Things that don't move shouldn't be considered alive

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scratch123
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Things that don't move shouldn't be considered alive

Postby scratch123 » Thu Apr 28, 2011 12:05 am UTC

Instead of doing a simple check to see if something is alive by seeing if it can move on its own, for some reason life is defined by more abstract properties of the thing such as its ability to grow and reproduce. These properties of life aren't as easily observable as motion. Since people probably won't want to change the definition of life there should just be one word that describes all life with the ability to move on its own.

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Re: Things that don't move shouldn't be considered alive

Postby Sizik » Thu Apr 28, 2011 12:18 am UTC

Trees can't move on their own. Are they alive?
Roombas can move on their own. Are they alive?
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Re: Things that don't move shouldn't be considered alive

Postby TaintedDeity » Thu Apr 28, 2011 12:42 am UTC

When I was taught what was living and what was not I was taught that something had to move to be alive. This may have been lies.

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Re: Things that don't move shouldn't be considered alive

Postby Qaanol » Thu Apr 28, 2011 12:55 am UTC

scratch123 wrote:there should just be one word that describes all life with the ability to move on its own.

That would be “animal”. As in “animated”.
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Re: Things that don't move shouldn't be considered alive

Postby ++$_ » Thu Apr 28, 2011 2:36 am UTC

Historically, people have considered plants to be nonliving because they don't move. And by "historically," I mean "I know someone who holds this belief because her religion told her it was true, and the idea got into her religion because the founders of the religion held it umpteen years ago." I don't think this is a good idea, because plants are alive for all practical purposes and they would still be alive without phototaxis.

The problem with describing life as anything that moves on its own is that all kinds of things, from oxygen molecules to robots to hurricanes to tectonic plates, move on their own. You have to get into what "on its own" means, and it is pretty tricky to exclude hurricanes and not bacteria when it comes right down to it.

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Re: Things that don't move shouldn't be considered alive

Postby Shivahn » Thu Apr 28, 2011 2:51 am UTC

Biology is a fuzzy science. Attempts to pin all things into specific discrete categories is doomed to failure. The world is far weirder than most people think.

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Re: Things that don't move shouldn't be considered alive

Postby Dopefish » Thu Apr 28, 2011 4:57 pm UTC

I prefer to get my definitions of what it means for something to be 'alive' by talking to preschoolers*. 'is X alive' 'yes silly!' 'why?' '<whatever>' 'Oh, then Y is alive too then?' 'Nooo, of course not' etc.

I actually have more interesting conversations there than with older people who quickly just conclude that defining 'alive' is a stupid waste of time.

*= Preferably ones that happen to be cousins or you otherwise have a non-creepy reason to talk to.

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Re: Things that don't move shouldn't be considered alive

Postby Gigano » Thu Apr 28, 2011 5:44 pm UTC

A a biologist I consider anything to be alive if it can:

i) display growth and reproduce itself independently;
ii) display metabolism;
iii) display homoeostasis;
iv) display evolution.

This definition would include all prokaryotes such as bacteria, and eukaryotes such as protozoa, plants, fungi, animals etc.

A virus for example is not considered alive by this definition, as a virus cannot reproduce itself independently. It requires the molecular machinery of a true cell in order to do so.

However, as said before, definitions are artificial and there is no distinct line between what is and is not truly alive.
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Re: Things that don't move shouldn't be considered alive

Postby Velifer » Thu Apr 28, 2011 6:03 pm UTC

scratch123 wrote:one word that describes all life with the ability to move on its own.

Nekton. It's actually quite a useful term in some sciences.
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Re: Things that don't move shouldn't be considered alive

Postby Moose Hole » Thu Apr 28, 2011 6:07 pm UTC

Gigano wrote:i) display growth and reproduce itself independently;
Does that mean bananas (the kind spliced on to other trees or whatever) are not alive? What about sterile animals like donkeys or whatever?

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Re: Things that don't move shouldn't be considered alive

Postby Izawwlgood » Thu Apr 28, 2011 6:18 pm UTC

You guys, it's a troll.

I rarely move, and I'm pretty alive. Hell, I haven't moved in over two hours!
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Re: Things that don't move shouldn't be considered alive

Postby Malarowski » Thu Apr 28, 2011 6:32 pm UTC

Moose Hole wrote:
Gigano wrote:i) display growth and reproduce itself independently;
Does that mean bananas (the kind spliced on to other trees or whatever) are not alive? What about sterile animals like donkeys or whatever?


