What is life?

[9-10ths_Penguin]

I said life, not metabolism. Its a word...look it up.

You asked about the quality that distinguishes a living being from a dead body; that's metabolism. A living being has a functioning metabolism and a dead body doesn't.

I'm sorry if you're looking for something deeper, but that's the answer to your question.

 

[Sonofason]

You asked about the quality that distinguishes a living being from a dead body; that's metabolism. A living being has a functioning metabolism and a dead body doesn't.

I'm sorry if you're looking for something deeper, but that's the answer to your question.

No, I actually didn't ask about the quality that distinguishes a living being from a dead body. I asked what is life, and I defined life as it is defined in the dictionary as the quality that distinguishes a vital and functional being from a dead body or inanimate object. Sorry you misunderstood. Better luck next time.

 

[Twilight Hue]

Is dna life?

 

[HonestJoe]

I'm just saying, this life we all have is the same life. It is ancient. There is no new life. All life on this planet is very old life, that has been perpetuated through various living bodies throughout all of history. No person alive knows of a new instance of life. All life comes from previous life, and so far, it has not ceased.

I think the problem is that you are taking the definition of life as a concept or ethereal quality (correctly IMO) but going on to treat it as if it is some kind of physical object or energy, a thing that actually exists.

Life in this context is like “height” or “colour”. Lots of things have these properties, lots of things can gain or lose them a lots of things with them are created and destroyed. It wouldn’t make any sense to say “There’s only one ‘height’ that we all share” though.

 

[9-10ths_Penguin]

No, I actually didn't ask about the quality that distinguishes a living being from a dead body. I asked what is life, and I defined life as it is defined in the dictionary as the quality that distinguishes a vital and functional being from a dead body or inanimate object.

These two statements are different how, exactly?

 

[beenherebeforeagain]

Keep in mind the definition we are using. It doesn't seem plausible to me that life should grow. Our bodies grow, but the life or intrinsic quality that separates us from corpses and inanimate objects does not grow. With that in mind, I seriously doubt that life has a need to eat, to kill or to survive. But you're right, life seems to depart us if we do not give our bodies the nourishment our bodies need to support the life that is in us.

Why does it not seem plausible that life should grow? The evidence of it growing is all around us. It grows, it evolves, it changes, adapting to its environment as it changes its environment. How exactly have you measured the "quality" that you describe as life to show it does not grow? And that you have exactly the same "life" as your parents?

As 9/10s said, the word "metabolism" seems to succinctly and accurately describe what makes the living different from the nonliving and the dead. Metabolism is an emergent property of carbon chemistry in the context of living organisms here on earth, meaning it does not have a separate existence from the materials and energy of the system, and only exists within a certain range of parameters of the material environment. Life ceases if you lower the temperature to the point that the chemical processes slow to stopping, or if you raise the temperature to the point that the chemical bonds begin to break down.

 

[Sonofason]

Is dna life?

DNA is not life.

 

[Twilight Hue]

DNA is not life.

Yep. Don't totally disagreee. In light that it replicates makes it very interesting to see how life gets defined from what is considered not alive and living.

 

[Sonofason]

I think the problem is that you are taking the definition of life as a concept or ethereal quality (correctly IMO) but going on to treat it as if it is some kind of physical object or energy, a thing that actually exists.

Life in this context is like “height” or “colour”. Lots of things have these properties, lots of things can gain or lose them a lots of things with them are created and destroyed. It wouldn’t make any sense to say “There’s only one ‘height’ that we all share” though.

You may very well be right about that. I do wish I were a bit more educated in the fields of anatomy and physiology...that might help.

So, here we are, living, breathing organisms. According to Rose Eveleth (SMITHSONIAN.COM), each of our bodies is composed of approximately 37.2 trillion living cells, which amazingly all contain a blueprint (the DNA) for the design of every other cell and system in our bodies. But that's beside the point. So the question arises...and surely its been asked..."Can we really consider a human being to be alive, or is it just the cells of the human body that are alive?"

