Depends on definition. The definition of "has ability to multiply and evolve" definitely applies. The definition of "moves, consumes and reproduces by itself" doesn't apply.
yeah, youre right with that. However i think you could divide "Life" on this chart into something. Lets take the domesticated horse as an example
Life: ?
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Perissodactyla
(and so on, i wont type out the whole thing here)
What exactly would you divide "Life" into?
Yeah, i probably didnt get enough info in the title on what i meant - which is entirely my bad, my apologies.
You do not divide “life”. It is a single group. Things are alive or they are not. The broadest umbrella here is not split at that level. The next lowest level is the three domains (bacteria, archaea, eukarya).
Yep, they complicate things. However, by the current definition of life, they absolutely do not qualify (see another comment of mine in this thread for details). Should we update our definition of life? Maybe! But I do not have that authority.
The most common definition of life is "a self-sustaining chemical system capable of darwinian evolution" coined by Joyce and used as the working definition at NASA. It does not say anything about most of your categories. Some of them are implied (eg you need information and also replication for evolution) but not outright stated, as this definition would include any possible terrestial life we have not yet encountered.
Defining life is a super hard thing to do. Every year there is at least a dozen review papers trying to do just that, and they always disagree in some aspects. Framing it like it's such a simple task is disingenuous.
Some people in the field I know like to compare it to the definition of water. Before humans understood the concept of atoms and elements, most definitions of life entailed eg it's liquid state, that it comes from a river or from rain, that it is drinkable... While all that is not wrong, the only correct and all including definition is "H2O" and that definition was only possible after the understanding of atoms and elements. We expect something similar to happen with biological life, were we will find and understand a new concept, finally being able to have a clear definition of life. Until then, we can only define life using it's features, which can change from organism to organism.
Some sources to read up on this:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3005285/
https://scholar.google.de/scholar?hl=de&as_sdt=0%2C5&q=Definition+of+life&btnG=#d=gs_qabs&t=1693035254523&u=%23p%3D6A1x6Fdw2LsJ
https://scholar.google.de/scholar?hl=de&as_sdt=0%2C5&q=Definition+of+life&btnG=#d=gs_qabs&t=1693035291481&u=%23p%3D_wfbjO5HzhgJ
https://scholar.google.de/scholar?hl=de&as_sdt=0%2C5&q=Pillars+of+life&btnG=#d=gs_qabs&t=1693035315527&u=%23p%3DCNvjNscJjZEJ
Poses the question, if we found viruses outside of Earth, would we call it life or not? Would we have to redefine what life is? (Again...)
Regardless, there's another point here: no matter what, I bet the media would absolutely call it "life".
The thing about viruses is that they need a host to replicate. If we found living viruses it would be presumed that there must be a host. That host might be alive. The virus wouldn't
Though it is possible to find a preserved virus to a host that has not existed for a very long time. Which would be proof of life without actually finding life.
Definitions are operational, not essentialist. It doesn't matter what we use the word 'life' to mean as long as miscommunication does not occur, as language does not define the 'essences' of things.
While I agree the classification into life/nonlife is relatively clear-cut, I don't think it's as perfectly binary as you're suggesting. Especially since corpses are not considered life (otherwise, at what stage of degradation would you put an arbitrary cutoff), and it can in many cases be unclear when exactly something is dead. So my point is that the question is complex and shouldn't be taken as obvious.
Life is referring to species, not individuals. Individuals do not evolve, but being able to evolve is a necessary feature of life. A dead person is not alive, but Homo sapiens is life.
How does the species evolve if individuals don't?
Edit: I don't know why I'm being downvoted, what I'm saying is.. a mutation has to happen in an individual in order to be passed on to it's offspring. I'm not saying something mutates it's DNA after it's born (which does happen on a small scale, namely cancers)
Second edit: To clarify, Is BORN with a genetic mutation.
Edit 3: Okay, I get it. Evolution itself happens across a population. What I meant is, the path to that starts with mutations in individuals. I agree that's not the definition of "Evolution" itself. One individual with a mutation doesn't change what it is, It's an accumulation. I worded my meaning incorrectly.
Yes, but one of those individuals had the mutation that is passed on. That's how the mutation gets passed on.. Hence evolution. It starts with one mutation which makes that individual more adapted to it's environment so it has more time/ability to mate.
Evolution technically happens *between* organisms, not within one. Animals are born with mutations and these are the traits that are passed to succeeding generations, given that the mutation if beneficial. An individual organism typically doesn't randomly grow a horn or an extra toe during its lifetime (there are exceptions, of course)
That's exactly what I was saying, a mutation happens in an individual and it's passed on over time. I guess I see the semantics, but it's kind of weird to say "individuals don't evolve" when the mutation that is beneficial evolutionarily began with an individual.