Bananas are the fruits/seeds of the banana tree, which does display growth. As far as mules (and ligers etc) go, they can reproduce, but their offspring is not viable, which is why they are not a species, but still alive. Not every single one of them is 'sterile'.

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Re: Things that don't move shouldn't be considered alive

Postby Technical Ben » Thu Apr 28, 2011 6:58 pm UTC

Gigano wrote:A a biologist I consider anything to be alive if it can:

i) display growth and reproduce itself independently;
ii) display metabolism;
iii) display homoeostasis;
iv) display evolution.

This definition would include all prokaryotes such as bacteria, and eukaryotes such as protozoa, plants, fungi, animals etc.

A virus for example is not considered alive by this definition, as a virus cannot reproduce itself independently. It requires the molecular machinery of a true cell in order to do so.

However, as said before, definitions are artificial and there is no distinct line between what is and is not truly alive.


Yep. A by-product of all those things is "movement". Even if we count it on the atomic scale. ;)
[edit]
Oh, and on the part to do with "can reproduce". People being picky about ligers and such, miss one tiny point. An animal is made up of cells. These do reproduce. So the whole animal is alive.
Also, I don't think it "has" to display evolution to be alive. If something was in genetic stasis, for whatever reason, it could still be considered "alive". IE a clone. ;)
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Re: Things that don't move shouldn't be considered alive

Postby TheChewanater » Fri Apr 29, 2011 2:20 am UTC

Moose Hole wrote:
Gigano wrote:i) display growth and reproduce itself independently;
Does that mean bananas (the kind spliced on to other trees or whatever) are not alive? What about sterile animals like donkeys or whatever?

I can't reproduce independently. Am I not alive?
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Re: Things that don't move shouldn't be considered alive

Postby Soralin » Fri Apr 29, 2011 2:31 am UTC

Technical Ben wrote:Yep. A by-product of all those things is "movement". Even if we count it on the atomic scale. ;)

If we include movement on the atomic scale, that includes everything which is not at a temperature of absolute zero. :)

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Re: Things that don't move shouldn't be considered alive

Postby Technical Ben » Fri Apr 29, 2011 11:43 am UTC

I said that is was an inclusive requirement. But also how silly saying something that does not move is not alive. True, but then, can it even exist if we have no way of detecting it, or if it's "frozen" in time?
Hence why we have more than one for life. other than it "being alive" that is. ;)
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Re: Things that don't move shouldn't be considered alive

Postby Interactive Civilian » Fri Apr 29, 2011 1:37 pm UTC

Gigano wrote:A a biologist I consider anything to be alive if it can:
~snip~
However, as said before, definitions are artificial and there is no distinct line between what is and is not truly alive.

Indeed. As an example of that flexibility, you almost need to make an artificial distinction between viruses and, say, dormant bacterial spores, in the following sense: Both have to be in the right conditions to engage the active part of their life cycles. If a bacterial spore is not in the right environment conducive to switching all of its molecular machinery on, then it will be dormant for ever. If a virus is not in the right conditions to turn on its molecular machinery (activating the proteins to start hijacking a cell's machinery, thus entering the "active" part of its "life cycle"), it will also be forever dormant.

As a biologist (well, formerly; now a biology teacher), I've come to both broaden my definition of "life" and accepted the fact that it's an arbitrary definition, rather than an innate quality, especially and most obviously at those levels. Granted, there is the issue of all of the emergent properties of life as complexity increases, but overall, and overly simplistically, life is "simply" a bunch of complexly interacting, self-organizing chemical reactions, all done for the "benefit" of propagating replicators (genes in the case of life as we know it on Earth).

I tend to draw the line on just the other side of viruses, virions, and viroids, because they exhibit true molecular heredity, and that is certainly one of the key characteristics in the biological definition of "life". Prions, for example, while biologically very interesting, do not, because the only thing inherited is shape, rather than molecular "signature". I'm a big fan of the replicator/vehicle point of view (which is not mutually exclusive from the whole organism point of view; it's merely the "other face of the Necker cube" as Dawkins puts it) for talking about biological life. This, then, includes viruses, because they are true replicators which have either 1.) foregone vehicles of their own or 2.) expanded their range of possible vehicles, depending on how you want to look at it (again, not mutually exclusive).