Now that I have gotten a few responses to this thread, I was beginning to think that maybe my definition was somewhat lacking. Maybe I should do some research. I had defined life as "the quality that distinguishes a vital and functional being from a dead body or inanimate object". So I started looking for an alternate definition. Anyway, I found this definition:

"Life is self-reproduction with variations."
(http://www.ncbi.nlm.nih.gov/pubmed/21875147)

Clearly, living cells are capable of reproducing, and so are human beings capable of reproducing. The aspect of variation in this definition, I will mostly leave alone because anything related to Darwinian evolution seems to be untouchable ground, and there surely is a great deal of variation between life forms. The problem with introducing variation into the definition of life is the fact that all living organisms, whether single celled organism or multi-celled organisms have the exact same quality that distinguishes their vital and functional being from a dead body or inanimate object". So what about the first part..."life is self-reproduction"? While it is true that for all practical purposes all living cells and all living organisms are capable of reproduction, not all living organisms actually reproduce. Life cannot be "self-reproduction", otherwise we could not say that we are truly alive until we have reproduced. While the cells in my body are busy reproducing and therefore by this definition alive, although I have that quality that distinguishes a vital and functional being from a dead body or inanimate object", I may not have reproduced. This would mean that I am not alive, but the cells of my body are alive. Or the definition has a flaw. If I am indeed alive, and if reproduction must be a part of the definition for life, it would have to be that there is some quality or thing that distinguishes a vital and functional being from a dead body or inanimate object that is capable of reproduction likely with variation.

Now 9-10ths_Penguin seems to believe that I'm talking about metabolism, perhaps meaning that metabolism is indeed the quality, the something that all living beings have that distinguishes them from non-living beings and inanimate objects. Maybe he's right. It certainly seems correct to say that where metabolism is taking place, life is present. But does that mean that life is metabolism? Or is there something else present which causes or allows metabolism to take place? I don't know, and of course that is the reason I started this thread.

So then, it could be that I am mistakenly attributing to the concept of life some attribute of physicality that doesn't really exist, 9-10ths_Penguin could be right and life is simply metabolism, or there is some physical and tangible quality that living beings have that inanimate objects do not have which allows metabolism, reproduction and variation.

The goat herder said, "And the LORD God formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became a living soul." (Genesis 2:7)

 

[Sonofason]

Yep. Don't totally disagreee. It replicates though.

It depends on how we define life, and I'm not sure that's 100% decided. Some people believe that a virus is alive. But viruses do not metabolize nor do they have cell structures. But they do contain DNA or RNA, and do replicate. There's always a wrench thrown into the mix, making it impossible to be sure of anything.

 

[Sonofason]

These two statements are different how, exactly?

Actually I owe you an apology. You're answer was a great answer...I just didn't recognize it, and actually took it as though you were being facetious. I see know that I was mistaken, and you gave a very good answer.

However, I do not completely agree with you.

I see now that what you were saying is that metabolism is the quality, the something that all living beings have that distinguishes them from non-living beings and inanimate objects. I believe you're right about that. It certainly seems correct to say that where metabolism is taking place, life is present. But does that mean that life is metabolism? Or is there something else present which causes or allows metabolism to take place? I don't know, and of course that is the reason I started this thread.

So then, it could be that I am mistakenly attributing to the concept of life some attribute of physicality that doesn't really exist, you could be right and life is metabolism, or there is some physical and tangible quality that living beings have that inanimate objects do not have which allows metabolism to take place. So what do you believe causes metabolism to take place?

 

[beenherebeforeagain]

When I was a young lad and learning about biology, there was a list of traits that, taken together, generally described life. Minimal life, such as viruses, might display some of the traits, but not all. These included metabolism, respiration, ingestion, excretion, reproduction, reaction to stimuli, growth...it seems like there were seven, and I'm too tired tonight to go look up the list, if it's still even used, and if I've got them right. There are also ideas about a certain level of minimal complexity, boundedness (cells, for example), composition, energy flow, inheritance of traits, and so on.

