Good question! Yet, your question contains one statement: "there are organisms on Earth who do not need water to survive". Let me answer you with another question: Do you know of any organism on Earth who does not need water to survive? I challenge you to name one B)
Good question! Yet, your question contains one statement: "there are organisms on Earth who do not need water to survive". Let me answer you with another question: Do you know of any organism on Earth who does not need water to survive? I challenge you to name one B)
Sorry... my mistake. However, certain bacteria, such as the Atacama desert bacteria, can function for long periods of time without water. But why do living organisms need water? Why isn't some other substance able to be used for these necessary functions?
Sorry... my mistake. However, certain bacteria, such as the Atacama desert bacteria, can function for long periods of time without water. But why do living organisms need water? Why isn't some other substance able to be used for these necessary functions?
Indeed, those bacteria from the Atacama desert are really amazing organism. They challenge our understanding regarding the minimum supply of water required for life to exist.
For instance, it was estimated that the dry matter content of certain bacteria strain from the Atacama desert nearly doubles the average in bacteria living in less arid conditions:
This means they contain less water, but they do still contain quite a lot of water.
I am not sure whether or not the scientists carrying out research in that field know exactly how those bacteria manage to obtain and retain water in such an arid environment. But they do!
They are so resistant to harsh conditions that NASA scientists are even envisaging sending them to Mars:
So, in fact, all the living organisms we know so far need water. Water covers two thirds of Earth's surface and about two thirds of the human body is water (this changes with age: from 90 % in fetuses to 50 in elder people, our water content is decreasing as we get older!).
Being so abundant on the surface of the planet, it is not surprising that life on Earth had evolved making use of this molecule. Therefore, for us, it is very difficult to conceive that any form of life can exist in another planet which does not need water. This does not mean it does not exist, in fact, we have no clue. It is just hard to imagine for us.
But abundance is not the only reason why water is so important. Water presents, due to its chemical structure, very particular physical and chemical properties which made it suitable for sustaining life, for instance:
Indeed, those bacteria from the Atacama desert are really amazing organism. They challenge our understanding regarding the minimum supply of water required for life to exist.
For instance, it was estimated that the dry matter content of certain bacteria strain from the Atacama desert nearly doubles the average in bacteria living in less arid conditions:
This means they contain less water, but they do still contain quite a lot of water.
I am not sure whether or not the scientists carrying out research in that field know exactly how those bacteria manage to obtain and retain water in such an arid environment. But they do!
They are so resistant to harsh conditions that NASA scientists are even envisaging sending them to Mars:
So, in fact, all the living organisms we know so far need water. Water covers two thirds of Earth's surface and about two thirds of the human body is water (this changes with age: from 90 % in fetuses to 50 in elder people, our water content is decreasing as we get older!).
Being so abundant on the surface of the planet, it is not surprising that life on Earth had evolved making use of this molecule. Therefore, for us, it is very difficult to conceive that any form of life can exist in another planet which does not need water. This does not mean it does not exist, in fact, we have no clue. It is just hard to imagine for us.
But abundance is not the only reason why water is so important. Water presents, due to its chemical structure, very particular physical and chemical properties which made it suitable for sustaining life, for instance:
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Good question! Yet, your question contains one statement: "there are organisms on Earth who do not need water to survive". Let me answer you with another question: Do you know of any organism on Earth who does not need water to survive? I challenge you to name one B)
Sorry... my mistake. However, certain bacteria, such as the Atacama desert bacteria, can function for long periods of time without water. But why do living organisms need water? Why isn't some other substance able to be used for these necessary functions?
Indeed, those bacteria from the Atacama desert are really amazing organism. They challenge our understanding regarding the minimum supply of water required for life to exist.
For instance, it was estimated that the dry matter content of certain bacteria strain from the Atacama desert nearly doubles the average in bacteria living in less arid conditions:
http://tinyurl.com/cg99x9
This means they contain less water, but they do still contain quite a lot of water.
I am not sure whether or not the scientists carrying out research in that field know exactly how those bacteria manage to obtain and retain water in such an arid environment. But they do!
They are so resistant to harsh conditions that NASA scientists are even envisaging sending them to Mars:
http://science.nasa.gov/headlines/y2001/ast26jan_1.htm
So, in fact, all the living organisms we know so far need water. Water covers two thirds of Earth's surface and about two thirds of the human body is water (this changes with age: from 90 % in fetuses to 50 in elder people, our water content is decreasing as we get older!).
Being so abundant on the surface of the planet, it is not surprising that life on Earth had evolved making use of this molecule. Therefore, for us, it is very difficult to conceive that any form of life can exist in another planet which does not need water. This does not mean it does not exist, in fact, we have no clue. It is just hard to imagine for us.
At least in this planet H2O = Life :
http://www.amnh.org/exhibitions/water/
But abundance is not the only reason why water is so important. Water presents, due to its chemical structure, very particular physical and chemical properties which made it suitable for sustaining life, for instance:
http://www.hometrainingtools.com/articles/properties-water-science-teach...
Do you know of any other substance having all these properties?
Water is really special.