Life vs. Non-Life

[PhilosophicalBluster]

Now, it seems to me that there is a bit of trouble for some on this board trying to classify what is and is not life.

Conventional

The consensus is that life is a characteristic of organisms that exhibit all or most of the following phenomena:[9][10]

1. Homeostasis: Regulation of the internal environment to maintain a constant state; for example, electrolyte concentration or sweating to reduce temperature.
2. Organization: Being structurally composed of one or more cells, which are the basic units of life.
3. Metabolism: Consumption of energy by converting chemicals and energy into cellular components (anabolism) and decomposing organic matter (catabolism). Living things require energy to maintain internal organization (homeostasis) and to produce the other phenomena associated with life.
4. Growth: Maintenance of a higher rate of synthesis than catabolism. A growing organism increases in size in all of its parts, rather than simply accumulating matter. The particular species begins to multiply and expand as the evolution continues to flourish.
5. Adaptation: The ability to change over a period of time in response to the environment. This ability is fundamental to the process of evolution and is determined by the organism's heredity as well as the composition of metabolized substances, and external factors present.
6. Response to stimuli: A response can take many forms, from the contraction of a unicellular organism to external chemicals, to complex reactions involving all the senses of higher animals. A response is often expressed by motion, for example, the leaves of a plant turning toward the sun (phototropism) and chemotaxis.
7. Reproduction: The ability to produce new organisms. Reproduction can be the division of one cell to form two new cells. Usually the term is applied to the production of a new individual (either asexually, from a single parent organism, or sexually, from at least two differing parent organisms), although strictly speaking it also describes the production of new cells in the process of growth.

(Links removed)
(Source: Life - Wikipedia, the free encyclopedia)

It's hard to believe that I actually have to do this, but let's see if plants check out with this definition:

1. Homeostasis: Plants retain homeostasis through a number of processes, such as transpiration, pressure flow mechanism, root pressure mechanism, and other macrocellular ways that plants have to make sure its parts maintain relatively consistent concentration of ions, H2O, and other vital nutrients. This constitutes homeostasis.

2. Organization: Plants are composed of many cells. This constitutes organization.

3. Metabolism: Plants use photosynthesis to create glucose, and then turn that glucose into ATP via respiration. This constitutes metabolism.

4. Growth: Plants have meristematic tissue that can grow vertically or laterally via mitosis of various cambium layers. This constitutes growth.

5. Adaptation: Plants over time have evolved from bryophytes to pteridophytes to gymnosperms to angiosperms. As angiosperms can reproduce more efficiantly, producing more genetic diversity in a smaller amount of time via non-flagellated sperm and a faster growing pollen tube than gymnosperms, they have adapted to their environment and are flourishing because of that fact. This constitutes adaptation.

6. Response to Stimuli: Plants have developed phototropism (response to light), thigmotropism (response to touch), and photoperiodism (response to the length of day and night). This constitutes response to stimuli.

7. Reproduction: All types of plants reproduce. Bryophytes and pteridophytes reproduce via flagellated sperm and antheridia, and gymnosperms and angiosperms reproduce via pollination. This constitutes reproduction.

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Plants meet all the requirements of life. (And in writing that I was able to study for my bio exam )

 

[Gawron]

I agree.....

 

[Matthewj1985]

I just finished up "The Hot Zone" and they call viruses "life-forms" because they have attributes of "life" and attributes of "non-life". It really sparked my curiosity and I have been reading more into the evolution of the virus, super interesting stuff.

 

[Cabal]

Was having a discussion about prions recently. I take it they don't fit the criteria?

 

[ragarth]

Was having a discussion about prions recently. I take it they don't fit the criteria?

For the same reason that I don't consider viri to be alive per-se, prions are not either- they don't fit the definition of life since they don't reproduce on their own or have metabolisms.

 

[ragarth]

Now, it seems to me that there is a bit of trouble for some on this board trying to classify what is and is not life.
[/list]
(Links removed)
(Source: Life - Wikipedia, the free encyclopedia)

It's hard to believe that I actually have to do this, but let's see if plants check out with this definition:

1. Homeostasis: Plants retain homeostasis through a number of processes, such as transpiration, pressure flow mechanism, root pressure mechanism, and other macrocellular ways that plants have to make sure its parts maintain relatively consistent concentration of ions, H2O, and other vital nutrients. This constitutes homeostasis.

