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Author Topic:   Life - an Unequivicol Definition
AlphaOmegakid
Member (Idle past 2107 days)
Posts: 564
From: The city of God
Joined: 06-25-2008


Message 16 of 374 (772365)
11-12-2015 6:27 PM
Reply to: Message 15 by Tanypteryx
11-12-2015 6:02 PM


tany writes:

This is really only the case for sexually reproducing species. Asexually reproducing species like many bacteria and other single celled organisms can and do evolve when mutations occur in individual organisms.

And while populations evolve, the mutation part of evolution occurs in the sex cells of individuals.

Try spending five minutes here: https://www.google.com/?gws_rd=ssl#q=populations+evolve+i...

and maybe what flew over my head should fly out of yours!?!


This message is a reply to:
 Message 15 by Tanypteryx, posted 11-12-2015 6:02 PM Tanypteryx has replied

Replies to this message:
 Message 17 by Tanypteryx, posted 11-12-2015 7:36 PM AlphaOmegakid has replied

  
Tanypteryx
Member
Posts: 3279
From: Oregon, USA
Joined: 08-27-2006
Member Rating: 3.1


(1)
Message 17 of 374 (772370)
11-12-2015 7:36 PM
Reply to: Message 16 by AlphaOmegakid
11-12-2015 6:27 PM


Try spending five minutes here: https://www.google.com/?gws_rd=ssl#q=populations+evolve+i...
and maybe what flew over my head should fly out of yours!?!

If you have an argument to make, make it. We do not debate bare links here.

It just appears to me that you misunderstood part of what RAZD said. I don't think he was saying that individuals are the only unit of evolution.

Individuals are the unit of reproduction. They pass on the mutations that are selected for or against by the environment.


What if Eleanor Roosevelt had wings? -- Monty Python

One important characteristic of a theory is that is has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie

If evolution is shown to be false, it will be at the hands of things that are true, not made up. --percy


This message is a reply to:
 Message 16 by AlphaOmegakid, posted 11-12-2015 6:27 PM AlphaOmegakid has replied

Replies to this message:
 Message 37 by AlphaOmegakid, posted 11-17-2015 5:42 PM Tanypteryx has replied

  
Blue Jay
Member (Idle past 1928 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


(2)
Message 18 of 374 (772372)
11-12-2015 9:21 PM
Reply to: Message 14 by AlphaOmegakid
11-12-2015 5:47 PM


Hi, AOkid.

AlphaOmegakid writes:

Yes, I understand, that’s your training. That’s what I meant by indoctrination.

I was talking about ecologists specifically, not about all biologists. And it isn't really indoctrination: it's experience with a frustratingly complex and chaotic subject matter. The rest of biology doesn't have the same problem: genomics, for example, has a lot of highly quantifiable mechanisms that can be readily isolated and characterized in the lab.

AlphaOmegakid writes:

Blue Jay writes:

This is mainly because the systems we try to study are inherently more complex than we can replicate with experiments or models.

Yet some can model climate change with authority! Hmmmmm?

As difficult and complex as climate is, it's still much more tractable and predictable than ecology. Consider that climate is actually one of the explanatory variables in ecology, so that an accurate prediction of future ecological dynamics would necessarily incorporate a climate model as one component.

AlphaOmegakid writes:

Needlessly specific??

Yes, needlessly specific. You're trying to define life in terms of a specific chemistry, when we don't really know that life couldn't exist on alternative chemistries. I suggested a hypothetical life-form that uses GTP instead of ATP. The two molecules are chemically very similar, and store the same amount of energy --- there's no reason why a metabolism couldn't exist that uses GTP.

If such an organism were discovered, would you entertain the notion that it wasn't alive, just because it doesn't fit your definition?

AlphaOmegakid writes:

Regarding the tautology , yes I know what one is, but I don’t see how you are applying it. Shed some light in this darkness!

You said "this definition encompasses all known life." Since "life" is what the definition defines, this statement is true regardless of what the definition actually is.


-Blue Jay, Ph.D.*

*Yeah, it's real

Darwin loves you.


This message is a reply to:
 Message 14 by AlphaOmegakid, posted 11-12-2015 5:47 PM AlphaOmegakid has replied

Replies to this message:
 Message 38 by AlphaOmegakid, posted 11-17-2015 6:05 PM Blue Jay has replied

  
Dr Adequate
Member (Idle past 282 days)
Posts: 16112
Joined: 07-20-2006


Message 19 of 374 (772373)
11-12-2015 10:15 PM
Reply to: Message 7 by Blue Jay
11-12-2015 1:39 PM


I think you might be wrong about this. If we were to poll biologists with the question --- "What is the definition of 'life'?" --- I suspect that an "any of the above" or "it depends" option would be a very popular one.

