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Difference between living and non-living matter

SkepticalScience

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S
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Can someone tell me the scientific difference betwen living and non-living matter?

What exactly has changed during the transition between life and deat?

So - say I have a living cell and a dead cell. What is the difference exactly between the two??

Thanks,
SS
 
SkepticalScience said:
Can someone tell me the scientific difference betwen living and non-living matter?

What exactly has changed during the transition between life and deat?

So - say I have a living cell and a dead cell. What is the difference exactly between the two??

Thanks,
SS
Click to expand...

In my view not very much.

Life is just a word we use to describe certain characteristics of "stuff" we observe. In science it can be defined differently depending on exactly what is being described.

I always find it amusing that for some reason some people think the very utterance of the word “life” is somehow profound, it’s no more profound or intrinsically meaningful then saying some particular “stuff” is pink.
 
SkepticalScience said:
Can someone tell me the scientific difference betwen living and non-living matter?

What exactly has changed during the transition between life and deat?

So - say I have a living cell and a dead cell. What is the difference exactly between the two??
Click to expand...

This is a very difficult question, in part because things "live" at so many different scales. You're alive (or at least I presume so), but many of your body cells are not -- but conversely, if you were to "die" this minute, your cells would still be alive for some time (which is part of why organ transplants work). A biology teacher pointed out to me that there are probably still living cells in a piece of meat you buy at the butcher.

At the cellular level, it's largely a question of respiration. A live cell continues to do its happy little cell chemistry thing, including converting sugar and oxygen into ATP. A dead cell does not.
 
Re: Re: Difference between living and non-living matter

new drkitten said:
At the cellular level, it's largely a question of respiration. A live cell continues to do its happy little cell chemistry thing, including converting sugar and oxygen into ATP. A dead cell does not.
Click to expand...

Even within a cell, it does not magically have a live and dead state. Different organalies may continue working after necessary components of the cell have died. Heck, also look cells that are essentially dead and do nothing until they are activated (sometimes hundreds or thousands of years later).
 
Re: Re: Re: Difference between living and non-living matter

RussDill said:
Even within a cell, it does not magically have a live and dead state. Different organalies may continue working after necessary components of the cell have died. Heck, also look cells that are essentially dead and do nothing until they are activated (sometimes hundreds or thousands of years later).
Click to expand...

This is of course true, and I apologize if I implied otherwise.
 
Re: Re: Re: Re: Difference between living and non-living matter

new drkitten said:
This is of course true, and I apologize if I implied otherwise.
Click to expand...

relax, I was just expanding on your idea.
 
Originally posted by SkepticalScience


Can someone tell me the scientific difference betwen living and non-living matter?
Click to expand...
I think the short answer is:

No.
 
Just my two cents worth:

At the level of matter - there is no difference.
As you go up the scale in complexity and self organization, the line becomes less blurred. Most biologists I know don't consider something alive until it can perform self-organization and replication on its own, using organic raw materials. At least that is the paraphrased definition that I remember from many biology texts in my foggy past.

There are a few things on the edge such as viruses (can't replicate themselves without host cells), prions, and other assorted critters that I can't remember.
 
Process.

What's the difference between a car that's running and one that's not?

Process.

In living things we call it "life".

The difference between a living person and a dead one, is that one is alive and the other is not.

Why is that hard to grasp?

Yes, we can break the process down into electricity and chemistry and you can even throw in a "quantum" if you feel it helps. But it's the same in a person as in a car. Just about a billion times more complicated, due to a wacky process called "Evolution".
 
However, in the car you can restart and it runs, for most life that doesn't happen. (If we consider complex multicellurlar organisms.)

Of course then there the things like seeds and pupae, they don'r generaly show the traits of life but they can become alive.
 
SkepticalScience said:
Can someone tell me the scientific difference betwen living and non-living matter?
Click to expand...

Huh, AFAIK, living matter is what have some form of metabolism, experiences growth and death (ceases its metabolism) and have reproductive capabilites (either sexual or asexual).
 
Dancing David said:
However, in the car you can restart and it runs, for most life that doesn't happen. (If we consider complex multicellurlar organisms.)
Click to expand...
But the reason for that is probably just because a complex multicellular organism is so much more complex that a car. If you could go in and fix all of the broken parts in that organism, and put it back to a state where it could run, then you could in theory "restart it". However, whether this will ever be possible in practice...
Then again, isn't that sort of exactly what they do when they restart someone's heart? Just that the damage hasn't had time to become really complex and the system is still in a pretty functional state...
 
Dancing David said:
However, in the car you can restart and it runs, for most life that doesn't happen. (If we consider complex multicellurlar organisms.)
Click to expand...

Yet at some point the car will no longer restart, is it no longer a car at that point? Sorry for the philosophical sounding question but it is pertinent to this matter.

The analogy with a car is a good one.

A car can be defined in many different ways, so can life. For example a car is generally describe as something like “a self propelled vehicle”, yet that is only a handy quick definition since we will still call a “car” that is broken down (i.e. no longer self propelled) a “car”. Another example is the old banger in the garage at the start of a restoration project is still referred to as a car, yet a collection of component parts that will make a car when assembled (in a certain way) is not (generally) described as a car. This is again much like life in that we don’t describe the atoms and molecules that are the components of “life” as “life” until they are assembled (in a certain way).

I think when you get down to the brass tacks “What is a car?” is just as a profound and meaningful question to ask as “What is life?”. The answer is (for both) quite simple, it’s merely a way to describe a particular collection of components and processes so we can communicate with one another, neither holds any “intrinsic meaning” beyond that.
 
Argument by analogy is a perilous process in these parts.

Maybe comparing a single cell to a self repairing factory would be a closer model? Self repair can only cope with so much damage at a time.

More generally, what I'm getting at is that life is a dynamic process, not a material thing.

What's the difference between a lake and a river?
 
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