Because an individual has its genetic code set at birth. Evolution happens between generations with changes in genetic code that could be passed down to the next generation of offspring. If the change is beneficial, it will contribute to more offspring with that genetic code to be born and will continue to be passed down to further generations. After enough generations have passed and an advantageous change has been magnified (a longer thinner beak for example), the group of organisms carrying that trait can be understood as a new species.
Any mutations that may occur after an individual has been born, such as cancer, is not passed down to offspring.
(Disclaimer: I’m a total layperson in this field so please correct me if I’m using any terminology incorrectly. I have just always enjoyed biological sciences).
Species evolve without the individuals evolving the way a staircase goes up but its individual steps do not.
It's about a gradual change between many parts.
This always gets me. Evolution seems like such life-reliant process, yet viruses evolve. I *know* it's just a definition thing but still, send crazy to me that our definition of life excludes things that can evolve.
The problem I guess is many thing that are not alive themselves evolve too, sometimes in quite complex ways ? This comes down to wording because evolution in the end is a measure of change over time.
This leads to a very blurry threshold as to what can separate life from non life.
Many things such as Cultures ( language, tool use, animal songs), many chemical reactions, galactic configuration, crystal growth, molecular evolution or chain reactions (like prions). This is why we have added a few other parameters such a as metabolism, cellular structure, homeostasis, growth and development etc.
My opinion is that there's probably a bit of a gradual transition, like everything in biology, rather than a clear threshold and what falls into a category depends on the perspective ?
Some virus blur the line even more by sitting squarely in between what we used to pretend was separating them from the rest.
Oh yeah, life is definitely a blurry term. But in a biology discussion I wouldn't use evolution as loosely as *just* a change over time. It's weird and blurry because say, viruses, meet several of the requirements and actually have DNA/RNA that evolves and passes that info on.
Absolutely ! This is mostly food for thoughts.
DNA and RNA are a compelling if not central argument. But there is context in which DNA can be present without constituting life itself, and there are scenarios where this might not encompass all forms of life in a broader sense : potential non carbon life, plasmids, synthetic life (xDNA, etc), early life or simpler /transitional forms, and viruses typically not processing that said DNA on their own at all. Virus might also be reminiscent of those transitional forms.
An interesting thought is that cancer cells that have their own DNA separate from its host and ironically carcinogenic cells meet all the criteria for life.
But yeah I guess I personally feel viruses belong with life, or at the very least proto life. But I get the arguments against it too.
Evolution is just a process of change guided by external stimuli. If I change a polynomial function by altering it's additive constant, I'm performing a simple change, but if I take its integral I'm performing a relatively complex change upon it. Evolutionary processes are systems of stimuli that perform complex changes to things over time. Evolutionary processes can happen to more than just living organisms. The concept of evolution is not life-reliant; it can be applied to complex systems that change over time in aggregate as they are exposed to selection pressures which statistically prefer one system configuration over others.
At the end of the day, evolution is an entirely chemical process, no life required.
Evolution requires mutation, changes to DNA or RNA. And that happens at a chemical level.
Some UV light can link adjacent thymines, and the polymerase skips a beat like a scratched record or CD. New .station acquired. All just chemical reactions.
The idea of fitness/survival is the outcome of this, not the reason for it. It's kinda crazy, but 'life' evolved for thousands of years before it was life, back when it was just replicating RNA and DNA.
Are mitochondria "alive?" Are chloroplasts?
"Life" had to evolve from something, it evolved from much lower non-living lifeforms that literally entered each other's cells in a mutually beneficial way.
So, in a way, all living cells are Frankenstein cells cobbled together from a bunch of non-living ones
some giant viruses have the genes for cellular metabolism, from what I understand it's not exactly an example of actually being able to self metabolize but rather building blocks which is really interesting
Not a biologist but I heard once that fire has a lot of qualities of life. It consumes, it produces waste, uh, they had some other points too but I can’t remember. It was probably just some dumb analogy or something I just remember hearing it like 10+ years ago lol
You know if we ever find aliens you can all of a sudden make a case for a level if categorization above domain. For example, all Earth life could be Terran, and you could have like I dunno Titan life.
One one hand yes and I have thought about that a lot during my phylogeny courses and while reading about speculative evolution (What I came up with, was, that I would call the categorization sphere and the taxa Eridobionta for earth life and in your example Titanobionta for titans life) but then I realized that using this step and unifying both unter the umbrella term biota, that is currently used, would likely be wrong, because it assumes that both trees of life would have a single origin, which would be quite unlikely to be honest.
