Talk:Life

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Since When is Life a Taxonomic Supergroup?

Just a question without a response. —Preceding unsigned comment added by 64.238.178.124 (talk) 21:30, 1 March 2009 (UTC)

Archiving talk

As a general rule, I would favor only archiving talk threads that have been quiet for a while, say a month. Exceptions can of course be made for persistent soap-boxers, etc, but even then some notice (? a week?) would be nice. Wwheaton (talk) 07:33, 23 December 2008 (UTC)

(--Faustnh (talk) 16:34, 18 January 2009 (UTC)). Hi. I would like to express I think Wwheaton is right. Particularly I'd like to express it would be better to archive a talk page when the extension of its content made it convenient.

Rest assured that the extension of its content was inconvenient. BatteryIncluded (talk) 05:46, 19 January 2009 (UTC)

(--Faustnh (talk) 15:24, 19 January 2009 (UTC)) .- Well, guess that was a good beginning.

Discussing definition

From the article:

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"There is no universal definition of life. To define life in unequivocal terms is still a challenge for scientists, and when derived from an analysis of known organisms, life is usually defined at the cellular level."

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Er... How about this one: life is a form of information that have found its way to survive

It correlates nicely with the physical characteristics [See 1]:

• feeds on negative entropy;
• continuous systems able to decrease their internal entropy;
• DNA/RNA is just information;
• cultural heritage is just information;
• etc...

It includes viruses and every other possible 'living creature'. It gives nice definition of evolution - based on entropy. It even gives the definition of the 'intelligent life' - one that can formulate a clear definition of the term :)

--Mitra (talk) 07:31, 17 January 2009 (UTC)

P.S. Support that definition and become the very few first species of the 'intelligent human life' on the planet :)

P.P.S. The idea is definitely NOT O.R. See No_original_research, "The "No original research" rule does not forbid routine calculations ....."

P.P.P.S. Regard the GNU_Free_Documentation_License ;) —Preceding unsigned comment added by M i t r a (talk • contribs) 08:11, 20 January 2009 (UTC)

I have re-ordered the above addition, in line with the standard talk-page system of putting later threads last. Then if later comments come in on earlier threads, the only defense against hopeless confusion (that I know at least) seems to be careful indentation and rigorous signing & date-stamping of posts.

I do support the general notion that this article needs to be broadened beyond the "cell-chauvinistic" position previously advocated by User:BatteryIncluded (see the /Archive 3). I think there is ample place to discuss cell biology and microbiology in Wikipedia already, while this article should (besides surveying traditional Earth biology) at least try to address the physical and philosophical issues involved in the definition in terms of function, and mention broader proposed extensions that are not arbitrarily tied to a particular chemical or physical substrate. As we begin to escape from our terrestrial environment, we may encounter life forms that are really different that earthly cellular life. How are we to recognize those, deal with them, and value them? Without some more extensive prior thought we could just dismiss them as "rocks" and grind them up to make toasters or Barbie Dolls. (If they do not do something similar to us first, of course.) Even on Earth, we encounter borderline bioforms, such as viruses, prions, and superorganisms that do not fit the cellular model, but which are clearly biological. Technology also is leading us swiftly to systems that behave more and more like "life" but do not yet clearly qualify. I agree that the fundamental issues seems to revolve around information and entropy.

In my opinion none of the above suggestions by Mitra, or me, or others can go into article space itself without reliable sources because of our original research disciplines, which appear absolutely necessary to this enterprise. However there is such a literature, as referenced in Living systems and Living systems theory, Thermoeconomics, going back at least to James Grier Miller's seminal paper in 1978, Schroedinger's famous 1944 book What Is Life? and probably well before. Some of this is already mentioned in the references and the "See also" links. (My own background is in physics, so I am not well-qualified in these areas, and hoped to find more expert information here.)