But, I'm rambling... :)

In my opinion, viruses and such can usefully be considered "molecular organisms", because while they are dormant for a significant part of their life-cycles, when they do find a "vehicle" to work in, they exhibit the molecular organization that we think of when talking about the usual definitions of "life". From the "gene's-eye-view", it doesn't matter whether or not that particular replicator created the vehicle or subverted it.

But, again, at that level, the definition becomes very arbitrary. :)

[EDIT]
Wanted to address this:
Technical Ben wrote:Also, I don't think it "has" to display evolution to be alive. If something was in genetic stasis, for whatever reason, it could still be considered "alive". IE a clone. ;)


Evolution isn't an a priori definer of life. It is an emergent property from inheritance and imperfect replication, both of which are characteristics of living things. In a hypothetical Hardy-Weinberg Equilibrium situation (which is most simply defined as a population which is not evolving), yes you could consider the organisms of that population alive. We are not in disagreement there. However, that is an impossible situation, due to the fact that replication is imperfect. Interestingly (to me, anyway), if such a population were to appear (say, one which evolved perfect error correction in its replication machinery), it would probably go extinct, as changing conditions would give advantage to imperfect replicators capable of introducing variation. Despite the fact that replicators "want" to be perfect (i.e. the population tends to become filled with replicators that are best at making copies of themselves), it is "lucky" for us that replication is imperfect. If that were not the case, evolution would have never happened (as I'm sure you know and/or understand :) ).

As an aside: For any biologists who haven't yet read it and for any would-be biologists out there, "The Selfish Gene" by Richard Dawkins is a must read if you really want a good understanding of so many of the hows and whys of evolution. It's written at a level that anyone with a high school level of biology education can understand, but it is very insightful, and it will give you a better frame of reference for understanding what biologists (especially straight up "evolutionary biologists") are really studying.

[late edit 2] minor typos; probably missed a few, but oh well ^^;;
Last edited by Interactive Civilian on Fri Apr 29, 2011 2:17 pm UTC, edited 2 times in total.
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Re: Things that don't move shouldn't be considered alive

Postby AvatarIII » Fri Apr 29, 2011 1:52 pm UTC

i remeber being taught a mnemonic at school about what makes something alive,
just looked it up, it was MRS GREN (Movement; Respiration: Sensitivity; Growth; Reproduction; Excretion; Nutrition)
http://www.sambal.co.uk/mrsgren.html

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Re: Things that don't move shouldn't be considered alive

Postby Interactive Civilian » Fri Apr 29, 2011 2:02 pm UTC

AvatarIII wrote:i remeber being taught a mnemonic at school about what makes something alive,
just looked it up, it was MRS GREN (Movement; Respiration: Sensitivity; Growth; Reproduction; Excretion; Nutrition)
http://www.sambal.co.uk/mrsgren.html

That mnemonic will include most of what we consider life, so for a starting point, it's not a bad thing to learn. However, as mentioned above, the actual situation is more complex than that. As long as you are willing to use that definition as a starting point, rather than using it to be exclusionary, you can be well on your way to understanding "real" biology. :)

[edit] (using the general "you", not you specifically, AvatarIII. I have no idea how deep your understanding of biology is and am making no statements about it :) )
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Re: Things that don't move shouldn't be considered alive

Postby AvatarIII » Fri Apr 29, 2011 2:07 pm UTC

Interactive Civilian wrote:
AvatarIII wrote:i remeber being taught a mnemonic at school about what makes something alive,
just looked it up, it was MRS GREN (Movement; Respiration: Sensitivity; Growth; Reproduction; Excretion; Nutrition)
http://www.sambal.co.uk/mrsgren.html

That mnemonic will include most of what we consider life, so for a starting point, it's not a bad thing to learn. However, as mentioned above, the actual situation is more complex than that. As long as you are willing to use that definition as a starting point, rather than using it to be exclusionary, you can be well on your way to understanding "real" biology. :)

[edit] (using the general "you", not you specifically, AvatarIII. I have no idea how deep your understanding of biology is and am making no statements about it :) )


lol, thanks for making that clear, i think i learned that mnemonic when i was about 10, or maybe younger and continued to study biology until i was 18, so yeah i accumulated quite a bit more knowledge on the subject :D i was just posting that because this thread reminded me of it, and i thought it would be interesting to post the kind of starting point for the definition of life that is taught in schools

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Re: Things that don't move shouldn't be considered alive

Postby qetzal » Fri Apr 29, 2011 4:15 pm UTC

I'm a career molecular biologist, and I just want to voice my agreement with almost everything Interactive Civilian said above. Especially this:

Interactive Civilian wrote:As a biologist (well, formerly; now a biology teacher), I've come to both broaden my definition of "life" and accepted the fact that it's an arbitrary definition, rather than an innate quality, especially and most obviously at those levels. Granted, there is the issue of all of the emergent properties of life as complexity increases, but overall, and overly simplistically, life is "simply" a bunch of complexly interacting, self-organizing chemical reactions, all done for the "benefit" of propagating replicators (genes in the case of life as we know it on Earth).