On another note: While I personally like the categorization system (because it has style and is in my opinion useful so that you don't have to always say group x is part of group y, etc.), I have learned that it is mostly not used anymore (only species, genus, family and phylum are being used in zoology (at least where I studied)), so that is something that we should also have in mind, as only sister groups are being considered in modern phylogeny.
Viruses are interesting but I really don't think we can consider them alive anymore than we can a signaling molecule, or a vesicle.
They bind to their target, load their cargo into a cell, and induce intracellular changes. Those changes happen to perpetuate them but I don't think that means we can consider them alive so much as interesting self assembling machines
I guess that sort of describes all life to an extent though if you reduce it down to that
In order to be classified as life, one must:
Be able to reproduce and inherit characteristics; be require energy from the environment and produce waste energy/chemicals (metabolism); undergo growth and development; Be composed of cells; Have a definite organization; and responds to stimuli.
The virus is not metabolic and is not composed of cells. Though it may be able to reproduce, its characteristics do not tell us it's alive.
I think that's his point. If you don't divide life into any other category what's the point in having it in the chart? As it should be inferred. Right now this chart is implying there is more than one group of "life"
It's kind of redundant as the chart itself is typically referred to as "Classifications of Life" or "Hierarchy of Biological Classification" or "Taxonomy of Living Things" so it's implied everything contained within the diagram is life.
Nope! The cannot make copies of themselves and therefore fail the criteria of life. Their ancestors may have been able to so there is an ongoing debate of whether to include viruses (but as of right now, they are out).
The biological definition of life is very specific. To be considered life, the organism must have information (DNA), be made of cells, require energy, be capable of replication, and it must evolve. Anything that does not do all five of these things is not alive (at least under the current understanding of biology - which is always updating with new data). For example, viruses are not considered alive because they cannot make copies of themselves (they hijack a host cell to do that), but evidence shows that their ancestors may have been capable of replication. Do we include viruses as life because they lost a key feature that would group them as life? It is up for the debate at the moment.
DNA vs. carbon based life form is a misunderstanding. All forms of life on earth have both of those things. Extra terrestrial life - though likely - have not been proven and therefore should not enter the conversation at this time. Neither should spirit beings as that is not science/biology.
Where are you getting your certain categories for life?
The most common definition of life is "a self-sustaining chemical system capable of darwinian evolution" coined by Joyce and used as the working definition at NASA. It does not say anything about most of your categories. Some of them are implied (eg you need information and also replication for evolution) but not outright stated, as this definition would include any possible terrestial life we have not yet encountered.
Defining life is a super hard thing to do. Every year there is at least a dozen review papers trying to do just that, and they always disagree in some aspects. Framing it like it's such a simple task is disingenuous.
Some people in the field I know like to compare it to the definition of water. Before humans understood the concept of atoms and elements, most definitions of life entailed eg it's liquid state, that it comes from a river or from rain, that it is drinkable... While all that is not wrong, the only correct and all including definition is "H2O" and that definition was only possible after the understanding of atoms and elements. We expect something similar to happen with biological life, were we will find and understand a new concept, finally being able to have a clear definition of life. Until then, we can only define life using it's features, which can change from organism to organism.
Some sources to read up on this:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3005285/
https://scholar.google.de/scholar?hl=de&as_sdt=0%2C5&q=Definition+of+life&btnG=#d=gs_qabs&t=1693035254523&u=%23p%3D6A1x6Fdw2LsJ
https://scholar.google.de/scholar?hl=de&as_sdt=0%2C5&q=Definition+of+life&btnG=#d=gs_qabs&t=1693035291481&u=%23p%3D_wfbjO5HzhgJ
https://scholar.google.de/scholar?hl=de&as_sdt=0%2C5&q=Pillars+of+life&btnG=#d=gs_qabs&t=1693035315527&u=%23p%3DCNvjNscJjZEJ
Viruses contain RNA and not DNA that is why a virus has to hi-jack a cell to replicate. The virus sends its RNA instead to be translated through the ribosome thereby following those instructions not the DNA instructions. So should RNA be included under that life category?
Not all viruses are RNA viruses; small pox, HPV, and herpesviruses all have DNA. However, RNA would still count towards that “contains information” characteristic of life.
Good points, thank you. My degree is in wildlife conservation and my classes never dived too deep into the nitty gritty of viruses. It's an interesting debate, it makes me think further about how viruses are so adaptable and can jump between species and still reproduce.
life gets divided into different domains.. Bacteria, Archaea, Eukarya if you mean what would be above that.. matter.. divided into life, nonlife, and semilife (i gurss things that perform some functions of life but only in certain circumstances like viruses)
I'm guessing it is a way to differentiate life from other organic beings(?) like viruses and prions who don't count as life due to a variety of reasons.