Regardless, it appears that "life" is an emergent property of the systems we consider to be living. There might be some "living breath" that imparts "life" to these otherwise inanimate substances, but so far as I know, careful accounting of energy and material inputs and outputs really leaves little to no room for some other "separate" force in the system.

 

[Sonofason]

Why does it not seem plausible that life should grow? The evidence of it growing is all around us. It grows, it evolves, it changes, adapting to its environment as it changes its environment. How exactly have you measured the "quality" that you describe as life to show it does not grow? And that you have exactly the same "life" as your parents?

As 9/10s said, the word "metabolism" seems to succinctly and accurately describe what makes the living different from the nonliving and the dead. Metabolism is an emergent property of carbon chemistry in the context of living organisms here on earth, meaning it does not have a separate existence from the materials and energy of the system, and only exists within a certain range of parameters of the material environment. Life ceases if you lower the temperature to the point that the chemical processes slow to stopping, or if you raise the temperature to the point that the chemical bonds begin to break down.

First I want to mention that there are so many definitions for the word life, this becomes confusing. And I want to be sure we're still using the same definition, and not introducing new meanings in our discussion. I do not intend to say that I have the same life (life experience) as my parents. If 9/10 is right in saying that metabolism is the quality that distinguishes life from all other dead or inanimate objects, I am certainly not trying to suggest that I have the same exact metabolism as my parents. I say I have the same life as my parents because nothing died with the transfer of life from my parents to me. The life that was in each of my two parents, which I am also claiming was the exact same life, came together and now I am alive too. I call it my life now because the life given to me by my parents now exists in my own body. My father's sperm fertilized my mother's egg, and I am the result. However my father's sperm never died. My mother's egg never died. At some point in my life, hopefully I will be an old man. Once I was a child. Before that I was a baby, and before that I was a fetus. Before that I was a zygote (an a diploid cell resulting from the fusion of two haploid gametes; a fertilized ovum.) Before that I was my father's sperm and my mother's egg. The life in me existed long before I was born. I contend that the life in me existed long before anyone was born. But that I can't prove...not yet.

I agree that I did not give 9/10 his due credit. For some reason, I must have been feeling a little defensive and did not treat his response to me appropriately. I actually thought he was being facetious. I see that I was wrong, and that he actually gave an excellent answer to my question, albeit I do not agree with him. I believe that there is something in a living being (life) that allows metabolism to take place, It may very well be that metabolism is the quality that distinguishes a living body from dead bodies and inanimate objects, but that only leaves me with the impression that the definition I gave for life is not a completely satisfactory definition for life.

Now you say that metabolism is "an emergent property of carbon chemistry". Can you explain for me what you mean by that? For example, when I look up a definition for metabolism, I get this: the chemical processes that occur within a living organism in order to maintain life. Honestly, that tells me nothing at all. What causes metabolism to take place. What is special about organic living compounds that enable them to metabolize food/water/energy?

 

[Twilight Hue]

That's the thing about viruses. They demonstrate both qualities attributed to what is not regarded as living matter to what is.

I think the best possible key as to what is best defined as life lies primarily with viruses at present.

 

[Sunstone]

Nick Lane, The Vital Question.