The discussion of what is known and published in the literature, and how it might best fit into this article (or perhaps spin off a separate article on definition?), seems to me to be valid material for our talk page. Wwheaton (talk) 02:13, 18 January 2009 (UTC)

We can make up definitions, the fact remains that they are original "research". The universal scientific consensus is that the cell is the basic unit of life. It is not "chauvinistic", it is simply that angels and invisible galactic pink unicorns are not available for analysis. I personally have faith in the Gaia hypothesis, but if each of us begin to write about our own faith, beliefs on "living rocks", living sotware, etc., the article will degrade in quality and usefulness. Fringe theories can be interesting and even catalysts for research, yet they are beyond the scope of Wikipedia. However, experts in astrobiology are quite aware that hypothetical extraterrestrial life could be different from what we know. Astrobiology programs are -of course- questioning how we can detect extraterrestrial life if different from ours. Astrobiologists are not inside a laboratory bubble as you want us to believe. For example, NASA’s Astrobiology Program addresses three fundamental questions: How does life begin and evolve? Is there life beyond Earth and, if so, how can we detect it? What is the future of life on Earth and in the universe? [1]. There are at least other 2 or 3 formal astrobiology programs, and all are asking the right questions.... all outside of the box, and indeed, they make use of philosophy as their noble premises are largely hypothetical. Until we come across an extraterrestrial living rock, an angel or a galactic invisible pink unicorn, all forms of life identified so far by science are terrestrial, physical, and cellular. BatteryIncluded (talk) 03:14, 18 January 2009 (UTC)

Thanks, I hope I see your point, yet I am not sure. I do not see a definition as "research", only as a proposed meaning for a word, which may or may not become accepted as useful. I know the status of viruses as life is somewhat controversial, but I was unaware that it was settled dogma, or universal consensus. And what about superorganisms? They are not cells, but are they a kind of organism? (If not, why are sponges or people organisms?) Would you then deny the possibility of our encountering a non-cellular life form, on or off the Earth? Is astrobiology by definition limited to searching for cellular life? If we we were to encounter something that preserves and reproduces its core information content, metabolizes and processes energy to enable it to hold off the Second Law, and manipulates its environment to its advantage, would we then deny the possibility of it being life if it were non-cellular? (Perhaps homeostasis is the key issue here? Your cells actively maintain an internal environment, whereas a virus does not, or barely does.)

Forgive me for not deferring to you obviously greater expertise, but I do believe there is some respectable literature supporting my questions about these issues. Cheers, Wwheaton (talk) 04:20, 18 January 2009 (UTC)

Uh. It's interesting how you've started talking about 'beliefs' right away. And I don't mind that at all. People beliefs ARE important and maybe we can find a place in the article describing some common ones. On the other side though stays scientific definition, and it's department of logic, not beliefs. There are obviously several most common definitions, with the biological leading the way. And lets keep it that way; only lets call it what it is -- 'biological definition of life'. --Mitra (talk) 17:30, 18 January 2009 (UTC)

To BatteryIncluded. It's very difficult to use your comments. Not logical, not NPOV, O.R., mixed with your personal beliefs. Even the phrase: "The universal scientific consensus is that the cell is the basic unit of life." - says who?! The 'universal board of science?!?'. And the rest of your comment is entirely your personal beliefs. Please keep NPOV. --Mitra (talk) 21:47, 18 January 2009 (UTC)

Gentlemen, under yor proposed definition, an ancient cave painting that survived time, erosion and humidity would be considered alive. Please feel free to go back to the drawing board. Better yet, why reinvent the wheel? What is the centuries-old scientific discipline in charge of studying and describing life?: Biology. So let's consider instead what biologists have brough forth so far. Regarding non-cellular life (excluding virus), there is no evidence of it, yet astrobiologists are open to notice its different possible manifestations. The day an invisible galactic pink unicorn or talking fire-ball crosses the path of earthlings, then hopefully we will notice its particular biology and sure enough, a new definition of life will be formulated, based on the observed phenomena. Although the world convention is that the basic unit of life is the cell, biologists have not agreed on a definitive definition of it; never mind trying to define hypothetical organisms we don't even know or may not even exist. The problem with your making a definition so wide and general so that everything gets included "just in case", is that such definition would have no practical usefulness. Now if it is religion you want to discuss, (soul, god, angels, demons, satan, heaven, hell, salvation, damnation, ghosts, holly ghosts, etc.), there are several religious and faith-related articles dealing with their empirical perception of life and spirituality. If it is creationism/intelligent design, there are articles on that too. If it is natural science and biology, e.g: the study of life, I am in. Cheers, BatteryIncluded (talk) 22:51, 18 January 2009 (UTC)