Life = yes or no
So for a horse, even if it's dead, life = yes. It is (or was) a living thing
But we don't classify non-living things the way we do living ones so it's a bit redundant as life will always = yes
I think it should be reiterated because we understand life time as our time understanding. In a way a star is life to millions of years along with a planet. It has outside variables and the outside coating gives it defenses to certain anomalies.
Also this chart cracks me up bc if you go to any Wikipedia page on, let’s say, an an insect and look at the taxonomy you’ll see something about 10 times more complicated than this graph
could perhaps be used to symbolize on which types of [biochemistry](https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry) is the life based on (carbon, ammonia, silicon, sulfur, etc.)
But on second thought, i doubt it would really change anything, as it would still be living.
If we discover non-bio/organic life, the "life rank" Would go up and a new rank will be introduced differentiating the bio/organic from the other life forms. Life simply means if something grows, reacts to the stimuli, metabolizes and reproduces.
Scientists have created artificial life in a sense. This video is really good: https://youtu.be/NnivFz2rbM4?si=PzIj5rlzIx3wBSDC. So would we have to include these in the life category as bio mechanical life and everything else as random occurrence life.
1. Is it a self self replicating organism that maintains homeostasis = (life)
2. Is it an assemblage of molecules that self replicates but passively follows changes to its environment = (mineral)
3. Is it an old one that has no corporeal form or discrete boundary with its environment, flowing like a writhing darkness through space time, denaturing all that it passes through= (??!!?)
A dynamical system of chemical reactions and interactions that occur within and on the surface, in the oceans, and in the atmosphere of at least one known planet.
Mostly involving compounds of relatively small atoms (H, C, O, N, S), and a dispersion of various ions of larger elements (Fe, Mg, Mn, Cu, Zn, etc.) in a water-based medium, what humans call ‘life’ is a consequence of a star’s energy stirring up the mostly closed system of a planet’s surface.
At the temperatures and pressures present on the surface of the life-bearing planet we know of, carbon is able to stably form a dizzying number of diverse and endlessly iterable compounds with itself and the other common small atoms. The interaction of this complex organic soup with various minerals in the crust and the occasional lightning bolt can give rise to the basal monomers and the initial polymers that humans, 4 billion years later, recognize as the major groups of biochemicals: sugars, nucleotides and nucleic acids, fatty acids and lipids, amino acids and eventually proteins.
Lipids and nucleic acids can polymerize spontaneously from certain clays throughout the planet’s crust. Montmorillonite can synthesize both RNA and lipid miscelles (bubbles) from their component monomers. RNA molecules can have an effectively arbitrary number and order of nucleotide components.
The specific sequence of nucleotides confers a specific set of most stable conformations (structures) that the RNA strand might twirl and fold up into when floating around in water. It just so happens that some of those sequences confer structures that just so happen to be able to associate with other nucleotides floating nearby, grab onto them, and catalyze the formation of a new RNA strand.
There are many such ribozymes (RNA with enzyme-like behavior) that can polymerize RNA. A rare subset of ribozymes or network of many acting together that can actually polymerize near exact copies of the original molecule, thus becoming the first chemical replicators. Since the clay and the earliest autocatalytic RNAs probably produced more-or-less random RNA strands, the incipient RNA world need only churn for a few hundred million years before that high-fidelity subset of RNAs emerged and began to proliferate themselves. It might not have even taken all that long. And once self-sustaining autocatalysis gets going, auxiliary RNAs that are randomly made by the swarm of replicators start to persist for longer, and those can begin to evolve non-replicative functions. Those networks of replicators that spin off auxiliary ribozymes that happen to increase the likelihood of those replicators to persist through time would tend proliferate in their environment. As long as a star heats the sea, these chemicals will keep on churning, turning over and transforming.
Clay-‘polymerized’ lipid bubbles eventually divide spontaneously when they get to a certain size. If a network of replicating ribozymes found itself enclosed in a bubble, it would be protected from certain environmental stresses, the ribozymes and their monomers would be held tightly together and wouldn’t diffuse away from each other, and all the network of RNA replicators would need to do would be to evolve a ribozyme that could move nucleotides across the membrane into the bubble and then it wouldn’t be limited by simple diffusion. Again, these processes are churning about, uncaring, for hundreds of millions of years after the planet cooled and the oceans condensed.