The only thing I'd change is the bit about life being for the "benefit" of propagating replicators. I know it's just a metaphor, but I still think it's flawed and misleading. Life exists and persists as systems of chemical reactions simply because those systems are self-replicating. The systems themselves "benefit" rather than any particular component of the systems.

Dawkins' concept of the selfish gene certainly helped shape my views on this. It disputed the traditional focus on whole organisms as the fundamental unit of life, espousing individual genes as the fundamental units instead. That caused me to rethink these questions, but my ultimate conclusion was that genes are no more fundamental than any other element of the system. Dawkins famously said that an organism is just a gene's way of making more genes, but we could as easily say that a gene is just a protein's way of making more proteins, or that a protein is just a lipid's way of making more lipids. In reality, life is just a bunch of self-sustaining, interactive systems that manage to generate imperfect copies of themselves faster than they dissipate. No single component (or class or grouping thereof) is really the "point" or "beneficiary" of the whole process.

FWIW, I too include viruses as part of life, even as I agree with IA that the distinction between life and non-life is arbitrary.

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Re: Things that don't move shouldn't be considered alive

Postby ClemsonCarter » Sun May 01, 2011 1:43 am UTC

you're moving in some direction at a given speed. i'm moving in the same direction at the same speed. you are not moving with respect to my frame of reference, can i say that you are not living??

seriously though, i've always had an issue with the part of viruses not being considered "alive" because they can't reproduce without a host. i've always just kind of considered them as the "ultimate" parasite in a ways, or the cellular parasite if you will.
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Re: Things that don't move shouldn't be considered alive

Postby Technical Ben » Sun May 01, 2011 8:29 am UTC

I think it's more that they are not considered "alive" outside of the mechanism or replication.
For example, your DNA outside of a cell, is not "alive". Or a protein is not "alive" on it's own. But all these things working together are considered alive.
The DNA needs other parts to replicate. On it's own, it's got the code for live, but is not alive. Just like a computer program code written on paper is not "running" until it's on a pc.
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Re: Things that don't move shouldn't be considered alive

Postby Gigano » Sun May 01, 2011 9:37 am UTC

Technical Ben wrote:I think it's more that they are not considered "alive" outside of the mechanism or replication.
For example, your DNA outside of a cell, is not "alive". Or a protein is not "alive" on it's own. But all these things working together are considered alive.
The DNA needs other parts to replicate. On it's own, it's got the code for live, but is not alive. Just like a computer program code written on paper is not "running" until it's on a pc.


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Re: Things that don't move shouldn't be considered alive

Postby Interactive Civilian » Sun May 01, 2011 4:14 pm UTC

qetzal wrote:That caused me to rethink these questions, but my ultimate conclusion was that genes are no more fundamental than any other element of the system. Dawkins famously said that an organism is just a gene's way of making more genes, but we could as easily say that a gene is just a protein's way of making more proteins, or that a protein is just a lipid's way of making more lipids..

Hmmm... I agree that "benefit" can be misleading or at least easily misunderstood. But, I think the genes do deserve their special, perhaps "privileged" place in the system. Yes, there is all kinds of feedback and interdependence, especially in modern living systems which have had their ~3.8 billion years to evolve, so it can be considered senseless to consider "benefits" for any one part over another. But, ultimately it is usually the genes to which everything else leads back to.

The reason I agree with the metaphor is because it is a useful way of thinking, especially about evolution and trying to understand how and why things evolve. With the caveat that it is important to always keep in mind that it is a metaphor rather than a descriptor. I believe this was Dawkins's intent when using the metaphor.

