simplest life form???

[VendingMenace]

well, i think the title is somewhat explanitory -- what do you think is the simplest life form possible? Put another way what are the minimal requirements that must be met in order for something to be alive?

 

Some of the best discussions i have had concerned this question and while i have never really reached an adequate answer, i enjoy hearing others thoughts on this. So, i geuss i will start this off with what i am currently thinking...

 

I think any set of components that are able to self-replicate without the use of outside machinery (or mechanisms) is considered alive.

 

Under this defninition a virus would be considered not alive while a virus-host pair would be consdiered alive. Of course the host it self would be considered alive by itself. The problem with this definition of course is that a robot that could replicate itself, along iwth a source of power, would be considered alive. But then again, perhaps such a robot should be considered alive (but i personally don't think so). So something must be missiing from the definition. But what? I dont know :/

 

Anyways, i look forward to all your thoughts and insights into this question. Good day!

[iglak]

my definition, basically, is that it contains some sort of programming that defines it and determines basically everything(DNA, RNA, Binary computer code, some alien thingy...).

 

of course, that would mean viruses are alive, but i think they are.

 

oh, and in the future, when we can create robots that can reproduce and can do whatever. the way it reproduces is how it was told to through some binary code (or quatrinary like RNA), so that counts in my mind.

[Pinch Paxton]

Sometimes you have to ask the question.. "Are We Alive!" Some people think that when you die, you are truly born.

[Muffin]

I guess for something to live, it has to be born, grow, and die. For it to stay alive, it would need some kind of energy. Or maybe even a decent definition (for those of you who believe in evolution) would be something that evolves. Or maybe it could be something that reproduces, but I wouldn't really say that, cuz some ppl can't reproduce, but they're alive. (Yes, I know you may be looking at is an a species, but how could it be the definition, if the individual doesn't fit into it.)

 

I think I'll think about this some more, and get back to you. Interesting topic VM. (lol, do ppl call u that? I'm new and it seems like they would.)

[rune420]

To me it seems that the minimal criteria for something to be considere alive is for it to have a consciousness of some sort.

But I guess it depends on how you define the word 'life'.

[Muffin]

rune, that was my first thought, but then I thought....duh, plants.

[DeoxyriboNucleicAcid]

Well, in terms of whats "alive" nothing is really, we are all just a bunch of chemicals and elements put together in a bag of blood and bones. It may be disturbing to think like that, but thats the way it is.

 

Anyway, the simplest form of life I can think of is some form of monocellular life, such as bacteria, viruses, and other really tiny little thins. Good luck.

[VendingMenace]

yeah, plants do kinda through a kink into things... but then again, how would you define consciousness? Perhaps plants are conscience but we do not have an adequate definition to include them. I don't know.

 

Yes, I know you may be looking at is an a species, but how could it be the definition, if the individual doesn't fit into it

 

Ah, i was thinking about species. But you do raise an excellent point. Thanks! I suppose that the individual would have to fit the definition. Good call.

 

Ok, so then perhaps reproduction is right out as a requirement. Or perhaps people that cannot reproduce should be consdered as dead (becuase they are from an evolutionary standpoint). But i think this opens up a whole ethical can of worms, so to avoid that i will just say reproduction is right out.

 

hmmm...how about this; something is alive if it can actively change its immediate environment in order to directly benifit it? By "benifit" i mean insure its continued presense. What do you think of that?

 

 

cool, just few little things...

VM. (lol, do ppl call u that? I'm new and it seems like they would.)

 

Well, most people here don't seem to, for whatever reason. But the vast majortiy of peope online do call me VM, so you are more than welcome to, will save you some typing i think.

 

 

Sweet. One last thing, gotta tell you this joke muffin just because of your name. SO here it goes....

 

Two muffins are sitting next to eachother in an oven. On muffin turns to the other and says, "A bit hot in here, don't you think?" The other muffin then says, frightened, "AAHHHH! TALKING MUFFIN!!!"

 

Anyways, i love that joke. Cool.

[Pinch Paxton]

I was just doing a bit of chaotic thinking because I like turning things upside down. Do you suppose that a mouse feels that another mouse is more alive than a human?

[VendingMenace]

good question! I have no idea. Are there non-human animals that you feel (or have ever felt) are more alive than YOU?

 

I am not sure if i have. I think that our instinct for survival causes us to think of other things as "less alive." HOwever, this is counterbalenced by a mental desire to do "right" whatever that is. And this is what foces us to ask "what isalive?"

 

hmmm...just from an evolutionary standoint, i think i mouse would view other creatures as less important, if not actually less "alive."

 

Just my thoughts.

[Muffin]

hmmm...how about this; something is alive if it can actively change its immediate environment in order to directly benifit it? By "benifit" i mean insure its continued presense. What do you think of that?