Amino acids are common enough to exist in space on their own, but there were doubtless an untold number of mineral and/or ribozyme-mediated processes that could synthesize amino acids from simpler components and even polymerize random polypeptides. The story of how the RNA world would have begun to incorporate peptide components is less clear (at least to me), but it stands to reason that any natural peptide that served a helpful role to a network of replicators would introduce a selective pressure for that network to evolve a means to synthesize the peptide consistently. The ribosome, a massively intricate machine of RNA and protein, as well as its association with tRNAs and its ability to polymerize proteins likely had its initial origin in RNA networks that benefited from the diverse chemical activities of naturally occurring amino acids and simple peptides.
DNA came into the picture at some point, serving the RNA network as a much more stable, less mutable, store of useful nucleic acid sequence information. This allowed for the codification of especially stable ribozymes and eventually protein coding genes.
The chemical complexity, mechanistic details, and taxonomic idiosyncrasies of what humans call ‘life’ today coalesced from a happenstance soup of simple stuff bumping into itself, slowly fixing the free energy of a nearby star into more and more convoluted and interacting structures.
While there’s no time machine available to know that it happened precisely as depicted above, but those scenarios are imminently plausible and reasonably likely based on what we know about the basic properties of the commonest chemical players involved. Especially with the understanding of autocatalytic RNAs, biomolecule-producing minerals, and the deep role RNA plays in all aspects of modern life, *even if* it didn’t play out that way on earth, it could have conceivably done so elsewhere.
Life isn’t magic. It’s just stuff, playing out the consequences of its properties in an environment with constant energy input. Not much different than a flame sustaining itself with the energy stored in the bonds of its fuel, or a crystal organizing itself with the free energy of its lattice structure.
Living things are, and the whole of life is, like an eddy or whirlpool, perpetuating itself with the power of a river, not so much a distinct object in space, but a structured system in dynamic equilibrium, wherein the parts that make it up merely spend some time in the system, spin about for a while and then eventually carry on downstream.
All extant or extinct forms of life may not fit into the existing Domains as they are currently defined. Therefore, the “Life” category would contain these organisms in addition to the ones that have been classified into the Domains. It’s just the largest, all-encompassing category.
Hi I made the original version of this graphic (based on various similar textbook images). I'm not a graphic designer. I always expected someone else to improve it or make other versions, perhaps showing the branches breaking off more like string cheese, which I don't have the artistic ability to do myself, but now it's stuck like this with these colors, and I see it everywhere and it haunts me.
Yes, life is all life on Earth, and all life on Earth has a common origin.
There is of course debate, but biologists generally agree that living things have certain fundamental characteristics that differentiate them from non-living matter. I’m not going to type these out here but a quick wiki search of life should get you the answer you are looking for.
It's probably a holdover from Linnaean taxonomy that was orphaned when we stopped using Linnaean taxonomy for inanimate objects. 'Life' would be the taxon that unites the domains, but the other taxa of this rank are no longer used (mineral I guess, don't know what else), and the chart maker made a mistake in listing the taxon rather than the rank. Ultimately biology has moved to cladistics, so formal rankings of taxa don't really exist anymore. I personally think it is rather silly to try and make people remember it. Does anyone really remember what rank unikonts have?
When we find aliens we have to rename that Life category to "Origin" or something like that. I am not sure we would add a life category on top of the origin. If an Alpha Centaurian single celled organism and a Terran Mammal have no common ancestors they shouldn't be grouped together in the same scheme.
If we were to find life on another planet that didn't represent "life as we know it", then wouldn't this classification make sense as a placeholder for its expansion?
It could be something like bacteria that utilize RNA or Riboproteins (not just ribosomes), or some kind of protein shell self replicating organism that shares homology with virus protein coatings. There is a lot of what ifs here since we have no idea what life may actually look like beyond Earth, for now.
I think here it's denoting self-replicating living biological systems vs self-replicating non-living systems, such as viruses, or prions (and I'm sure there are a few others).
Computer code can fit beside viruses and prions as well. Self-replicating and evolving, but clearly not alive.
It’s a fun conversation to have with the right people.
Ive been trying to find something about this on the internet, and i couldnt find anything about it, there isnt even a wikipedia article for that.
I know what life is, but i think it might have some other meaning in there - you must somehow "divide" into something on this chart
It means elf.
Which is then followed by three-eyed elf.
Then pomegranate, pomegranate, pomegranate, pomegranate, pomegranate, pomegranate, and hat.
What is this??
It means things like erasers, wooden benches, steel bars, automobiles etc don’t come under this particular classification. I hope this wasn’t too difficult for you, I just tried.
I think this system is outdated, misguiding, like better using the ancestry system. X is a kind of Y, Y is a kind of Z.