 

[beenherebeforeagain]

First I want to mention that there are so many definitions for the word life, this becomes confusing. And I want to be sure we're still using the same definition, and not introducing new meanings in our discussion. I do not intend to say that I have the same life (life experience) as my parents. If 9/10 is right in saying that metabolism is the quality that distinguishes life from all other dead or inanimate objects, I am certainly not trying to suggest that I have the same exact metabolism as my parents. I say I have the same life as my parents because nothing died with the transfer of life from my parents to me. The life that was in each of my two parents, which I am also claiming was the exact same life, came together and now I am alive too. I call it my life now because the life given to me by my parents now exists in my own body. My father's sperm fertilized my mother's egg, and I am the result. However my father's sperm never died. My mother's egg never died. At some point in my life, hopefully I will be an old man. Once I was a child. Before that I was a baby, and before that I was a fetus. Before that I was a zygote (an a diploid cell resulting from the fusion of two haploid gametes; a fertilized ovum.) Before that I was my father's sperm and my mother's egg. The life in me existed long before I was born. I contend that the life in me existed long before anyone was born. But that I can't prove...not yet.

I agree that I did not give 9/10 his due credit. For some reason, I must have been feeling a little defensive and did not treat his response to me appropriately. I actually thought he was being facetious. I see that I was wrong, and that he actually gave an excellent answer to my question, albeit I do not agree with him. I believe that there is something in a living being (life) that allows metabolism to take place, It may very well be that metabolism is the quality that distinguishes a living body from dead bodies and inanimate objects, but that only leaves me with the impression that the definition I gave for life is not a completely satisfactory definition for life.

Now you say that metabolism is "an emergent property of carbon chemistry". Can you explain for me what you mean by that? For example, when I look up a definition for metabolism, I get this: the chemical processes that occur within a living organism in order to maintain life. Honestly, that tells me nothing at all. What causes metabolism to take place. What is special about organic living compounds that enable them to metabolize food/water/energy?

"An emergent property is a property which a collection or complex system has, but which the individual members do not have. A failure to realize that a property is emergent, or supervenient, leads to the fallacy of division."-- from researchgate

Metabolism is a property that living cells have that the constituent parts (the organelles, chemical compounds within, etc) do not have without the entire system being present. DNA is not alive, but it certainly appears that in life on earth, DNA must be present as part of the system for the system to be alive.

That there is an uninterrupted trail of living ancestors all the way back to the first life is undoubtedly true--in that those ancestors were alive, having come from previous living ancestors, and having reproduced living descendants. The origins of that first life is still not known (the problem of biogenesis), but various studies have demonstrated the ease with which many of the basic compounds of carbon chemistry can form in the presences of water and energy.

 

[Sonofason]

"An emergent property is a property which a collection or complex system has, but which the individual members do not have. A failure to realize that a property is emergent, or supervenient, leads to the fallacy of division."-- from researchgate

Metabolism is a property that living cells have that the constituent parts (the organelles, chemical compounds within, etc) do not have without the entire system being present. DNA is not alive, but it certainly appears that in life on earth, DNA must be present as part of the system for the system to be alive.

That there is an uninterrupted trail of living ancestors all the way back to the first life is undoubtedly true--in that those ancestors were alive, having come from previous living ancestors, and having reproduced living descendants. The origins of that first life is still not known (the problem of biogenesis), but various studies have demonstrated the ease with which many of the basic compounds of carbon chemistry can form in the presences of water and energy.

okay, thanks for the explanation. I understand.

 

[Marsh]

It seems to me that the life in me has existed long before it embodied me.

Why would you think that? Can you recall a life before your life?

This word, "life" that I am referring to here is best described as the quality that distinguishes a vital and functional being from a dead body or inanimate object...

Read Issac Asimov's book, Life and Energy (1962), it will leave you questioning everything you thought you understood about biological life.

If life is something that exists, how many exist?

What? You want to know how many viruses and bacteria exist in the world? That's what it sounds like you are asking. Life is not a "thing" it is a state of being for certain bio-chemical entities that we call life forms. I would say anything that has a means of replicating itself should probably be call "alive."

 

[Marsh]

"And the LORD God formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became a living soul."

Were bacteria given temporary nostrils? This passage strikes me as a poetic description of how the author imagined (in his bronze age world), in the absence of any scientific understanding, how his god gave life to a man fashioned from clay.

 

[Ran]

Hey, maybe u want to see this video
The meaning of life: