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mercury
2004-Oct-17, 05:14 AM
Fellow member rahuldandekar has already started a topic called ‘Consciousness’. However for consciousness there should exist life. By A. J. Oparin’s suggestion, we all know that life first appeared in the sea. The amino acids, proteins, carbohydrates are not living but their complex compound protoplasm is a living substance. Also, it can multiply itself (here I mean it can produce more matter than that already given) or in simple words the substance grows. Still the compounds mentioned above cannot do so. So, what exactly is life? Please let me know what you feel about the distinction between living and non-living and how you think life grows.

Betelgeuse
2004-Oct-17, 08:42 AM
What is life?

There is no corresct answer. There's no specific answer. It's a theoretical question.

What is life? Why should we care? We are living things - it distinguishes us from most things in the universe.

Since life is such a ubiquitous and fundamental concept, the definitions of it are legion. —John D. Barrow and Frank J. Tipler, The Anthropic Cosmological Principle

There are so many every day notions, therefore can anything meaningful enough be said to define life?

You can see that one question clearly leads to many more.

Rigel
:D

astromark
2004-Oct-18, 02:12 AM
:huh: What is life ? Is it any cellular structor capable of reproducing or growing in a maner to sustain its self or reproduce itself. like plants, alge, single cell cretures. Microbic reproducing cellstructure sounds like the answer to me. Ask a microbioligest. The answer only gets confusing if you start trying to find scientiant beings. Things that think for them selves. I know of some people who dont do this....

StarLab
2004-Oct-18, 05:25 AM
Yes, but to elaborate a bit...life is anything that has a carbon backbone as the basic constituents of its organic compounds, and all things that can be classified as "living" have some sort of membrane...organelles, nuclei, selectively permeable lipid bilayers, etc...which is why viruses cannot be considered "living."

Victoria
2004-Oct-31, 12:16 AM
After coming across the subject...I instanty thought of Antartica...pink little one-celled organisms prospering in the sub-zeroes...thats what I think about life :)

GOURDHEAD
2004-Oct-31, 01:52 PM
Here (http://www.universetoday.com/forum/index.php?showtopic=1697&hl=cosmological+expansion) are some ideas about life.

In summary the valence charges of carbon, hydrogen, nitrogen, and oxygen are such that as they bounce around in the protostellar cloud, as well as in the later evolving more dense environments, they form ever more complex molecules leading to ever more selforganizing potential. The progenitor supernovae will have influenced this process by the ratio of these elements to each other and to the other life enhancing elements (Na, Cl, K, S, Ca, Ph, Fe, etc.,) present in a given cloud. The mindless, chaotic mixing of these elements by the electric, magnetic, and gravitational forces at play as the cloud shrinks to ever increasing densities thereby increasing the contact oportunities amongst them allows natural selection powered solely by the physics of relative valence charge strengths of the life supporting/enhancing elements to begin the march to the level of self organization that leads to self replicating molecules thence to life, ever increasing levels of consciousness, and technology.

astromark
2004-Oct-31, 09:12 PM
Originally posted by astromark@Oct 18 2004, 02:12 PM
:huh: What is life ? Is it any cellular structor capable of reproducing or growing in a maner to sustain its self or reproduce itself. like plants, alge, single cell cretures. Microbic reproducing cellstructure sounds like the answer to me. Ask a microbioligest. The answer only gets confusing if you start trying to find scientiant beings. Things that think for them selves. I know of some people who dont do this....
:rolleyes:
Life on this earth has taken very diferent paths, depending it would seem on the medium it is found in,. The depths of our oceans, those strange places near under sea volcanic vents. the extream cold of antartica to the deserts of africa. Life it would seem is prodigious, prolific, and determind to prevail. Its only a mater of time untill we find life on some place other than earth. Or it finds us :blink:

Victoria
2004-Nov-01, 01:10 AM
A little argumentative here G.H., I would go with sphinx on this one. Life is all around.

GOURDHEAD
2004-Nov-01, 03:39 AM
A little argumentative here G.H., I would go with sphinx on this one. Life is all around.

I agree. The process I hypothesized takes place in each cloud possesing the appropriate elements in the right range of ratios.

zephyr46
2004-Nov-01, 04:16 AM
What about stars?

I have read descriptions of neutron stars as dead stars, white dwarfs as reminents and brown dwarfs as failed stars.

It is only a small extension of the Gaia theory that the earth is a complex living organism that stars are a simple giant organism. The Supernova then becomes the process for stellar reproduction.

There are, I have heard Carbon rich stars (http://www.peripatus.gen.nz/Astronomy/CarSta.html). As far as lypids go, well, would a photosphere do?

ASEI
2004-Nov-01, 05:06 AM
A potential definition:

Life is a construct who's nature is to perpetuate its existence through actively sustaining and replicating itself. It does this by arranging whatever resources are at hand into equivalent constructs.

Because this definition is rather basic, some fuzzyness is present between what I consider alive and what I merely consider to be a spontaneous reaction (such as crystallization or fire). Perhaps this boundary can be better defined by including a condition that this reaction "life" would not happen in this medium under identical thermodynamic conditions were it not for the presence of that particular construct.

Betelgeuse
2004-Nov-14, 08:14 PM
Take a look at this (http://www.google.co.uk/search?hl=en&q=define%3A+life&meta=) - it shows exactly how many different definitions of life there are!

Tiny
2004-Nov-14, 08:36 PM
Life = the existence of matters

Spacemad
2004-Nov-14, 11:00 PM
Originally posted by astromark@Oct 31 2004, 09:12 PM

:rolleyes:

Life on this earth has taken very different paths, depending it would seem on the medium it is found in,. The depths of our oceans, those strange places near under sea volcanic vents. the extream cold of antartica to the deserts of africa. Life it would seem is prodigious, prolific, and determind to prevail. Its only a mater of time untill we find life on some place other than earth. Or it finds us :blink:

While it is extremely difficult to define exactly what life is we do know that it is ubiquitous & the so called "extremofilos" can be found in the most unexpected places as you enumerated, astromark. I especially liked this part of your post:

Life it would seem is prodigious, prolific, and determined to prevail. I think that is one of the greatest attributes of life - its ability to prevail even up against the greatest odds! :P

zephyr46
2004-Nov-15, 04:14 AM
So is a star a life form?

It has a life cycle, from its remanants, new stars are born, or you get Dwarfs, neutron stars and Black holes, so would they be Immortals? :blink:

GOURDHEAD
2004-Nov-15, 02:20 PM
So is a star a life form? It has a life cycle, from its remanants, new stars are born, or you get Dwarfs, neutron stars and Black holes, so would they be Immortals?
Perhaps the time has come to be more specific about what we mean by life. Most usage seems to refer to life capable of developing sentience such as the biological systems that evolved into us or supported our evolution in other ways such as being food for us or providing free oxygen for us to breathe. In its most broad generic usage we speak of the life of a contract, life of a bridge, life of a nation (which usage itself is fraught with many entendres), life of a star, life of a galaxy, and life of large episodes of development within the universe. In this broadest usage, context is the prime decoder of what we mean; whether we are refering to animate or inanimate objects, their span of duration, or a level of self-organization that allows the object to take willful action whether it is a microbe seeking food or critters like me seeking to control the configuration of large sections of the universe.

As for immortality, the pieces that make up stars, or us, are indeed "immortal" as surely as the principle of conservation of mass/energy is true, but how stars, or us, are configured is most certainly a transient condition.

If we mean other than biological life, including non-carbon based systems if such are found to exist, we should take the effort to make sure our intentions are clear.

Ola D.
2004-Nov-15, 02:22 PM
"What's life?" That's very confusing..
It depends from which perspective are you studying it, as it has many definitions according to the case you have.

A non-respiring human cell is dead according to the biological measures, at the same time a person with no ambitions and foresight can be considered dead too in a philosophical point of view.

It's a very general question with infinite probabilities when it comes to answering it :)

mercury
2004-Nov-17, 06:07 AM
This is a bit irrelevant but do you people know of any survey of population density taken throughout the world (esp. in the deep oceanic abyssal plains)? Also is it discovered how protoplasm is formed? Do you think there may have been conscious life on the Earth before humans?

mercury
2004-Dec-11, 09:59 AM
Why does the DNA structure have to possess a double-helix shape? Why does Adenosine stick to Thyamine and Guanine to Cytosine? Can robotic artificial intelligence be similar to consciousness?

Bobunf
2004-Dec-11, 05:21 PM
I think the standard definition of life runs something like this:

Life is an entity: 1. Which consumes, transforms, and stores mass and energy; 2. excretes waste; 3. Is part of a potentially indefinite system creating entities similar to itself, a system which is subject to mutation allowing for differential survival; 4. Is capable of responding to stimuli.

Mules and viruses count because they're part of a reproductive system.