2. Organization: Plants are composed of many cells. This constitutes organization.

3. Metabolism: Plants use photosynthesis to create glucose, and then turn that glucose into ATP via respiration. This constitutes metabolism.

4. Growth: Plants have meristematic tissue that can grow vertically or laterally via mitosis of various cambium layers. This constitutes growth.

5. Adaptation: Plants over time have evolved from bryophytes to pteridophytes to gymnosperms to angiosperms. As angiosperms can reproduce more efficiantly, producing more genetic diversity in a smaller amount of time via non-flagellated sperm and a faster growing pollen tube than gymnosperms, they have adapted to their environment and are flourishing because of that fact. This constitutes adaptation.

6. Response to Stimuli: Plants have developed phototropism (response to light), thigmotropism (response to touch), and photoperiodism (response to the length of day and night). This constitutes response to stimuli.

7. Reproduction: All types of plants reproduce. Bryophytes and pteridophytes reproduce via flagellated sperm and antheridia, and gymnosperms and angiosperms reproduce via pollination. This constitutes reproduction.

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Plants meet all the requirements of life. (And in writing that I was able to study for my bio exam )

I provided this same definition of life to the fellow who prompted you to make this post, unfortunately it was summarily ignored in deference to arbitrary, meaningless statements such as 'metabolism requires the elimination of waste through an orifice' and 'life requires an internal circulation system'. I can't help but make the link between these and arguments such as 'lightning is caused by zeus' and 'mice spontaneously grow from putting sacks over hay' in their absolute level of arbitrariness.

 

[lostaquarium]

Was having a discussion about prions recently. I take it they don't fit the criteria?

I'm not sure if viruses are life-forms, but prions definitely are not. In my opinion Prions don't even reproduce, they just change the conformation of surrounding proteins.

 

[Taure]

The definition of life is somewhat irrelevant to most of the discussions that take place here.

Most often discussions where this may be brought up would be discussions about abortion and similar issues.

In which case the technical definition of life is a bit pointless. As you say, plants are alive, so are dogs, etc.

More important than what counts as alive, IMO, is at what point do we count something as a person - i.e. that which we view as possessing certain rights e.g. the right to life.

 

[ragarth]

The definition of life is somewhat irrelevant to most of the discussions that take place here.

Most often discussions where this may be brought up would be discussions about abortion and similar issues.

In which case the technical definition of life is a bit pointless. As you say, plants are alive, so are dogs, etc.

More important than what counts as alive, IMO, is at what point do we count something as a person - i.e. that which we view as possessing certain rights e.g. the right to life.

This thread spawns from someone in my 'creationism and astrobiology' thread attempting to say it doesn't matter if we find plantlife on another planet, because plant life is not life, therefore it's not finding life beyond earth. The fellow still apparently holds to this belief, but is currently in the process of assessing the arguments he uses to back up his assertion that plants are not alive.

The 2nd part- when something should possess rights, is a moral delimma I'm currently grappling with.

 

[Toclafane]

This thread spawns from someone in my 'creationism and astrobiology' thread attempting to say it doesn't matter if we find plantlife on another planet, because plant life is not life, therefore it's not finding life beyond earth. The fellow still apparently holds to this belief, but is currently in the process of assessing the arguments he uses to back up his assertion that plants are not alive.

The 2nd part- when something should possess rights, is a moral delimma I'm currently grappling with.

Also it has to do with eating plants, killing them (death) in the process, showing Death before the fall.

 

[ragarth]

Also it has to do with eating plants, killing them (death) in the process, showing Death before the fall.

If the fall never occurred, then this probablem disappears.

 

[Gracchus]

The 2nd part- when something should possess rights, is a moral delimma I'm currently grappling with.

What is a right? Name one right that is universally recognized.

 

[ragarth]

What is a right? Name one right that is universally recognized.

That's an odd question, actually. A right is a liberty that is reserved for an individual or group. The fact that there isn't a universally recognized set of rights is why we must think about this issue. If there were a universally recognized set of rights then we would not need to put thought to the problem of codifying who should have what rights.

