Life

[Clipper]

Does every living thing require water to live, or some trace of liquid?

[CharonY]

All known biochemical process relevant to organisms require an aqueous environment. As such, yes, biological activities require water. However, certain organisms can survive in a dessicated state. They do need water to resume activity, though.

[Mr Skeptic]

Yes all known life requires water, and this is necessarily so from our chemistry (see condensation and hydrolysis reactions). I'd consider intelligent robots life, and they would not require water.

[Ophiolite]

I'd consider intelligent robots life, and they would not require water.

You would want to wash them down occassionally, when they got grubby.

[jess]

Stars don't need water or any liquid substance or fire I think worms might be able to as well but I'm not sure.

 

Well I'm not sure if most people consider fire as living but stars are alive.

[Leader Bee]

Stars don't need water or any liquid substance or fire I think worms might be able to as well but I'm not sure.

 

Well I'm not sure if most people consider fire as living but stars are alive.

 

How'd you figure that? They don't reproduce, breathe or grow.

[jess]

Because they can die and nothing that is in space would be able to breath like we do.

[ajb]

Because they can die and nothing that is in space would be able to breath like we do.

 

So the nuclear fusion processes occurring in the core of a star can cease when the nuclear fuel is spent. But this is not what any biologist would mean by "die" as this must presuppose that the star was "alive".

[Leader Bee]

Similar to how a car would die once your fuel tank is empty. Doesn't mean it was necessarily alive to begin with.

 

A cars engine also needs to "breathe" for combustion to occur but there are more requirements that what I stated previously to be considered alive.

[jess]

No one really knows weather they are alive or not the only evidence that scientists can gather are dead or chips off a star but I believe that they are alive and also there made out of particles of hydrogen so yes it dose need water

---

Merged post follows:

Consecutive posts merged

Similar to how a car would die once your fuel tank is empty. Doesn't mean it was necessarily alive to begin with.

 

A cars engine also needs to "breathe" for combustion to occur but there are more requirements that what I stated previously to be considered alive.

 

But you can not refuel a star and a car is man made

 

trees don't breed ether

Edited July 2, 2010 by jess
Consecutive posts merged.

[ajb]

No one really knows weather they are alive or not the only evidence that scientists can gather are dead or chips off a star...

 

I don't know what you are referring to here. People have made many observations of the Sun including the solar wind.

 

Do you mean meteorites? These are old relics from the creation of our solar system.

 

Can you be more specific about what you mean here?

 

 

but I believe that they are alive...

 

Try not to believe anything. What is the evidence telling you should be more of a priority.

 

...and also there made out of particles of hydrogen so yes it dose need water

 

Hydrogen and Helium are indeed major components of the Sun. There is not any water making up the Sun. It is too hot and dense for that. The solar wind is mostly electrons and protons, again no water.

[jess]

mate I'm 15 and a lot of stuff can not be explained We still don't know fully how the human body works

 

 

what I mean is no 1 is able to take a live star to there lab. they might be able to see what happens on the out side but not on the in.

[ajb]

what I mean is no 1 is able to take a live star to there lab. they might be able to see what happens on the out side but not on the in.

 

Well, we can make plasmas in the lab. I don't recall anyone saying these are alive.

 

 

Also you should look up heliosismology. One can study acoustic pressure wave to examine the Sun.

 

 

As far as I am aware, there is no consensus on the definition of "life". However, it would take a very wide definition of "alive" to include plasmas and stars as life forms. For sure as we learn more about biology, our notions of alive and organism are under review. I have yet to meet anyone who seriously thinks stars are alive.

[jess]

It's just my opinion I believe that stars are alive fire, spirets and extraterrestrial and not just to believe in what you can see

[ajb]

By the way, welcome to Science Forums.

[jess]

lol thanx mate

nice dp

[Mr Skeptic]

The way I figure it, stars are exactly as alive as live ammo or a live wire. Really it depends on what you mean by "alive", but by the biological definition they are not alive.

 

Trees do breed by the way, don't know where you got the idea that they don't because they all do. Where did you think more trees come from?

[Leader Bee]

Taken from a thread debating the definition of life (Search Transhumanism: Man vs Machine)

 

Given the following definitions then, it would be debateable whether or not an android is indeed alive or not, especially in regards to point 7.

 

Since there is no unequivocal definition of life, the current understanding is descriptive, where life is a characteristic of organisms that exhibit all or most of the following phenomena:

 

1) Homeostasis: Regulation of the internal environment to maintain a constant state; for example, electrolyte concentration or sweating to reduce temperature.

 

2)Organization: Being structurally composed of one or more cells, which are the basic units of life.

 

3)Metabolism: Transformation of energy by converting chemicals and energy into cellular components (anabolism) and decomposing organic matter (catabolism). Living things require energy to maintain internal organization (homeostasis) and to produce the other phenomena associated with life.

 

4) Growth: Maintenance of a higher rate of anabolism than catabolism. A growing organism increases in size in all of its parts, rather than simply accumulating matter.

 

5) Adaptation: The ability to change over a period of time in response to the environment. This ability is fundamental to the process of evolution and is determined by the organism's heredity as well as the composition of metabolized substances, and external factors present.

 

6) Response to stimuli: A response can take many forms, from the contraction of a unicellular organism to external chemicals, to complex reactions involving all the senses of multicellular organisms. A response is often expressed by motion, for example, the leaves of a plant turning toward the sun (phototropism) and by chemotaxis.

 

7) Reproduction: The ability to produce new individual organisms, either asexually from a single parent organism, or sexually from two parent organisms.

 

Choose a selection of the above that apply to the sun and explain your reasoning for the answers. I find it unlikley that these will apply to a star, though some might with a bit of imagination.