And yet those who said that would not be equivocating. As I said: "Some of them say YES, some of them say NO, some say that they haven't made up their minds yet, but none of them equivocate."


This message is a reply to:
 Message 7 by Blue Jay, posted 11-12-2015 1:39 PM Blue Jay has replied

Replies to this message:
 Message 29 by NoNukes, posted 11-13-2015 4:16 PM Dr Adequate has taken no action
 Message 40 by AlphaOmegakid, posted 11-17-2015 6:23 PM Dr Adequate has replied
 Message 46 by AlphaOmegakid, posted 11-18-2015 8:47 AM Dr Adequate has replied
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dwise1
Member
Posts: 5062
Joined: 05-02-2006
Member Rating: 2.7


(2)
Message 20 of 374 (772377)
11-13-2015 1:02 AM
Reply to: Message 1 by AlphaOmegakid
11-12-2015 10:32 AM


When I see people wanting to create "unequivocal definitions", I get nervous. As I imagine myself saying in such real-life exchanges, "Dammit, Jim! I'm an engineer, not a philosopher!" Nor a lawyer. Nor a theologian. Nor any other profession or hobby which plays at redefining reality with definitions.

And I get nervous at such shenanigans because I just know that that philosopher/lawyer/theologian/charlatan is about to pull off a scam.

Now, on the operational level (eg, working engineers and scientists and craftsmen and cooks, etc), we need to define what we are working with based on their actual properties. Furthermore, we need to create definitions that allow us to distinguish between things that are different, especially where that difference makes a difference. But regardless of what names and definitions we give things, reality will tick along exactly the same.

But philosophers/lawyers/theologians/charlatans see definitions differently. They see themselves performing a form of Word Magick in which their new definitions actually change reality. They are ever ready to define reality out of existence.

Biologists are struggling with figuring out what life is. AOK wants to arbitrarily pronounce what is alive. It's like the creationist claims about whether something is a new species. The transition from one species to another takes many generations. Between which two generations do you draw the Line of Demarcation? It's arbitrary. There is even such a thing as a "species problem" in which we try to define whether two populations are of the same or different species. The inability to interbreed is often cited as the criterion for determining that, and yet many closely related species that are definitely different species are still able to interbreed.

I once read some book about sex (over a span of nearly half a century, I cannot be held accountable for being more specific) that sex is not nice and neat, but rather very wet and very messy. Therefore, life itself is infinitely wetter and infinitely messier. How could you possibly tie all that up in a neat little definitional package with a pretty little bow?

One of the founders of the Intelligent Design Movement, Phillip Johnson, is a lawyer. I first encountered him on Nova one night (his book, "Darwin on Trial", was mentioned. It was published in 1991, yet my memory places that episode prior to 1982, so I must assume that my rather vivid memory is faulty here). The argument he was presenting then was that Darwinism violates the rules of evidence for court proceedings. My immediate mental response was, "What an idiot! Science is not a court trial, but rather a police investigation!"

Working scientists create working definitions with which to work. Those working definitions may not be rigorous enough to satisfy arm-chair reality shifters, but they do serve the purposes of the research being conducted.

Ultimately, the problem with any definition is how it can deal with the myriad exceptions. For example, at the local US Marine Corps air station, our Cub Scout pack was given presentations and demonstrations about fire fighting and disaster preparedness. A common part of military fire-fighting training is to present Fire as Living. The trainer lists qualities of life and "shows" that fire displays those qualities of growing and consuming, etc (hey! that was more than two decades ago!). While not binding for biology, it does seem to serve the purpose of instilling a mindset in a firefighter that fire is something that will try to outsmart him.

So then, AOK, just what are you trying to define out of existence through your Word Magick?


This message is a reply to:
 Message 1 by AlphaOmegakid, posted 11-12-2015 10:32 AM AlphaOmegakid has replied

Replies to this message:
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dwise1
Member
Posts: 5062
Joined: 05-02-2006
Member Rating: 2.7


Message 21 of 374 (772378)
11-13-2015 1:06 AM
Reply to: Message 10 by RAZD
11-12-2015 3:54 PM


Mine is simpler: anything capable of evolution. (cue definition of evolution ^(1)... ).