"under your proposed definition, an ancient cave painting that survived time, erosion and humidity would be considered alive". -- This is correct. But the entropy here is going to be quite high. And the amount of information - very low. Usefulness: clear, almost mathematical definition can be useful. And it is natural science and biology that I like to discuss here, not beliefs or religion. --Mitra (talk) 01:26, 19 January 2009 (UTC)

On the other hand any biological 'system' is immensely complex, the amount of information high and entropy quite low. --Mitra (talk) 01:39, 19 January 2009 (UTC)

Well, of course my suggestion started by saying that life has a kernel of core information, which it reproduces (fairly) faithfully. That excludes cave paintings. By reproducing its information core, it actively organizes its surrounding materials, which requires free energy G, and thus metabolism. This is physics and chemistry, nothing spiritual suggested (meant without prejudice). Saying life is necessarily "cells", without a physical definition of the term, seems to me to hark back to vitalism, almost; though I would not accuse BatteryIncluded of that heinous sin. (But I would appreciate it if you, my learned friend, would drop the pink unicorns.) I admit if I actually encountered pink ghostly unicorns that satisfied my physical criteria (cruelly archived, alas; anyone who is interested can look near the end of /Archive 3), especially if these critters had a large ratio of core information kernel size to environmental information content, then I suppose I would have to at least consider the possibility that they might qualify as alive.

Anyhow, I still think cells are good examples of life, but not necessarily a good definition of life. And I think we are approaching a level of awareness where it would behoove us to think hard about what the real physical and chemical qualifications might be that distinguish life from non-life. My proposal makes a stab at defining a number, the ratio of kernel to environmental information content, according to which candidates might be classified and ranked—without being too committal yet as to what the threshold value should be, or if there should even be a definite threshold. I do not really think this idea can be original, but I had hoped (and still do hope) that some of the more expert people interested in this subject might provide useful guidance, and perhaps entree to the relevant literature, either for correcting and refining my idea, with a view to strengthening this article, or conceivably starting a new one. KILLING the idea off decently, entirely, would of course be OK, but I am not yet convinced that has been done. Cheers, Wwheaton (talk) 02:48, 19 January 2009 (UTC)

Er.. Wwheaton. FYI - cave paintings have their peculiar way of reproduction and evolution. Apparently you need an ape to copy and spread one. --Mitra (talk) 03:18, 19 January 2009 (UTC)

Good point. The cave man is part of the environment for the "Painting Life" to grow, and he has a lot of information in him, more than the painting itself, so the information ratio would be very small, thus I would call it "not very lifelike". Cheers, Wwheaton (talk) 03:36, 19 January 2009 (UTC)

Er.. would you call information "not very informationlike" if the number of bits is to few? --Mitra (talk) 03:53, 19 January 2009 (UTC)

Look at this cave painting [2]. It's fascinating to estimate just how much information (life) have been just transferred from that ape to you. And how it will evolve. --Mitra (talk) 04:28, 19 January 2009 (UTC)

See Nealson KH, Conrad PG (1999). "Life: past, present and future" (PDF). Philos. Trans. R. Soc. Lond., B, Biol. Sci. 354 (1392): 1923–39. doi:10.1098/rstb.1999.0532. PMC 1692713. PMID 10670014. {{cite journal}}: Unknown parameter |month= ignored (help) hopefully a useful intro to the literature. Tim Vickers (talk) 02:53, 19 January 2009 (UTC)

Hey, thanks! This is helpful. (And still cells, BI!) BTW, let's resolve that if our argument just goes around in circles, we take it to our personal talk pages, OK? Wwheaton (talk) 03:36, 19 January 2009 (UTC)

The way to solve the problem is to put your own opinions to one side and just summarise what the sources say on the topic. Our own ideas have no relevance or use, we have to report what the sources say - and nothing more. Tim Vickers (talk) 04:29, 19 January 2009 (UTC)

Of course the referenced paper deals with cells. Could it be that ...... cells are the basic unit of life? This discussion reminds me of a child trying to fit a trianglular block inside a circular hole. You can't discuss bilogy and mix fantasy so that one day you may be proven right. There is no evidence of non-cellular life (viruses got a debatable pass), so it can't be included. On the other corner, an editor here believes that entropy is the magic word that would vest almost any object with life. Energy by itself is not enough; it has to be expressed in a physical form (matter) and carry on with complex biochemical pathways that support the structural and functional elements of metabolism, homeostasis, reproduction, etc. To be fair, it is a tough enterprise to formulate a definition of life; it is relatively easier to describe its observable phenomena. Finally, I am glad the pink unicorns got archived, and regarding the information kernel ratio thing, I have 2 leters: OR. I agree with Tim Vickers, report what the reliable sources say - and nothing more. Cheers, BatteryIncluded (talk) 04:36, 19 January 2009 (UTC)

