, water is a very good solvent, because of its polarity. Also the way that water molecules are attracted to itself and other objects make it ideal for certain tasks like being sucked up by plant roots and being dispersed throughout the plant.

    Water has a high specific heat rating, which means it takes a lot of energy to change the temperature of water. So it acts like a thermal regulator, large bodies of water (lakes, or near the ocean) make the surrounding land less extreme in their temperatures year round, this property also makes it ideal for use in sweating or evaporative cooling.

    One thing that a lot of people overlook, which really is important for life on Earth, is that water is less dense as a solid than a liquid. Because of this, when a lake or Ocean gets cold, you get a layer of ice on top of the water acting as an insulator for the lower layers keeping it in a liquid state. Without this rather unique property lakes and oceans would freeze solid killing most to all of the life in the water.

    So while it is an incredible molecule in its own right, our planet is predominantly water on the surface, so life here has an incredible bias towards it, evolving in a watery environment for billions of years as that is what Earth has to offer. Water does have its limits; where temperatures would be too cold, other medians like liquid methane could be vastly abundant and support life as theorized on Saturn's moon Titan.
     
  16. Captain Kremmen All aboard, me Hearties! Valued Senior Member

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    Yes the Polarity means that it can dissolve both Organic and Inorganic chemicals.
     
  17. arauca Banned Banned

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    Inside in the cell there are some organelle and they have membranes , acriss the membrane you develop charges based on ionic ions and ions will control Ph, and proteines mobility depend on ionic charges of the media.
     
  18. Robittybob1 Banned Banned

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    You are right. It has been a long time since I've looked inside a cell. So much to learn discuss remember argue. On it goes!

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  19. Fraggle Rocker Staff Member

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    There's no good reason to assume that it can't. Life on earth evolved metabolic and other processes that use saltwater as a medium because the earth is covered with saltwater. Life that evolves on another planet will develop processes that use the most common environment on their planet as a medium,
     
  20. Nasor Valued Senior Member

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    The pH of water is only "neutral" because we define a pH of 7 to be neutral. We only chose 7 because that's the pH of water.
     
  21. kwhilborn Banned Banned

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    Easy answer would be: probably to move. If we were just the other chemicals in our composition we would be a giant Mostly Carbon solid.

    When I say we; I mean all life including cells.
     
  22. arauca Banned Banned

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    Yes we should solid state and have all over the body solar cells , we would not need water we will feed out brain with solar energy Our brain will be a hard drive and the creator will be the programmer of the soft ware, Note : there will be no free will.
     
  23. Robittybob1 Banned Banned

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    He could program that in too.

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