Since evolutionary processes require some mechanism for replication (whether self- or otherwise), that would make the ability to replicate a defining characteristic of life.

This message is a reply to:
 Message 10 by RAZD, posted 11-12-2015 3:54 PM RAZD has replied

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Pressie
Member
Posts: 2102
From: Pretoria, SA
Joined: 06-18-2010


Message 22 of 374 (772384)
11-13-2015 7:14 AM
Reply to: Message 20 by dwise1
11-13-2015 1:02 AM


dwise1 writes:

Working scientists create working definitions with which to work.

Yes, working definitions. In my field an example is the delta forming at Oranjemund. It's been forming for and changing for millions of years.

The depositional environment works for diamond exploration in that area, but won't work in the Mississipi Delta. The processes for diamond deposition are not favourable in that Mississipi area. No Kimberlites of the right ages around around!

Maybe that's the creationist problem? They don't realise that different conditions apply in different circumstances? To me it seems as if their problem is that they don't know anything about basic science though they pretend to do it? But, when they think that everything was poofed into existence in one shot they really are not even open to contemplate reality? Hence their insistence on one definition for everything?


This message is a reply to:
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RAZD
Member (Idle past 636 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 23 of 374 (772387)
11-13-2015 8:32 AM
Reply to: Message 21 by dwise1
11-13-2015 1:06 AM


Mine is simpler: anything capable of evolution. (cue definition of evolution ^(1)... ).

Since evolutionary processes require some mechanism for replication (whether self- or otherwise), that would make the ability to replicate a defining characteristic of life.

Replication (with inheritable errors) is a part of evolution, but crystals replicate (without inheritable errors).

Enjoy


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
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Replies to this message:
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Dr Adequate
Member (Idle past 282 days)
Posts: 16112
Joined: 07-20-2006


Message 24 of 374 (772388)
11-13-2015 9:01 AM
Reply to: Message 23 by RAZD
11-13-2015 8:32 AM


I think his point is that in that case mules aren't alive.

This message is a reply to:
 Message 23 by RAZD, posted 11-13-2015 8:32 AM RAZD has replied

Replies to this message:
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RAZD
Member (Idle past 636 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


(1)
Message 25 of 374 (772389)
11-13-2015 9:15 AM
Reply to: Message 13 by AlphaOmegakid
11-12-2015 5:40 PM


Look at your definition. You of all people should know better than this! Populations evolve, not individual organisms. So by you definition, only populations are alive, because only populations are capable of evolving. Individual entities cannot be alive, because individuals do not evolve. I guess you just died. I don't think you will get too far with that one in the science community. But then again maybe you will!

Agreed.

Populations are indeed alive and constantly changing and indeed evolving; you can also view species as individual organisms that compete for fitness with other species in being able to survive and reproduce (with unfit species becoming extinct). Ant colonies as a single entity, for example, but applicable to all species. This is a macroevolutionary view, and if we take your argument to it's logical terminus, then we have to consider that this definition of life only applies to all of life as one complete unit. Life is what lives.

But curiously, not only (as has already been pointed out) are asexual organisms capable of being a population of one that evolves, that isn't the only point regarding individuals within a population. Multicellular organisms -- like us -- are composed of many many many individual cells, some dying (skin cells in particular) some being formed by cell division, but not pure clones of other cells, they have their differences. The cells in your body are completely exchanged\replaced over a period of years (~10 years on average iirc), so you are like those 'macroevolutionary level species organisms' that are composed of individuals -- you are composed of individual cells that go through the process of evolution, you are (like a colony of ants) a (colony) population of cells, and so yes, you are living by my definition.

You can even go further and consider a multicellular organism to be an ecology composed of several different species of cells that sometimes live in peaceful coexistence and sometimes compete with other groups for fitness within the ecology.

Enjoy

Edited by RAZD, : .

Edited by RAZD, : ..


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
to share.


• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

This message is a reply to:
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Blue Jay
Member (Idle past 1928 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


(1)
Message 26 of 374 (772399)
11-13-2015 12:03 PM
Reply to: Message 10 by RAZD
11-12-2015 3:54 PM


Hi, RAZD.

RAZD writes:

Mine is simpler: anything capable of evolution. (cue definition of evolution ^(1)... ).

...

(1) The process of evolution involves changes in the composition of hereditary traits, and changes to the frequency of their distributions within breeding populations from generation to generation, in response to ecological challenges and opportunities for growth, development, survival and reproductive success in changing or different habitats.