Thank you, TimVickers. But your comment is a bit off-topic on this discussion page. Not to mention, that if you follow your own logic, your own message have no relevance or use. I would also suggest reading No_original_research policy. It almost explicitly says - it's OK to think for yourself and summarize!!! --Mitra (talk) 04:44, 19 January 2009 (UTC)

BatteryIncluded.... I'm only using logic and proven facts and summarize them. I agree with you, that from the biology perspective "cells are the basic unit of life" would be a true statement. But would you agree that RNA is just information? And that neat, almost mathematical definition of any term is the best one? --Mitra (talk) 04:51, 19 January 2009 (UTC)

Which sources use this mathematical definition that are you referring to Mitra? Tim Vickers (talk) 05:10, 19 January 2009 (UTC)

TimVickers, I've only used logic and summarized information in the original Life article. No O.R. No external references. --Mitra (talk) 06:44, 19 January 2009 (UTC)

Dear Mitra, your statements are extremely flawed. There is nothing mathematical about it, and RNA is not "just information". For homework, please find out the functions of tRNA, rRNA, mRNA and snRNA. Reagarding your response to Tim Vickers, i disagree with you; Tim's response is at the very heart of what Wikipedia is, and it brings about guidance (e.g: a stop) to the conjectures and ill "definitions" some intend to include in this article. Cheers, BatteryIncluded (talk) 05:23, 19 January 2009 (UTC)

BatteryIncluded, again I can't find any logic in your assertion. Random biological terms. I do know, for instance, the function of tRNA - Transfer RNA. What it does in terms of the cellular machinery. But being professional you should know what it does in terms of the information transfer from one part of the cell to another! As to my response to Tim, again, I've only used logic. --Mitra (talk) 06:44, 19 January 2009 (UTC)..... edit... My mistake. I've messed up tRNA with mRNA. --Mitra (talk) 17:59, 20 January 2009 (UTC)

You flunked to the abyss. I see now where you stand. Dispense with your "logic" and dig some referenced material. Cheers, BatteryIncluded (talk) 07:00, 19 January 2009 (UTC)

BatteryIncluded, again I can't find any logic in your [random] assertion. Your statement is also irrelevant and personal. It does not sound professional as well. Please refer to Personal_abuse for more information on that. --Mitra (talk) 07:26, 19 January 2009 (UTC)

I can also find links: Please refer to WP:NOTFORUM for more information on ramblings. Cheers, BatteryIncluded (talk) 08:01, 19 January 2009 (UTC)

Uh. Thanks. Point taken. Exactly my point :) --Mitra (talk) 08:48, 19 January 2009 (UTC)

Is that the abyss of biologists with good intentions, the kind that use abbreviations meaninglessly? --Mitra (talk) 17:47, 20 January 2009 (UTC)

Trolling (WP:DFTT) refers to deliberate and intentional attempts to disrupt the usability of Wikipedia for its editors, administrators, developers, and other people who work to create content for and help run Wikipedia. The basic mindset of a troll is that they are far more interested in how others react to their edits than in the usual concerns of Wikipedians: accuracy, veracity, comprehensiveness, and overall quality. If a troll gets no response to their spurious edits, then they can hardly be considered a troll at all. BatteryIncluded (talk) 18:41, 20 January 2009 (UTC)

At an everyday practical level the links between information entropy and thermodynamic entropy are not close. Physicists and chemists are apt to be more interested in changes in entropy as a system spontaneously evolves away from its initial conditions, in accordance with the second law of thermodynamics. I realize your account in Wikipedia, Mitra, is of a single-purpose user, so I will not invest any more time trying to explain to you the pilars of Wikipedia and the need to report only what the sources say, instead of pushing your own perceptions, logic, interpretations, agenda and OR. BatteryIncluded (talk) 16:54, 19 January 2009 (UTC)

--Mitra (talk) 17:33, 19 January 2009 (UTC)

Sorry for my childish behavior. If I've created any inconvenience for you or any other Wikipedian, I apologize here. Please forgive me. --Mitra (talk) 16:27, 22 January 2009 (UTC)

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--Faustnh (talk) 20:31, 19 January 2009 (UTC)

Recursiveness \ self-dependence \ self-benefitting is a foundational and causal condition of biological process.