[ajb]

I find it unlikley that these will apply to a star, though some might with a bit of imagination.

 

1) I can see holds. Stars can be in a "steady state". The gravitational collapse is balanced by outward pressure.

 

6) Also holds, stars will certainly be influenced by strong enough electromagnetic or gravitational fields. But much in the same way, electromagnetically as any plasma would and gravitationally as any massive body would.

 

7) Sort of, when a star goes supernova it can later form another star. This process creates heavier matter that can then go on to form planets in the stars system.

 

The others to me would need some modification to fit the bill. Obvious lacking is the requirement to be made of cells.

 

Serious question. Can the requirement of cells be loosened? I am wondering if virus is included here. Are viruses consider to have cells? I know they require a host cell to reproduce, but this is not the same thing.

[Leader Bee]

1) I can see holds. Stars can be in a "steady state". The gravitational collapse is balanced by outward pressure.

 

6) Also holds, stars will certainly be influenced by strong enough electromagnetic or gravitational fields. But much in the same way, electromagnetically as any plasma would and gravitationally as any massive body would.

 

7) Sort of, when a star goes supernova it can later form another star. This process creates heavier matter that can then go on to form planets in the stars system.

 

The others to me would need some modification to fit the bill. Obvious lacking is the requirement to be made of cells.

 

Serious question. Can the requirement of cells be loosened? I am wondering if virus is included here. Are viruses consider to have cells? I know they require a host cell to reproduce, but this is not the same thing.

 

 

Number 6 doesn't really hold for stars; the requirement is a response to stimuli - If i push a rock it will move but it isn't really proactively responding to me touching it, though it is being influenced by me exerting a force on it.

 

Same with a star, it doesn't choose to move but follows the laws of physics which as you say it is influenced by, but certainly not responding to.

 

A virus I would assume does fit the requirements to some degree, but my knowledge of this area isn't really good enough to say so. The requirements say that to classify as life that most points must be met, not all.

 

These are only guidelines however as there is no 100% definition of life.

 

Would a sufficiently intelligent computer that could pass the turing test be classified as life?

[ajb]

A virus I would assume does fit the requirements to some degree, but my knowledge of this area isn't really good enough to say so. The requirements say that to classify as life that most points must be met, not all.

 

My naive understanding is that it will depend on who you ask if viruses, prions and similar are alive or not. I don't know enough to offer any real opinion.

 

These are only guidelines however as there is no 100% definition of life.

 

Indeed. I don't know if there ever will be a very concise all accepted definition.

 

Would a sufficiently intelligent computer that could pass the turing test be classified as life?

 

I know this is very much debated. It is though by some that the Turing test will not be enough. However, you have raised a good question. Again, not one I have an opinion on.

[pioneer]

All known biochemical process relevant to organisms require an aqueous environment. As such, yes, biological activities require water. However, certain organisms can survive in a dessicated state. They do need water to resume activity, though.

 

Without water, the organic framework of life can exist in a suspended state. However, to reactive all the properties associated with life, we need water. The DNA double helix also has a double helix of water. If we dehydrated the DNA, it no longer becomes viable for life. Add water back and we are back in business.

 

Conversely, life can not exist with water alone. Rather, water needs the organic framework of life based on C,N,O,H,P,S, etc.. Once the organic framework is set up, water can animate the scaffolding. This is evident in dehydrated organisms, where all the scaffolding of life comes alive during rehydration.

 

It is not coincidence that the molecules of life are dependent on the secondary bonding called hydrogen bonding. What is needed for the functionality of the DNA, RNA and proteins, is also the same used by water. This is how water interfaces to the organics to impart life.

 

Life evolved in water, with water the main component, right from the beginning. The evolving organics needed to conform to the potentials found in water or else they would increase the potential energy within the water (surface tension). Since water was the big guy, and nature likes to lower energy, organics lowered potential in the image of water; h-bonds.

 

The question becomes, what is there about water that allows it to uniquely add life to the organic scaffolding of life? In the liquid state, the molecule H2O will only exist for about 1 millisecond, before the H swap oxygen. One of the effects is what we call pH. The net result is hydrogen bonding is assisting the breaking of covalent bonds at ambient conditions. This easy change of state allows water to transmit information through the water.

 

This is combined with the observation that the H proton of water is the fastest thing in water, able to outrun Na+ by a thousand-fold.

 

The net result is water is able to react to moving solutes molecules and fixed surface signals and then transmit the information through the water via the adjustments in the H. The speedy H is way ahead of solutes. The destination water is reacting to the information, conforming, tugging on the local organic surfaces and solutes, making these ready. Then the slower boat organics and ions arrive, the organic scaffold is already primed. If we use other solvents, the information is garbled and the tug is not the same.

 

Water by transmitting information imparts life to the scaffold. We take away the water, there is a communication breakdown and life stops.

 

.

[Mr Skeptic]

Serious question. Can the requirement of cells be loosened? I am wondering if virus is included here. Are viruses consider to have cells? I know they require a host cell to reproduce, but this is not the same thing.

 

Viruses are not considered to be cells, and also not considered to be alive by most biologists. A few do consider them alive, and everyone agrees that they're borderline. Viruses don't really reproduce; they infect a cell and the cell produces viruses. This is similar to prions, which are even simpler.

[CharonY]

Virus are not cells but mostly protein plus nucleic acids, prions are just extremely small proteins. Unlike viruses prions do not replicate but change existing prions.

Nonetheless even they require water to function.

 

And indeed there are no strict definitions of life. Most are of the post hoc variety.

[jess]

ok ok you've proven me wrong lol