Perhaps this is a nitpick, but the simplicity of your definition is an illusion. All you've really done is obscure the complexity of it behind a footnoted definition for "evolution." In all fairness, you should include the footnote as part of your definition, because without it, languages and stars,, which are also said to "evolve," can also be considered "life."

If we do that, here's what the definition looks like:

Anything capable of changes in the composition of hereditary traits, and changes to the frequency of their distributions within breeding populations from generation to generation, in response to ecological challenges and opportunities for growth, development, survival and reproductive success in changing or different habitats.

When phrased like this, it's pretty clear that "life," as you define it, has at least three fundamental characteristics: (1) hereditary traits, (2) a population, and (3) the ability to experience changes in the distribution of hereditary traits within the population in response to... etc.

If we look a little closer, we can see that "hereditary" presupposes reproduction, and "traits" presupposes organization. "Reproduction" and "organization" are two of the classical characteristics of life. So, "hereditary traits" is sort of just a glossed-over paraphrasing of a more substantive definition.

In fact, we can further evaluate your entire definition and conclude that it's basically just an obscurantist repackaging of the "classical" description of life:

Life is organized; it responds to stimuli, metabolizes energy, grows, reproduces, and adapts.

Simplicity is nice, but clarity is better.


-Blue Jay, Ph.D.*

*Yeah, it's real

Darwin loves you.


This message is a reply to:
 Message 10 by RAZD, posted 11-12-2015 3:54 PM RAZD has replied

Replies to this message:
 Message 28 by AZPaul3, posted 11-13-2015 2:52 PM Blue Jay has seen this message
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JonF
Member
Posts: 6174
Joined: 06-23-2003


(1)
Message 27 of 374 (772403)
11-13-2015 12:58 PM


I've always liked "Life is that which dies when you stomp it".

  
AZPaul3
Member
Posts: 6630
From: Phoenix
Joined: 11-06-2006
Member Rating: 3.1


Message 28 of 374 (772408)
11-13-2015 2:52 PM
Reply to: Message 26 by Blue Jay
11-13-2015 12:03 PM


The problem I see with this definition is it doesn't get basic enough. The lone last survivor of Homo ergaster, doomed for sure, is still "life" though not by this definition since she has no capacity to reproduce and adapt. I will assume that by reproduction we are talking in species and by adapt we're not talking about donning a deer hide when it gets cold.

Though AlphOmegskid's definition seems quite good for Earth-based life it does leave out viruses and, most probably, anything non-terrestrial.

The old example of someone on an alien world curious about a rock lying on the surface only to watch it scamper away as he approaches. No details of chemistry or population dynamics but the instant presumption of "life" none the less.

My favorite definition of life is complex chemistry in continuous motion. This leaves plenty of big holes and is not adequate by any means. That vat of fermenting beer in the basement qualifies (and maybe not that far wrong come to think about it) and it takes a stretch to include the dormant stage of a virus, but it is the best definition I have found.

Edited by AZPaul3, : No reason given.

Edited by AZPaul3, : No reason given.


This message is a reply to:
 Message 26 by Blue Jay, posted 11-13-2015 12:03 PM Blue Jay has seen this message

  
NoNukes
Inactive Member


Message 29 of 374 (772417)
11-13-2015 4:16 PM
Reply to: Message 19 by Dr Adequate
11-12-2015 10:15 PM


And yet those who said that would not be equivocating.

I thought about this just a bit. I am having difficulty imagining how "it depends" would not be an equivocating answer. What would be an equivocating answer?


Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)

History will have to record that the greatest tragedy of this period of social transition was not the strident clamor of the bad people, but the appalling silence of the good people. Martin Luther King

If there are no stupid questions, then what kind of questions do stupid people ask? Do they get smart just in time to ask questions? Scott Adams


This message is a reply to:
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RAZD
Member (Idle past 636 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 30 of 374 (772460)
11-14-2015 12:49 PM
Reply to: Message 24 by Dr Adequate
11-13-2015 9:01 AM


Except that individual mules are colonies of individual cells and microorganisms that go through the process of evolution. Skin cells reproduce skin cells with modifications, same with other organs, same with gut bacteria. This doesn't mean that the body transforms into a new species (and evolution in a breeding population is not about necessarily becoming a new species), it means that heritable traits are passed from one generation of cells to the next, and that process maintains the ability of the mule to live.

Enjoy


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
to share.


• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

This message is a reply to:
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Replies to this message:
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