Biological activity's main expressions barely add something new to that causal condition, for the definition of life.

My appreciation is positively coincident with Wwheaton's argument. Cell theoretical approach is incidental and the article should give the concept of Pre-cellular Life a more relevant position.

I would reduce the seven conventional sub-definitions treated by the article, to the following four main biological sub-functions:

> Nutritional \ Metabolic extension of biological recursiveness \ self-dependence \ self-benefitting : (i.e. Pre-Cellular Life) this is an "inward self-regeneration" or "inward self-replication".

> Reproductive \ Dividual extension of biological recursiveness \ self-dependence \ self-benefitting : (i.e. Cellular Life) this is an "outward self-regeneration or self-replication". (We would include here Evolution, that is, (Re)Adaptive Transformation, as Mutation is not an accident for reproduction, but a causing foundation; Reproduction should not be seen as repetition, but as variation).

> Mutualism and Meta(Hyper or Super)Mutualism extensions of biological recursiveness \ self-dependence \ self-benefitting : (i.e. Multi-Cellular Life) instances of this are social manifestations, symbiosis, food-chains, chemical cycles and hypercycles (cyclical or mutual interdependences), enzyme catalysis, superorganisms, etcetera. This is another biological strategy of defense or protection, respecting environmental factors. Environment and environmental diversity, causes biological diversification. But life tends to self-organize in successive orders or layers of sets and metasets (or hypersets).

> Technological (wide sense) extension of biological recursiveness \ self-dependence \ self-benefitting : (i.e. Animal Life) this is how living organisms change their environment, to make it more favorable and beneficial to living organisms themselves. Or, in other words, this is how living organisms take part actively in their own preservation, respecting environmental conditions.

(PD: anyway I understand and assume that Wikipedia wants to be a secondary source, and wants to avoid the question of evaluating if some theoretical approaches are worse or better than others ).(--Faustnh (talk) 20:53, 19 January 2009 (UTC))

From WP:NOR

Wikipedia does not publish original research or original thought. This includes unpublished facts, arguments, speculation, and ideas; and any unpublished analysis or synthesis of published material that serves to advance a position. This means that Wikipedia is not the place to publish your own opinions, experiences, or arguments. Citing sources and avoiding original research are inextricably linked: to demonstrate that you are not presenting original research, you must cite reliable sources that are directly related to the topic of the article, and that directly support the information as it is presented.

No original research is one of three core content policies. The others are neutral point of view and verifiability. Jointly, these policies determine the type and quality of material that is acceptable in articles. Because they complement each other, they should not be interpreted in isolation from one another, and editors should familiarize themselves with all three.

If you have original research or commentary to contribute to a subject, there are numerous other places to do so, such as at WikiInfo.

BatteryIncluded (talk) 21:28, 19 January 2009 (UTC)

Respiration

ADD: That there is another characteristic of life - RESPIRATION. Please insert this into the page. —Preceding unsigned comment added by KWMec (talk • contribs) 19:12, 15 March 2009 (UTC)

Cellular respiration: A series of metabolic processes that take place within a cell in which biochemical energy is harvested from organic substance (e.g. glucose) and stored as energy carriers (ATP) for use in energy-requiring activities of the cell.

It is a subset of metabolism, which is already included. [3]. Cheers, BatteryIncluded (talk) 19:24, 15 March 2009 (UTC)

Question on Conventional Definition of Life

Based on the language used in the article, it was not entirely clear to me what the phrase "Also, individual members of a species may not meet all the criteria, but are still considered alive, such as members of a species who are rendered unable to reproduce or unable to respond to stimuli" means exactly. Does this mean to imply that, if one was using the conventional definition list, that the only two exceptions that can exist and still allow something to be called life are reproduction and response to stimuli? Or does the use of the words "such as" mean more along of the lines of "for example"? To be more precise, what I mean is are any of the seven items on the list absolutely required for something to be deemed life? Any help would be greatly appreciated. Thanks guys.

71.236.90.132 (talk) 08:13, 27 March 2009 (UTC)