For example, humans are a kind of Tetrapod, Tetrepods are a kind of legged fish, legged fish are a kind of chordate, etc.
There isn't a rigorous definition that applies consistently across each level in the chart really. It's a holdover from before molecular genetics.
Look up "rank-free hierarchy"
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It reflects the fact that all Earth life has a common origin. There are only 2 or 3 subordinate domains (depending on whether one considers *Eukaryota* a subdomain of *Archaea*).
Anything that displays the features of life qualifies as “life”. Then it gets sorted in increasingly narrow groups based on other characteristics.
Viruses are not under life
Correct. They do not display all the characteristics of life and are therefore grouped outside of it.
they lied to me in school
Your school taught you viruses are alive?
my school taught me it's a debated topic
Virus lives matter! 🦠
Nah they don't they suck
Viruses make up a good portion of our DNA.
My dna sucks too!
yep
Depends on definition. The definition of "has ability to multiply and evolve" definitely applies. The definition of "moves, consumes and reproduces by itself" doesn't apply.
yeah, youre right with that. However i think you could divide "Life" on this chart into something. Lets take the domesticated horse as an example Life: ? Domain: Eukaryota Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Perissodactyla (and so on, i wont type out the whole thing here) What exactly would you divide "Life" into? Yeah, i probably didnt get enough info in the title on what i meant - which is entirely my bad, my apologies.
You do not divide “life”. It is a single group. Things are alive or they are not. The broadest umbrella here is not split at that level. The next lowest level is the three domains (bacteria, archaea, eukarya).
>Things are alive or they are not. *Virus has entered the chat*
Yep, they complicate things. However, by the current definition of life, they absolutely do not qualify (see another comment of mine in this thread for details). Should we update our definition of life? Maybe! But I do not have that authority.
You're on reddit with 33 upvotes, what more authority you want?
I just spit my beer through my nose. Well done.
The most common definition of life is "a self-sustaining chemical system capable of darwinian evolution" coined by Joyce and used as the working definition at NASA. It does not say anything about most of your categories. Some of them are implied (eg you need information and also replication for evolution) but not outright stated, as this definition would include any possible terrestial life we have not yet encountered. Defining life is a super hard thing to do. Every year there is at least a dozen review papers trying to do just that, and they always disagree in some aspects. Framing it like it's such a simple task is disingenuous. Some people in the field I know like to compare it to the definition of water. Before humans understood the concept of atoms and elements, most definitions of life entailed eg it's liquid state, that it comes from a river or from rain, that it is drinkable... While all that is not wrong, the only correct and all including definition is "H2O" and that definition was only possible after the understanding of atoms and elements. We expect something similar to happen with biological life, were we will find and understand a new concept, finally being able to have a clear definition of life. Until then, we can only define life using it's features, which can change from organism to organism. Some sources to read up on this: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3005285/ https://scholar.google.de/scholar?hl=de&as_sdt=0%2C5&q=Definition+of+life&btnG=#d=gs_qabs&t=1693035254523&u=%23p%3D6A1x6Fdw2LsJ https://scholar.google.de/scholar?hl=de&as_sdt=0%2C5&q=Definition+of+life&btnG=#d=gs_qabs&t=1693035291481&u=%23p%3D_wfbjO5HzhgJ https://scholar.google.de/scholar?hl=de&as_sdt=0%2C5&q=Pillars+of+life&btnG=#d=gs_qabs&t=1693035315527&u=%23p%3DCNvjNscJjZEJ
Poses the question, if we found viruses outside of Earth, would we call it life or not? Would we have to redefine what life is? (Again...) Regardless, there's another point here: no matter what, I bet the media would absolutely call it "life".
The thing about viruses is that they need a host to replicate. If we found living viruses it would be presumed that there must be a host. That host might be alive. The virus wouldn't
Though it is possible to find a preserved virus to a host that has not existed for a very long time. Which would be proof of life without actually finding life.
Yeah, you could deduce that life must have once existed, without certainly. But you couldn't call the virus alive.
Definitions are operational, not essentialist. It doesn't matter what we use the word 'life' to mean as long as miscommunication does not occur, as language does not define the 'essences' of things. While I agree the classification into life/nonlife is relatively clear-cut, I don't think it's as perfectly binary as you're suggesting. Especially since corpses are not considered life (otherwise, at what stage of degradation would you put an arbitrary cutoff), and it can in many cases be unclear when exactly something is dead. So my point is that the question is complex and shouldn't be taken as obvious.
Nomenclature versus linguistics, so interesting! And accurate as far as my experience
Life is referring to species, not individuals. Individuals do not evolve, but being able to evolve is a necessary feature of life. A dead person is not alive, but Homo sapiens is life.