It's important to note that there not being a universal set of rights is not an argument that there should not be, because depending on the scope of how you define your society, there is probably a basic set of rights that will be best for the development of your society.

I just happen to have my scope of what defines my society a bit larger than others. This is an ethics and morals debate, however, if you want to continue this, I suggest moving to a thread on that forum.

 

[PhilosophicalBluster]

I just finished up "The Hot Zone" and they call viruses "life-forms" because they have attributes of "life" and attributes of "non-life". It really sparked my curiosity and I have been reading more into the evolution of the virus, super interesting stuff.

I read the first couple chapters of "The Hot Zone" when I was in like 6th grade. Scared the you-know-what out of me, but that's probably the reason I'm so interested in virology today.

 

[Toclafane]

Dear Philothei

is a fetus alive then? or a zygot??? why we kill them ?

Why ask this question in the Rep system, and not in in the open ?

EDIT: To Answer your Rep Question (Not really a good or honest way to ask a question though)

We don't kill them, you might (I don't know) but I do not, so I'm not part of your "We" that kills them.

Is a Fetus & Zygote alive ? Yes, just like a single nerve cell is alive.

 

[juvenissun]

I think most people simply have a closed mind as bad as that of creationist.

A biological system is a life. Fine. But why should it be the limit?

What is wrong if we say that anything that moves is a life? So automobile is alive sometimes or all the time before it goes to the junkyard. What is wrong with this wider definition?

Why do we have to restrict the action of life only to a biological one?

 

[Hespera]

I think most people simply have a closed mind as bad as that of creationist.

A biological system is a life. Fine. But why should it be the limit?

What is wrong if we say that anything that moves is a life? So automobile is alive sometimes or all the time before it goes to the junkyard. What is wrong with this wider definition?

Why do we have to restrict the action of life only to a biological one?

First off, because "a life" has a completely different meaning from "alive".
You should decide which one you mean, you mix the two as if they are the same.

If you want to define life in terms of motion, then every last thing atom and sub atomic particle in the universe is alive. Which makes the term meaningless.

That is one of the many reasons nobody is going to go along with your new definitions. Esp as you have not even learned the old ones, like the difference between "alive" and "a life".

 

[ragarth]

First off, because "a life" has a completely different meaning from "alive".
You should decide which one you mean, you mix the two as if they are the same.

If you want to define life in terms of motion, then every last thing atom and sub atomic particle in the universe is alive. Which makes the term meaningless.

That is one of the many reasons nobody is going to go along with your new definitions. Esp as you have not even learned the old ones, like the difference between "alive" and "a life".

There is actually a movement to expand the definition of 'life' to include systems beyond biological systems. The idea is that we don't know if our form of life here on our mudrock is the only way within which intelligence and autonomy can arise. That said, juv's definition is silly because a car has no autonomy, no reproductive capacity, no system of growth, evolution, reaction, etc. It relies upon an external entity for everything other than being an ambitious paperweight.

 

[juvenissun]

First off, because "a life" has a completely different meaning from "alive".
You should decide which one you mean, you mix the two as if they are the same.

If you want to define life in terms of motion, then every last thing atom and sub atomic particle in the universe is alive. Which makes the term meaningless.

That is one of the many reasons nobody is going to go along with your new definitions. Esp as you have not even learned the old ones, like the difference between "alive" and "a life".

Not really. When I see a rock sits still, I won't say it is alive, even I can understand that its atoms are shaking all the time. It depends on the scale of perception. On the same token, if you say a neuron is alive, are you saying the molecules of the neuron are also alive?

Also, what is wrong to think that everything is alive? Instead of losing its meaning, would it make everything more meaningful? Is that the basis of pantheism?

 

[juvenissun]

There is actually a movement to expand the definition of 'life' to include systems beyond biological systems. The idea is that we don't know if our form of life here on our mudrock is the only way within which intelligence and autonomy can arise. That said, juv's definition is silly because a car has no autonomy, no reproductive capacity, no system of growth, evolution, reaction, etc. It relies upon an external entity for everything other than being an ambitious paperweight.

Your thinking (criteria) is still confined to a biological system. If non-biological, then why reproduce? If not reproduce, is the earth alive?