How to define life?

[Kent]

My prefessor gave the class a working definition of what life is. He states that life is a self-reproducing chemical system. I think that definition might perhaps be too limited. What do you think?

[Jay-qu]

How about a mule? they dont reproduce :)

 

There are many things that have been considered when defining life, each with examples and counter examples. It is a very tough definition to pin down.

 

The point of reproduction alone would not define life. Some others I have heard of is: motabolise, evolve, react to stimuli etc.

[ronthepon]

There has been a good deal of discussion on this here. I strongly reccomend that you have a look before you carry on with your discussion on this thread.

 

The discussion can be found here

[InfiniteNow]

How about a mule? they dont reproduce

Ahhh, but the cells which compose that mule do. ;)

 

 

Per ron's request, however, please continue in the other thread. :)

 

 

Cheers. :cup:

[HydrogenBond]

Life is a phenomena, based on the hydrogen proton, where a range of stable hydrogen proton potential gradients are established to create a self perpetuating system. This is true for both single and multcellular life forms, with multicellular lifeforms having a larger secondary layer of hydrogen protons gradients that interact with the lower level cellular gradients Reproduction is a way for one living hydrogen proton gradient system to create another self perpetuating hydrogen proton gradient system of very similar characteristics.

[arkain101]

Life:

 

The only thing that appears capable to clarify a point of time in the universe.

[infamous]

How to define life?

 

The attribute which enables a molecular complex to manipulate it's enviornment to it's determined advantage....................Infy

[Tarantism]

"life" is any moment when a being is able to manipulate or be manipulated but its enviorment.

 

a "life time" is a series of these moments strung together by memory. as in: a moment of life plus time.

[mir]

Let me remind you about the latest discovery of the "giant viruses" (big as a bacteria). The discovery questions the definition of life all in all: See giantvirus org (cant post url's yet).

[InfiniteNow]

Life = That which is   :)

/forums/images/smilies/banana_sign.gif

[Southtown]

There's also nanobes, which are controversial.

 

http://en.wikipedia.org/wiki/Nanobe

[hallenrm]

Dear Kent,

 

If you really want to know the opinions of many hypographers ay one go, I would suggest that you read the article "What constitutes life" in the articles section of this forum. :)

[ronthepon]

Ahhh, but the cells which compose that mule do.

Yes, although there are cells that remain in interphase state for ever, yet are said to be alive.

 

Neurons live, but don't reproduce.

[InfiniteNow]

Yes, although there are cells that remain in interphase state for ever, yet are said to be alive.

 

Neurons live, but don't reproduce.

You are correct that nerve cells don't reproduce in the sense of cell division and cycles, however, old nerve cells do die and new nerve cells can grow. :)

 

An important note, one limitation to the proposal that nerve cells do not "reproduce" is that studies on reproduction of nerve cells have generally been limited to the neocortex, and the findings might not apply to all areas of the nervous system... Pending further data. ;)

[InfiniteNow]

To answer the thread's subject question, "What defines life?"

 

Death.

 

 

The truth is contained by it's opposite. :)

[Drip Curl Magic]

Considering everything I've learned from living.

 

I'd have to say

 

That life is everything.

 

Because, quite honestly, Life is all I remember.

[HydrogenBond]

If one looks at all these definitions of life one might conclude that the current understanding of life is still quite philosophical. This is why the sc life science are still very empirical.

 

If one defines life in terms of self perpetuating systems based on the hydrogen proton and hydrogen proton gradients one is able to get out of the realm of philosophy and start doing some rational science.

 

What makes cells living is that a hydrogen proton potential gradient is created between the cell membrane and the genetic material. The cell perpetuates this potential providing a constant source of energy potential. The cell also connects this gradient with the hierarchy of intercellular activity, part of which maintains the primary gradient.

 

When a cell enters the cell cycle, the primary gradient is altered. This change of potential, alters the organization of the innards that had connected the interphase gradient. The result is a new gradient organization which culminates in the DNA being dupicated and the cell dividing. The division once again alters the primary gradient causing the cell to reform the material gradient back to interphase.

 

When we talk about multicellular animals, like humans, there are many additional levels of hydrogen proton gradients. The primary one is between the nervous tissue and the blood supply. Connecting this gradient are all the organs, which are a combination of these two tissues. The organs have their own gradient hierarchy with the primary gradient of the human body between the brain and heart. The brain itself is set up as gradients between the cerebral matter and brain stem. Consciousness itself is set up as neutral organization that both connects and perpetuates these primary neural gradients. Life is very holographic using a basic hydrogen proton gradient template that gets increasingly complex as life evolves.

 

All the biochemistry of life is what is needed to connect and perpetuate the gradients. It also help perpetuate lower gradient layers allowing higher and higher layers of gradients a solid foundation so life can evolve. Based on this on should be able to predict the future of life,since it would merely be new intermediary layers of gradient potential or higher layers of gradient potential added on top of the heap.