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Life's two most fundamental properties are homeostasis and reproduction. The loss of these two combined with its parasitic nature makes this cell a form on non-

by tsoukase 11mo ago

Life's two most fundamental properties are homeostasis and reproduction. The loss of these two combined with its parasitic nature makes this cell a form on non-life.

anothernewdude 11mo ago
Lots of types of life give up on homeostasis along particular dimensions because the environment is doing it well enough. Viruses do reproduce. If you say "well not by themselves" neither do humans.
- tsoukase 11mo ago
  No life exists "by themselves". Self-replication means using only its own DNA and not mangling with other's. Virii are not only parasites but dead matter (a ribonucl molecule surrounded by proteins that happens to stick to other cells, like dirt on the skin). Gut microbioma is parasite. There is another life property that this object does not fulfill and is called Teleonomia, that is governed by an ultimate goal.
  - anothernewdude 11mo ago
    > that is governed by an ultimate goal. I have bad news for you. Again, it's humans.
agumonkey 11mo ago
how do biologist consider virus like replication then ? which is a two-part system, the virus + the host (and even, a dense population of hosts)
- dredmorbius 11mo ago
  Viruses are considered infectious agents rather than life forms per se. <https://en.wikipedia.org/wiki/Introduction_to_viruses https://en.wikipedia.org/wiki/Introduction_to_viruses>
  - nearbuy 11mo ago
    Not sure why you linked that particular article, as it does not mention anywhere whether viruses are alive (though it implies they're alive with the sentence "Vaccines may consist of either live or killed viruses"). They are infectious agents, but many life forms are infectious agents.
    - dredmorbius 11mo ago
      That article (and the more general article on viruses) both pointedly avoid referring to viruses as organisms, "any living thing that functions as an individual". <https://en.wikipedia.org/wiki/Organism https://en.wikipedia.org/wiki/Organism> Which specifically addresses edge cases including viruses, which "are not typically considered to be organisms, because they are incapable of autonomous reproduction, growth, metabolism, or homeostasis". <https://en.wikipedia.org/wiki/Organism#Viruses https://en.wikipedia.org/wiki/Organism#Viruses> Specifically, viruses have no innate metabolism, or energy-producing chemical reactions. <https://en.wikipedia.org/wiki/Metabolism https://en.wikipedia.org/wiki/Metabolism> The terms "live" and "killed" have historical origins, but would better be read as "active" or "deactivated", and the immediately succeeding sentence clarifies this: "Live vaccines contain weakened forms of the virus, but these vaccines can be dangerous when given to people with weak immunity." For more on the distinction see: <https://www.biologynotes.in/2024/03/difference-between-live-attenuated-and-killed-vaccine.html https://www.biologynotes.in/2024/03/difference-between-live-...>. And yes, there are infectious agents which also happen to be organisms, such as bacteria, amoebas, funguses, etc. Tuberculosis (Mycobacterium tuberculosis), many stomach ulcers (Helicobacter pylori), botulism (Clostridium botulinum), and e. coli poisoning (Escherichia coli) are all infectious disease caused by bacteria. Giardiasis is a G-I infection of the Giardia amoeba. There are numerous fungal infections (many UTI infections, athlete's foot, jock itch, nail infections). Further down the non-life infectious agent chain are prion diseases such as Transmissible spongiform encephalopathy ("mad cow" disease in cattle, "Creutzfeldt–Jakob disease", amongst others). These are literally misfolded proteins, which lack not only metabolism but any genetic material (DNA, RNA), but still propagate. More on infectious agents, a/k/a pathogens: <https://en.wikipedia.org/wiki/Pathogen https://en.wikipedia.org/wiki/Pathogen>.
- thelaxiankey 11mo ago
  def not life. there is no sense in which a virus... 'does' anything, it's not agentic. it's kind of like a free-floating loaded spring.
  - agumonkey 11mo ago
    ok, i get that, and now is a bacteria considered more agentic than a virus then ? (that's a bit of a side-question sorry). bacterias at least reproduce on their own so they check all the boxes.
- mncharity 11mo ago
  First, context: a "life/not-life" distinction is far more "science" than science - widespread in "science" education, but rarely comes up in science research. (Might be interesting to create a list of similar?) Why the emphasis there... I don't know - perhaps because we teach by memorizing definitions and lists, not by learning design spaces and their landmarks? Or at least by giving exemplars without characterizing variance. One of the few places I've seen it come up in science, was ecosystem multi-scale simulation software. Where virus was squarely in the heritable characteristics under selection pressure ("life") bucket, rather than abiotic or biogenic. Informal "do you think of viruses as alive?" seems to vary by field. I've seen a marine bio labs be overwhelmingly yes. I've been told medical immunology leans no. But it seems more social-media engagement question than research question or synthesis.
rbartelme 11mo ago
> Life's two most fundamental properties are homeostasis and reproduction. > The loss of these two combined with its parasitic nature makes this cell a form on non-life. This is a decidedly Eukaryote-centric take. Homeostasis in higher mammals is a complex network of genes -> RNA -> proteins -> metabolic pathways Reproduction is also far more simple in organisms with binary fission cellular division. A more appropriate scientific term would be obligate commensalism vs. "parasitic". That actually encapsulates their need for metabolic precursors from the host, but allows for tRNA, rRNA, origin of replication, etc...present in the organism's genome.
nearbuy 11mo ago
You're being rigid about your preferred definition of life, but for what purpose? What is gained by categorizing this as strictly non-living? Wikipedia on the definition of life: > Since there is no consensus for a definition of life, most current definitions in biology are descriptive. Life is considered a characteristic of something that preserves, furthers or reinforces its existence in the given environment. This implies all or most of the following traits: [list of seven common traits of life]