 

That seems to be a good defenition. Only thing I can think of (a bit of a stretch) would be someone in a coma. Now, perhaps they can do some very minor things to make themselves more comforitable. Something that would go along with that, but is a bit different is all living things adapt.

 

I am very tempted to say "all living things can die", but then we'd have to define death. Maybe another one would be that they have genes (not sure about bacteria and stuff though). Like, they have to have some traits passed down from whatever they spawned from.

 

I don't know....i'll sleep on it and see what I come up with.

 

BTW, that muffin joke is priceless!

[VendingMenace]

Only thing I can think of (a bit of a stretch) would be someone in a coma.

 

nah, i don't think that is too much of a stretch. I think that is a very good point. A person in a comma cannot really effect his environment. As such, he would die. But he doesn't, because others are taking care of him. Thus, he is still alive (or at least i feel most people would call him alive). Because of this, my definition does not quite work. Good call.

 

well, i must admit that i am kinda stumped right now. Perhaps i need to sleep on this too.

 

well anyways, thanks for the feedback, glad you like the joke

[iglak]

reproduction

what about mutations that can't reproduce?

 

create energy

what if a cell coudn't produce ATP because of a mutation, and you fed it ATP?

 

dispose of waste

what if a mutation made it incapable of disposing of waste, and you had to do that too?

 

movement

this is about the only one that works

cells have to move (even if it's just a tiny bit) to stay alive and retain the ability to move.

movement allows it to act on it's environment (including the inside of the cell)

if it's not moving at all, it's just a pile of useless chemicals

 

so, i am changing my definition to: life = movement + structure

[Sayonara]

"What would Jean-Luc say?"

[VendingMenace]

what if a cell coudn't produce ATP because of a mutation, and you fed it ATP?

 

What if it could still convert the ATP to energy? It is not the ATP itself that is energy. The energy is a result that when you hydrolize ATP to ADP and Phosphorus, you can obtain energy. This energy when properly coupled allows the cell to make other chemicals and move. So even your definition of life=movemenet + structure would require that the cell is able to create energy (and harness it). SO, i think the ablilty to use energy is still and implicit requirement.

 

so, i am changing my definition to: life = movement + structure

 

Cool. That is some good thinking. I hope you don't mind if i point out some potential flaws?

 

First off, everything moves. People move, cells move, molecules move, atoms move, electrons move. EVERYTHING moves. It has to. Thus, movement is too broad of a definition in my mind.

 

Also, if you look close enough everything has structure as well. Again, peopple have structure, as do cells, molecules, atoms, and perhaps electrons (though maybe not in the case of an electron, depends on what you mean by "structure"). So i think this too is too broad of a definition.

 

Of course this is only too broad of a defnition if you don't want to consider molecules or rocks alive. Because both molecules and rocks have structure and do move, they would both be alive. Thus, i fear that your definition is not specific enough.

 

It is some good thinking though and perhaps i am missing the point you are trying to make. Of course i too have yet to come up with a good definition. I suppose all we can do is keep trying

 

 

How about something is alive it has the "ability to make use of resources at hand to benifite itself"

 

Where it is the same definition of benifit as above but "resources at hand" means resources in the environment or resources taht are being actively supplied. This would allow the coma patient to be alive still where the hospital would be supplying the "resources at hand". What do you think of that?

[Muffin]

That seems good. I was thinking a bit along the lines of like, what if there was no way to benifit it, and everything only harmed it. I can't think of a specific example, but maybe that could exist, I don't know. Maybe you could just change it to "ability to make use of resources at hand". Perhaps it is "something with different parts that all work together to survive." Even the tiniest living cells have that. To my knowledge at least.

[wolfson]

As for Atp oxadative phosphoryaltion has the largest output with 32 molecules of ATP... you couldnt feed it, you would use another form or by controlled drugs i.e. glycolisis or Krebs cycle ... kerbs cycle being best idea.. although you cant beat Oxadative phosphorylation.

[iglak]

VendingMenace said in post #15 :

SO, i think the ablilty to use energy is still and implicit requirement.

 

First off, everything moves. People move, cells move, molecules move, atoms move, electrons move. EVERYTHING moves. It has to. Thus, movement is too broad of a definition in my mind.

 

Also, if you look close enough everything has structure as well. Again, peopple have structure, as do cells, molecules, atoms, and perhaps electrons (though maybe not in the case of an electron, depends on what you mean by "structure"). So i think this too is too broad of a definition.

 

How about something is alive it has the "ability to make use of resources at hand to benifite itself"

i agree that the ability to use energy is an implicit requirement, but the ability to canvert energy into something usable is not

 

hmm... good point

although, that is not quite what i was trying to say, but i can't seem to find the right words to say it...