While saying "a gene is just a lipid's way of making more enzymes to make more lipids" is just as accurate, how much use is such a way of thinking? Granted it may be a failure of my own imagination, but I can't particularly think of any uses. However, when talking about expression of genes and the resulting phenotypes, using metaphors such as "for the benefit of the genes" or "it's the gene's way of leveraging itself into future generations" and such can be useful in helping to organize thinking about evolution (again, so long as one keeps it firmly in mind that it's a metaphor, and it's always a good idea to "back-translate" the metaphor into what is really happening), as Dawkins so brilliantly and eloquently explained in both "The Selfish Gene" and "The Extended Phenotype".

All said, you do make very good points, and are probably far more knowledgeable than I am about this. Perhaps rephrasing "all done for the 'benefit' of propagating replicators" to "all done for the 'benefit' (if one chooses to think in such terms) of propagating the self-organizing, self-replicating living system" would work?

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Re: Things that don't move shouldn't be considered alive

Postby scratch123 » Sun May 01, 2011 7:44 pm UTC

http://en.wikipedia.org/wiki/Motile

So I decided to check out wikipedia and apparently there is a word for this. I guess I should have done more research before making this topic. I wonder why I never heard this word before now.

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Re: Things that don't move shouldn't be considered alive

Postby idobox » Sun May 01, 2011 11:16 pm UTC

I think we all agree that virus are a part of the "realm of life", like a spore, a seed, or even dead things like hair or a horn are.
Wether they can be considered alive or organisms is more difficult. It all depends on your definition of the words. Biology is blurry, and virus are definitely near the edge.
I like to consider virus as pieces of genetic code rather than organisms. They can be harmful (most often) or beneficial to the cell, mutate, propagate, are subject to natural selection, can be integrated to a species genome. The only difference is the way they propagate, through virions rather than mitose and meiose only. In that sense, they are not less alive than a gene, or a chromosome, and virions are just a vessel, like gametes.
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Re: Things that don't move shouldn't be considered alive

Postby qetzal » Mon May 02, 2011 7:04 pm UTC

@Interactive Civilian,

I don't think I'm especially knowledgeable in this area. I'm a molecular biologist, but I don't really do any work directly related to evolution. So please don't look at my thoughts as anything more than that.

I agree that there's value in Dawkins' metaphor. I just worry that it's potentially misleading (to ourselves and to others) to suggest that any single class of molecules is somehow the most fundamental.

That said, genes do have a critical property that all other biomolecules lack. DNA and some RNAs are the only biomolecules where a chemical modification (i.e. a mutation) can be heritably passed on to an organism's progeny. Proteins, lipids, carbohydrates, and other biomolecules can all undergo chemical modification, and those modificatios can alter an organism's phenotype, but they can't be heritably passed on to the next generation. (Perhaps there are a few cases where certain very specific non-nucleic acid modifications might be passed on epigenetically, but I wouldn't consider that equivalent.)

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Re: Things that don't move shouldn't be considered alive

Postby thorgold » Thu May 05, 2011 4:40 am UTC

idobox wrote:I think we all agree that virus are a part of the "realm of life", like a spore, a seed, or even dead things like hair or a horn are.
Wether they can be considered alive or organisms is more difficult. It all depends on your definition of the words. Biology is blurry, and virus are definitely near the edge.
I like to consider virus as pieces of genetic code rather than organisms. They can be harmful (most often) or beneficial to the cell, mutate, propagate, are subject to natural selection, can be integrated to a species genome. The only difference is the way they propagate, through virions rather than mitose and meiose only. In that sense, they are not less alive than a gene, or a chromosome, and virions are just a vessel, like gametes.

I disagree with the fact that viruses are alive. Of the three requirements for life:

1) Reproduction
2) Movement on some level
3) Homeostasis and metabolism

They only marginally fulfill the first requirement (and even then through external means). Viruses, from a technical standpoint, are just extremely complex chemical structures - a protein husk around a few strands of RNA. The virus itself is incapable of motion, and accordingly it is incapable of reacting to its environment or engaging in metabolic process. It's like an extremely complex poison (as its Latin namesake implies).

However, their complexity does raise the question of their being alive, and how the HELL they fit into evolutionary theory.
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Re: Things that don't move shouldn't be considered alive

Postby Gigano » Thu May 05, 2011 7:57 am UTC

thorgold wrote:Viruses, from a technical standpoint, are just extremely complex chemical structures - a protein husk around a few strands of RNA.