Life's two most fundamental properties are homeostasis and reproduction. The loss of these two combined with its parasitic nature makes this cell a form on non-life.

anothernewdude 11mo ago

Lots of types of life give up on homeostasis along particular dimensions because the environment is doing it well enough. Viruses do reproduce. If you say "well not by themselves" neither do humans.

tsoukase 11mo ago
No life exists "by themselves". Self-replication means using only its own DNA and not mangling with other's. Virii are not only parasites but dead matter (a ribonucl molecule surrounded by proteins that happens to stick to other cells, like dirt on the skin). Gut microbioma is parasite. There is another life property that this object does not fulfill and is called Teleonomia, that is governed by an ultimate goal.
- anothernewdude 11mo ago
  > that is governed by an ultimate goal. I have bad news for you. Again, it's humans.

agumonkey 11mo ago

how do biologist consider virus like replication then ? which is a two-part system, the virus + the host (and even, a dense population of hosts)

dredmorbius 11mo ago
Viruses are considered infectious agents rather than life forms per se. <https://en.wikipedia.org/wiki/Introduction_to_viruses https://en.wikipedia.org/wiki/Introduction_to_viruses>
- nearbuy 11mo ago
  Not sure why you linked that particular article, as it does not mention anywhere whether viruses are alive (though it implies they're alive with the sentence "Vaccines may consist of either live or killed viruses"). They are infectious agents, but many life forms are infectious agents.
  - dredmorbius 11mo ago
    That article (and the more general article on viruses) both pointedly avoid referring to viruses as organisms, "any living thing that functions as an individual". <https://en.wikipedia.org/wiki/Organism https://en.wikipedia.org/wiki/Organism> Which specifically addresses edge cases including viruses, which "are not typically considered to be organisms, because they are incapable of autonomous reproduction, growth, metabolism, or homeostasis". <https://en.wikipedia.org/wiki/Organism#Viruses https://en.wikipedia.org/wiki/Organism#Viruses> Specifically, viruses have no innate metabolism, or energy-producing chemical reactions. <https://en.wikipedia.org/wiki/Metabolism https://en.wikipedia.org/wiki/Metabolism> The terms "live" and "killed" have historical origins, but would better be read as "active" or "deactivated", and the immediately succeeding sentence clarifies this: "Live vaccines contain weakened forms of the virus, but these vaccines can be dangerous when given to people with weak immunity." For more on the distinction see: <https://www.biologynotes.in/2024/03/difference-between-live-attenuated-and-killed-vaccine.html https://www.biologynotes.in/2024/03/difference-between-live-...>. And yes, there are infectious agents which also happen to be organisms, such as bacteria, amoebas, funguses, etc. Tuberculosis (Mycobacterium tuberculosis), many stomach ulcers (Helicobacter pylori), botulism (Clostridium botulinum), and e. coli poisoning (Escherichia coli) are all infectious disease caused by bacteria. Giardiasis is a G-I infection of the Giardia amoeba. There are numerous fungal infections (many UTI infections, athlete's foot, jock itch, nail infections). Further down the non-life infectious agent chain are prion diseases such as Transmissible spongiform encephalopathy ("mad cow" disease in cattle, "Creutzfeldt–Jakob disease", amongst others). These are literally misfolded proteins, which lack not only metabolism but any genetic material (DNA, RNA), but still propagate. More on infectious agents, a/k/a pathogens: <https://en.wikipedia.org/wiki/Pathogen https://en.wikipedia.org/wiki/Pathogen>.
thelaxiankey 11mo ago
def not life. there is no sense in which a virus... 'does' anything, it's not agentic. it's kind of like a free-floating loaded spring.
- agumonkey 11mo ago
  ok, i get that, and now is a bacteria considered more agentic than a virus then ? (that's a bit of a side-question sorry). bacterias at least reproduce on their own so they check all the boxes.
mncharity 11mo ago
First, context: a "life/not-life" distinction is far more "science" than science - widespread in "science" education, but rarely comes up in science research. (Might be interesting to create a list of similar?) Why the emphasis there... I don't know - perhaps because we teach by memorizing definitions and lists, not by learning design spaces and their landmarks? Or at least by giving exemplars without characterizing variance. One of the few places I've seen it come up in science, was ecosystem multi-scale simulation software. Where virus was squarely in the heritable characteristics under selection pressure ("life") bucket, rather than abiotic or biogenic. Informal "do you think of viruses as alive?" seems to vary by field. I've seen a marine bio labs be overwhelmingly yes. I've been told medical immunology leans no. But it seems more social-media engagement question than research question or synthesis.

rbartelme 11mo ago

> Life's two most fundamental properties are homeostasis and reproduction. > The loss of these two combined with its parasitic nature makes this cell a form on non-life. This is a decidedly Eukaryote-centric take. Homeostasis in higher mammals is a complex network of genes -> RNA -> proteins -> metabolic pathways Reproduction is also far more simple in organisms with binary fission cellular division. A more appropriate scientific term would be obligate commensalism vs. "parasitic". That actually encapsulates their need for metabolic precursors from the host, but allows for tRNA, rRNA, origin of replication, etc...present in the organism's genome.

nearbuy 11mo ago

You're being rigid about your preferred definition of life, but for what purpose? What is gained by categorizing this as strictly non-living? Wikipedia on the definition of life: > Since there is no consensus for a definition of life, most current definitions in biology are descriptive. Life is considered a characteristic of something that preserves, furthers or reinforces its existence in the given environment. This implies all or most of the following traits: [list of seven common traits of life]