 

... also a good point

 

THAT'S IT!

"ability to make use of resources at hand to move".

"move" instead of "benefit itself" because of what muffin said.

ATP could be considered a rescource if it was being fed (and, yes, it is possible to feed ATP in at a rate equal to normal cellular respiration).

movement doesn't mean just externally. it could all be internal (dividing, protein synthesis, ATP synthesis, and so on).

 

now,

Life = "a structure with the ability to use rescources to move"

 

 

P.S. "a structure" means basically anything...

P.P.S. but wait, now that includes simple electric motors...

i suppose it has to contain some form of RNA, like i said first.... That works.

[wolfson]

Iglak i don't think you quite understand, i mean you can not feed ATP with the organism being able to transfer energy from chemical bonds to endergonic (energy absorbing) reactions within the cell, if the cell could not transport using a carrier protein or carrier bond then the alternative would be using the krebs cycle or glycolosis which produces 2 molecules of adenosine triphosphate (ATP).

[YT2095]

well call it making a bold statement of the obvious, but FIRE seems to fit the bill quite adequately too

let`s have a look at the current prerequisites for life according to Biology 101:

 

Movement: Fire moves

respiration: it sure does that when it gives off toxic gasses

sensitivity: it`ll move with wind

Nourishment: it uses fuel

excretia: it leaves ashes

reproduction: it sure does that

growth: it does that too

 

so realisticly to all intents and purposes fire COULD be considered a form of life too

I don`t class it as one personaly, but it sure begs an update of what "LIFE" is

[fafalone]

As far as viruses...

 

There should not be a rigid definition but rather a comparison... a virus is much more similar to a living organism than it is to a inanimate object.

 

As for fire, it's assumed that gaseous heat energy, not being made of the basic components of life, cannot be life.

[Muffin]

Iglak, you seem to be really stuck on the whole movement thing, so I'll help u out. If you want to use that, I'd stick the word "willfully" in there, whether it be instinct or concious, and that should do the trick.

[iglak]

Muffin said in post #22 :

Iglak, you seem to be really stuck on the whole movement thing, so I'll help u out. If you want to use that, I'd stick the word "willfully" in there, whether it be instinct or concious, and that should do the trick.

that could work, but is it willful if it isn't even instinct?

is it willful when one cell creates a simple protein?

that is actually the movement i am talking about, and i doubt everyone agrees on what will means so....

[iglak]

wolfson said in post #19 :

Iglak i don't think you quite understand, i mean you can not feed ATP with the organism being able to transfer energy from chemical bonds to endergonic (energy absorbing) reactions within the cell, if the cell could not transport using a carrier protein or carrier bond then the alternative would be using the krebs cycle or glycolosis which produces 2 molecules of adenosine triphosphate (ATP).

i still don't understand

i understand the processes of cellular respiration (just studied it in AP Bio), but i don't understand what you are saying.

 

i suppose i don't understand between "feed ATP" and "if the cell"

 

i understand that i don't understand. i also understand that if a cell was not able to get oxygen for oxidative phosphorilation, it would still go through glycolysis (creating 2 ATP) and fermantation. i don't understand the whole of what you are saying though.

[wolfson]

? ATP ?

 

Let me try and explain, maybe I’m not being clear enough for you, you seem to have reasonable knowledge of ATP synthesis so I will continue in-depth for you.

 

The adenine portion of adenine triphosphate consists of one molecule of adenine and the five-carbon sugar, ribose. The triphosphate portion of ATP consists of three phosphate molecules.

 

The RIBOSE could be used to generate ATP. In theory, supplementing your diet with additional ribose should increase the rate at which ATP is generated.

 

In the process of transposition of ATP, using CRT (Chemical Reactant Transportation), it provides energy for every move you make and every chemical reaction that occurs in your body.

 

The ATP must be Transposed Before it becomes accessible as “free energy”, that’s why we use Ribose to generate ATP, feeding ATP would one be a waste, at rate of Ab<>cD, and secondly if the “organism” that people are talking about could not use CRT then Ribose would be the likely alternative.

 

Energy is released when one of those phosphates is broken off from ATP. The compound then becomes adenosine diphosphate (ADP), which consists of adenosine and two phosphate molecules. ADP becomes adenosine monophosphate (AMP) when another phosphate molecule is broken off.

 

So the process of CRT with ATP isn’t simply “Feeding” ATP and it straight away becomes energy, the process is much more complicated, and if a organism wasn’t able to use CRT then the process of energy creation would not be possible. So as an alternative Ribose would be used to create glycolysis (anaerobic glycolysis) by means of glucose to pyruvate. Or maybe even Krebs cycle, oxidative Phosphorylation with the aid of a amide. I hope you now understand were I was coming from!