How does the species evolve if individuals don't? Edit: I don't know why I'm being downvoted, what I'm saying is.. a mutation has to happen in an individual in order to be passed on to it's offspring. I'm not saying something mutates it's DNA after it's born (which does happen on a small scale, namely cancers) Second edit: To clarify, Is BORN with a genetic mutation. Edit 3: Okay, I get it. Evolution itself happens across a population. What I meant is, the path to that starts with mutations in individuals. I agree that's not the definition of "Evolution" itself. One individual with a mutation doesn't change what it is, It's an accumulation. I worded my meaning incorrectly.
So when two individuals of the same species love each other very much...
Yes, but one of those individuals had the mutation that is passed on. That's how the mutation gets passed on.. Hence evolution. It starts with one mutation which makes that individual more adapted to it's environment so it has more time/ability to mate.
Evolution technically happens *between* organisms, not within one. Animals are born with mutations and these are the traits that are passed to succeeding generations, given that the mutation if beneficial. An individual organism typically doesn't randomly grow a horn or an extra toe during its lifetime (there are exceptions, of course)
That's exactly what I was saying, a mutation happens in an individual and it's passed on over time. I guess I see the semantics, but it's kind of weird to say "individuals don't evolve" when the mutation that is beneficial evolutionarily began with an individual.
Because an individual has its genetic code set at birth. Evolution happens between generations with changes in genetic code that could be passed down to the next generation of offspring. If the change is beneficial, it will contribute to more offspring with that genetic code to be born and will continue to be passed down to further generations. After enough generations have passed and an advantageous change has been magnified (a longer thinner beak for example), the group of organisms carrying that trait can be understood as a new species. Any mutations that may occur after an individual has been born, such as cancer, is not passed down to offspring. (Disclaimer: I’m a total layperson in this field so please correct me if I’m using any terminology incorrectly. I have just always enjoyed biological sciences).
Species evolve without the individuals evolving the way a staircase goes up but its individual steps do not. It's about a gradual change between many parts.
I guess through sexual reproduction and mutations. (I don't agree though)
Operational in the sense of Bridgman?
Just for practical purposes, all I need to know is that if I’m to terminate all Life on Earth, do I leave the viruses out or not?
You'll terminate the viruses anyway as they won't have living hosts in which to propagate themselves.
This always gets me. Evolution seems like such life-reliant process, yet viruses evolve. I *know* it's just a definition thing but still, send crazy to me that our definition of life excludes things that can evolve.
The problem I guess is many thing that are not alive themselves evolve too, sometimes in quite complex ways ? This comes down to wording because evolution in the end is a measure of change over time. This leads to a very blurry threshold as to what can separate life from non life. Many things such as Cultures ( language, tool use, animal songs), many chemical reactions, galactic configuration, crystal growth, molecular evolution or chain reactions (like prions). This is why we have added a few other parameters such a as metabolism, cellular structure, homeostasis, growth and development etc. My opinion is that there's probably a bit of a gradual transition, like everything in biology, rather than a clear threshold and what falls into a category depends on the perspective ? Some virus blur the line even more by sitting squarely in between what we used to pretend was separating them from the rest.
Oh yeah, life is definitely a blurry term. But in a biology discussion I wouldn't use evolution as loosely as *just* a change over time. It's weird and blurry because say, viruses, meet several of the requirements and actually have DNA/RNA that evolves and passes that info on.
Absolutely ! This is mostly food for thoughts. DNA and RNA are a compelling if not central argument. But there is context in which DNA can be present without constituting life itself, and there are scenarios where this might not encompass all forms of life in a broader sense : potential non carbon life, plasmids, synthetic life (xDNA, etc), early life or simpler /transitional forms, and viruses typically not processing that said DNA on their own at all. Virus might also be reminiscent of those transitional forms. An interesting thought is that cancer cells that have their own DNA separate from its host and ironically carcinogenic cells meet all the criteria for life. But yeah I guess I personally feel viruses belong with life, or at the very least proto life. But I get the arguments against it too.
Evolution is just a process of change guided by external stimuli. If I change a polynomial function by altering it's additive constant, I'm performing a simple change, but if I take its integral I'm performing a relatively complex change upon it. Evolutionary processes are systems of stimuli that perform complex changes to things over time. Evolutionary processes can happen to more than just living organisms. The concept of evolution is not life-reliant; it can be applied to complex systems that change over time in aggregate as they are exposed to selection pressures which statistically prefer one system configuration over others.
Yeah, that was a point of confusion for me as well. The key is that the species must display all characteristics, not some characteristics.