Although I agree with your point on viruses not being considered alive, they are not just a protein husk with RNA, they can be more than that. Both HIV and the influenza virus have a lipid membrane much like prokaryotes and eukaryotes have. Also, not all viruses have RNA as their genetic carrier. Some, like the Varicella Zoster virus (the virus which causes chicken pocks and is a member of the herpesviridae family) and the smallpox virus (a member of the poxyviridae familiy) have DNA inside of them. And apart from classifying viruses based on them either having or not having a membrane, having either DNA or RNA as their genetic carrier, they are also classified in terms of them having either double stranded or single stranded DNA or RNA.

thorgold wrote:The virus itself is incapable of motion, and accordingly it is incapable of reacting to its environment or engaging in metabolic process. It's like an extremely complex poison (as its Latin namesake implies).


Viruses are perfectly capable of motion in the same way a lot of bacteria are: they simple rely on environmental currents (via droplets in the air or liquids) for transportation. Much like bacteria they also have adhesive proteins (haemagglutinins) which allow them to attach themselves to cells at will. Active transportation as we experience it or like a bacteria with flagella is indeed not a property of viruses.

thorgold wrote:However, their complexity does raise the question of their being alive, and how the HELL they fit into evolutionary theory.


There are multiple hypotheses on the origins of viruses. They have most likely been around ever since life first began. Check out the Wikipedia article on viruses (Origins section) or apply any general Google search and you'll find out loads about the evolution of viruses.
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Re: Things that don't move shouldn't be considered alive

Postby Interactive Civilian » Thu May 05, 2011 10:52 am UTC

thorgold wrote:However, their complexity does raise the question of their being alive, and how the HELL they fit into evolutionary theory.

As imperfect replicators made of the same genetic material used for heredity in all known life on Earth, they fit just fine. Theories of Evolution have no problems with viruses. Genetic analyses show gene flow between viruses and various host organisms, and there is evidence that a good amount of our own genome comes from viral "hitchhikers".

What problems do you think theories of evolution would have with viruses?
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Re: Things that don't move shouldn't be considered alive

Postby BlackSails » Thu May 05, 2011 12:51 pm UTC

If viruses fail being alive because they cant independently reproduce, then there are several species of bacteria that we also need to rule as "not alive", because they cannot independently reproduce.

(Also, I cannot independently reproduce)

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Re: Things that don't move shouldn't be considered alive

Postby Gigano » Thu May 05, 2011 1:12 pm UTC

BlackSails wrote:If viruses fail being alive because they cant independently reproduce, then there are several species of bacteria that we also need to rule as "not alive", because they cannot independently reproduce.

(Also, I cannot independently reproduce)


As has been addressed the definition should only be applied to single cells, not necessarily the organism in its entirety. Your somatic cells can reproduce (multiply) independently; this is not so for an individual virus.
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Re: Things that don't move shouldn't be considered alive

Postby gmalivuk » Thu May 05, 2011 2:20 pm UTC

thorgold wrote:Viruses, from a technical standpoint, are just extremely complex chemical structures
So's your mom.
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Re: Things that don't move shouldn't be considered alive

Postby Technical Ben » Thu May 05, 2011 2:28 pm UTC

Could you model a car as an extremely complex chemical structure? :?:
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Re: Things that don't move shouldn't be considered alive

Postby gmalivuk » Thu May 05, 2011 3:10 pm UTC

Is your mom a car?
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Re: Things that don't move shouldn't be considered alive

Postby BlackSails » Thu May 05, 2011 3:46 pm UTC

Gigano wrote:
BlackSails wrote:If viruses fail being alive because they cant independently reproduce, then there are several species of bacteria that we also need to rule as "not alive", because they cannot independently reproduce.

(Also, I cannot independently reproduce)


As has been addressed the definition should only be applied to single cells, not necessarily the organism in its entirety. Your somatic cells can reproduce (multiply) independently; this is not so for an individual virus.


There is still my first point, that there are bacteria that are obligate intracellular parasites.

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Re: Things that don't move shouldn't be considered alive

Postby Izawwlgood » Thu May 05, 2011 4:18 pm UTC

There are multicellular organisms that are obligate parasites as well.
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Re: Things that don't move shouldn't be considered alive

Postby Velifer » Thu May 05, 2011 4:41 pm UTC

gmalivuk wrote:Is your mom a car?

How did you know?
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Re: Things that don't move shouldn't be considered alive

Postby gmalivuk » Thu May 05, 2011 4:55 pm UTC

Too many people have ridden her for her to be anything else.
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