Login

Join for Free!
118827 members


What is the exact definition of life?

Debate and discussion of any biological questions not pertaining to a particular topic.

Moderator: BioTeam

What is the exact definition of life?

Postby Alberts » Thu Jan 22, 2009 9:27 am

I have been learning biology about 15 years. But I cannot gain the exact answer to the question all along__ What is life?
Although this question is seemingly so easy, but in fact there is not an unified theory about it in scientific world. Can you answer to this question in clear words?
What is life?
Alberts
Garter
Garter
 
Posts: 16
Joined: Thu Jan 08, 2009 3:39 pm

Postby mith » Thu Jan 22, 2009 8:26 pm

there isn't one.
Living one day at a time;
Enjoying one moment at a time;
Accepting hardships as the pathway to peace;
~Niebuhr
User avatar
mith
Inland Taipan
Inland Taipan
 
Posts: 5345
Joined: Thu Jan 20, 2005 8:14 pm
Location: Nashville, TN

Re: What is the exact definition of life?

Postby charles brough » Thu Jan 29, 2009 1:24 pm

Alberts wrote:I have been learning biology about 15 years. But I cannot gain the exact answer to the question all along__ What is life?
Although this question is seemingly so easy, but in fact there is not an unified theory about it in scientific world. Can you answer to this question in clear words?
What is life?

I deal with this in my book, "Destiny & Civilization." As you indicate, there is a big problem in defining it because there is no clear demarcation between "living" and non-life. I find it in my work when I define what a "society" is and find it can be defined in a way that a life cycle can be detected, that it undergoes natural selection and that it reproduces according to processes that are similar to but not identical to biological processes.

Perhaps, "life' is anything that does have a life cycle, reproduces and is subject to natural selection.

charles
http://atheisticp-science.com
Brough,
civilization-overview (dot) com
User avatar
charles brough
Coral
Coral
 
Posts: 155
Joined: Mon Jun 06, 2005 3:22 pm
Location: California


Postby favorina » Fri Jan 30, 2009 8:53 pm

Simple words for a difficult question...
"the capacity for evolution is sometimes taken as the only essential property of life; this definition notably includes viruses, which do not qualify under narrower definitions as they are acellular and do not metabolize"
Best i found. In the question of 'What is life?" there can never be a perfect ans.
favorina
Garter
Garter
 
Posts: 5
Joined: Fri Jan 30, 2009 6:07 pm

Postby JorgeLobo » Sat Jan 31, 2009 3:15 pm

There is no definition of "life" per se - evolutionary potential not withstanding. Part of the challenge is the context - cell vs. species. This is not a question scientists typically debate. It's like the old saw re. pornography - we know it when we see it.

Have to laugh at charles' shameless/egotistical plug for his book. The question was offered in a biological context and he "deals with it" in a nonscientific text and apparently offers no answer.
JorgeLobo
Coral
Coral
 
Posts: 424
Joined: Mon Nov 17, 2008 12:12 am

Re:

Postby charles brough » Sat Jan 31, 2009 7:54 pm

JorgeLobo wrote:There is no definition of "life" per se - evolutionary potential not withstanding. Part of the challenge is the context - cell vs. species. This is not a question scientists typically debate. It's like the old saw re. pornography - we know it when we see it.

Have to laugh at charles' shameless/egotistical plug for his book. The question was offered in a biological context and he "deals with it" in a nonscientific text and apparently offers no answer.


"shameless, egotistical"??? LOL :lol: Why do you get upset? It is "general discussion" and that is what we are talking about. Are you claiming that "life" can be defined only by cellular biology on Earth? That there can be no other form of "life" in the universe? How could you know that?

In one post, it was stated that the term can never be defined perfectly. I would say that holds true of every word and everything. Nothing is perfect. But do you really claim that it is only "we know it when we see it?" To make the term "life" more accurately defined, we should not give up but open up and consider what processes it has to have. What do you think they are?

a life cycle, reproduce, natural selection?
Brough,
civilization-overview (dot) com
User avatar
charles brough
Coral
Coral
 
Posts: 155
Joined: Mon Jun 06, 2005 3:22 pm
Location: California

Re: What is the exact definition of life?

Postby JorgeLobo » Sat Jan 31, 2009 9:01 pm

lol - the guilty dog barks. Not upset - just pointed it out - sorry if your feelings were hurt.

You may not have noticed it but this is a biology forum - the context in which the discussion was offered. You noted that you had nothing to offer (tho you had written a book!). From how many disciplines would you like to say you've no answer?
JorgeLobo
Coral
Coral
 
Posts: 424
Joined: Mon Nov 17, 2008 12:12 am

Re: What is the exact definition of life?

Postby Alberts » Thu Feb 05, 2009 8:58 am

I formerly had thought that: life=reproduction.
But some living entities ,e.g. mules, worker bees cannot reproduce. Some nonliving things, e.g. flames, salt crystals can reproduce.Later I noticed that all living things on Earth possess protein and/or nucleic acids. So I had drawn the definition in my view:
life=(protiens+nucleic acids)/proteins/nucleic acids.
But there is a probability that extraterrestrial lives may not based on proteins and nucleic acids. Maybe they based on plastic and rubber. Do you think so?
Alberts
Garter
Garter
 
Posts: 16
Joined: Thu Jan 08, 2009 3:39 pm

Re: What is the exact definition of life?

Postby JorgeLobo » Thu Feb 05, 2009 11:47 am

Don't think we can assume there is extraterrestial life. But - if it exists- why would it be based on another elemental system. Come on - plastics and rubber? Why do you think that?
JorgeLobo
Coral
Coral
 
Posts: 424
Joined: Mon Nov 17, 2008 12:12 am

Postby alextemplet » Thu Feb 05, 2009 7:03 pm

Plastic and rubber are mostly synthesized from organic compounds, so I doubt if anything not using similar biochemistry to terrestrial life would be able to come up with something like that. However, silicon has many similar properties to carbon, as is H2S similiar to H2O, so it is possible for life to exist that is not based on the chemistry we use.
Generally speaking, the more people talk about "being saved," the further away they actually are from true salvation.

~Alex
#2 Total Post Count
User avatar
alextemplet
King Cobra
King Cobra
 
Posts: 5599
Joined: Fri Dec 23, 2005 4:50 pm
Location: South Louisiana (aka Cajun Country)

Re: What is the exact definition of life?

Postby Alberts » Fri Feb 06, 2009 6:12 am

I have seen an interesting imagination from an magazine: There may exist a living form so small that they just live on the surface of electron; also there may exist a very large living form that our Galaxy just is an atom of their organism. Considering these, defining life become more and more difficult. Our Sun and other fixed stars, maybe just photons for other living organisms in universe. The proton, maybe just a very large galaxy for other very small living forms. Then how can we define life when we discovered them?
Alberts
Garter
Garter
 
Posts: 16
Joined: Thu Jan 08, 2009 3:39 pm

Re: What is the exact definition of life?

Postby JorgeLobo » Fri Feb 06, 2009 11:56 am

That's about as silly as anything I've seen here. Life so small it exists on electrons. Tell us - what are the data for that? Was the "magazine" a comic book?
JorgeLobo
Coral
Coral
 
Posts: 424
Joined: Mon Nov 17, 2008 12:12 am

Next

Return to General Discussion

Who is online

Users browsing this forum: No registered users and 8 guests