Fire and computer viruses don't count because their reproductive systems arn't subject ot mutation allowing for differential survival.

Bob

Nyrath
2004-Dec-13, 07:19 PM
Erwin Shrödinger speculated that Life is That Which Feed On Negative Entrophy (http://dieoff.org/page150.htm). Though that might be a little too broad, as it would include both biological and computer viruses. It might also include fire and growing crystals.

StarLab
2004-Dec-14, 12:38 AM
Why can't we define life as anything with a definable protein structure?

aeolus
2004-Dec-14, 12:43 AM
..."is beautifal"? maybe that's just Hollywood's perception, though.

astromark
2004-Dec-14, 02:10 AM
Looking at this subject. I have conclouded that the computer is close to becomming a life form. with its own reproductive abilaty. powers of logic and abilaty to evolve. Yes I know that this will only happen if we want it to. But it will happen sooner than we are ready for.
'Thats odd! Look someone is building a fusion reactor in the middle of town, who could that be?'.....Oops. Resistance is futile.
Sorry for that, Its a bit silly, The defanition of Life is well enuff established. But what is intelagance?, and have I any...lol, or could I have some soon please.

Jakenorrish
2004-Dec-14, 10:23 AM
Hi all,

in the Hitchikers' Guide to the Galaxy, Douglas Adams speculated along the following lines. I'm going from memory, so forgive me for my inacuracy...

'There are those that speculate that when we discover the meaning of Life the Universe and Everything that the universe will instantly disappear and be replaced by something that makes even less sense and is even more bizarre......

There are also those who speculate that this has already happened!'

I'm in the latter camp!!

astromark
2004-Dec-14, 11:56 AM
All the diods in my left hand side are aching......Marvin.
Mmmm... no probebly not. So can you constrew the computer into a form of life.?

ChromeStar
2004-Dec-17, 07:59 PM
if we as humans are alive, then life might be defined as an entity that is living -meaning it follows the 7 fundamental rules that make a living organism growth, ingestion, egestion, reproduction, locomotion, ability to sense danger and suroundings and one more - but it should also be able to think, have a mind.

but that brings up 1 problem animals are alive, but we can't know atleast for now if they have a mind although dogs and dolphins might lead one to think they do!

Spacemad
2004-Dec-18, 07:07 PM
Originally posted by ChromeStar@Dec 17 2004, 07:59 PM

but that brings up 1 problem animals are alive, but we can't know at least for now if they have a mind although dogs and dolphins might lead one to think they do!
I can't vouch for dolphins, Chromestar, but we've got five little dogs & each one certainly does have a mind of its own! They can solve problems & each one knows the best way to manipulate its masters!!! :P

Tinaa
2004-Dec-18, 08:02 PM
In the current biology text we use, there are 7 characteristics of life as we know it:
1. Living Things are Composed of Cells
2. Living Things Have Different Levels of Organization
3. Living Things Use Energy
4. Living Things Respond To Their Environment
5. Living Things Grow
6. Living Things Reproduce
7. Living Things Adapt To Their Environment

Very few Plants have locomotion, yet they are alive.
What about about viruses?

Ola D.
2004-Dec-19, 05:41 PM
Why can't we define life as anything with a definable protein structure?
Possible, but that would only include the biological aspect.


Plants have no locomotion, yet they are alive.
What about about viruses?

--> Cell theory states that:
1. Cells are the building blocks of structure in living things
2. Cells are derived from other cells by division
3. Cells contain a blue-print (DNA) for their growth, development and behaviour
4. Cells are the site of all the chemical reactions of life (metabolism)

Viruses are an exception to the cell theory by having no site for metabolic reactions as they are Akaryotes; meaning that they have no nuclei or cell organelles. They only posses a genetic material and a complex protein coat.
Besides, viruses are non-living out of the host cell.

Note: Viruses don't reproduce, they replicate. Their multiplication process is referred to as "replication" because it's different than the other reproducing methods.

trevorsproston
2004-Dec-24, 06:31 PM
For plant locomotion, see David Attenborough's BBC series"Secret Life of Plants".

Ola D.
2004-Dec-25, 05:57 PM
Thanks Trevor, Do you have a link to the series?

PaPayA
2005-Jan-15, 10:22 AM
The word LIFE is also an illusion like the word CONSCIOUSNESS.......thats why we could not explain it..... we understand words with the help of pictures.... :lol:

ChromeStar
2005-Jan-16, 12:03 PM
Would you elaborate pls?