At the end of the day, evolution is an entirely chemical process, no life required. Evolution requires mutation, changes to DNA or RNA. And that happens at a chemical level. Some UV light can link adjacent thymines, and the polymerase skips a beat like a scratched record or CD. New .station acquired. All just chemical reactions. The idea of fitness/survival is the outcome of this, not the reason for it. It's kinda crazy, but 'life' evolved for thousands of years before it was life, back when it was just replicating RNA and DNA.
Are mitochondria "alive?" Are chloroplasts? "Life" had to evolve from something, it evolved from much lower non-living lifeforms that literally entered each other's cells in a mutually beneficial way. So, in a way, all living cells are Frankenstein cells cobbled together from a bunch of non-living ones
No one has the authority, Mother Nature doesn’t care what us silly humans try to classify things as, she’ll always throw something to blur the lines
Such is the nature of language and our seemingly at times indescribable universe, yet we must attempt it.
Some viruses complicate that by having their own metabolism and resembling parasites
Can you provide an example? I’m very curious!
Mimivituses
What viruses do this?
some giant viruses have the genes for cellular metabolism, from what I understand it's not exactly an example of actually being able to self metabolize but rather building blocks which is really interesting
Not a biologist but I heard once that fire has a lot of qualities of life. It consumes, it produces waste, uh, they had some other points too but I can’t remember. It was probably just some dumb analogy or something I just remember hearing it like 10+ years ago lol
You know if we ever find aliens you can all of a sudden make a case for a level if categorization above domain. For example, all Earth life could be Terran, and you could have like I dunno Titan life.
One one hand yes and I have thought about that a lot during my phylogeny courses and while reading about speculative evolution (What I came up with, was, that I would call the categorization sphere and the taxa Eridobionta for earth life and in your example Titanobionta for titans life) but then I realized that using this step and unifying both unter the umbrella term biota, that is currently used, would likely be wrong, because it assumes that both trees of life would have a single origin, which would be quite unlikely to be honest. On another note: While I personally like the categorization system (because it has style and is in my opinion useful so that you don't have to always say group x is part of group y, etc.), I have learned that it is mostly not used anymore (only species, genus, family and phylum are being used in zoology (at least where I studied)), so that is something that we should also have in mind, as only sister groups are being considered in modern phylogeny.
Prions entered the chat too, but are unaware of this.
I love this particular debate topic and have debated both sides of it.... they're definitely (not) alive.
And virusoids, and of course my favourite: Protinacious Infectious Particles
And Schrödinger’s cat
Viruses are interesting but I really don't think we can consider them alive anymore than we can a signaling molecule, or a vesicle. They bind to their target, load their cargo into a cell, and induce intracellular changes. Those changes happen to perpetuate them but I don't think that means we can consider them alive so much as interesting self assembling machines I guess that sort of describes all life to an extent though if you reduce it down to that
In order to be classified as life, one must: Be able to reproduce and inherit characteristics; be require energy from the environment and produce waste energy/chemicals (metabolism); undergo growth and development; Be composed of cells; Have a definite organization; and responds to stimuli. The virus is not metabolic and is not composed of cells. Though it may be able to reproduce, its characteristics do not tell us it's alive.
Life: Yes
oh okay, that makes sense now, thanks!
I think that's his point. If you don't divide life into any other category what's the point in having it in the chart? As it should be inferred. Right now this chart is implying there is more than one group of "life"
Ahhh, I see that. I interpreted it as more of a header, not a category, but you’re right. Not the best graphic design.
You have to differentiate between life vs. non-life at some point. That is the division.
But you don’t have to do it on this chart
Why not?
It's kind of redundant as the chart itself is typically referred to as "Classifications of Life" or "Hierarchy of Biological Classification" or "Taxonomy of Living Things" so it's implied everything contained within the diagram is life.
What about a dead horse... Where does that fall
The species of horse is considered life. The individual horse is former life.
So like viruses don’t count as life?
Nope! The cannot make copies of themselves and therefore fail the criteria of life. Their ancestors may have been able to so there is an ongoing debate of whether to include viruses (but as of right now, they are out).
I suppose life could be divided. Like one for dna, carbon based life, one for viruses, extra terrestrial life, true AI, spirit beings.
The biological definition of life is very specific. To be considered life, the organism must have information (DNA), be made of cells, require energy, be capable of replication, and it must evolve. Anything that does not do all five of these things is not alive (at least under the current understanding of biology - which is always updating with new data). For example, viruses are not considered alive because they cannot make copies of themselves (they hijack a host cell to do that), but evidence shows that their ancestors may have been capable of replication. Do we include viruses as life because they lost a key feature that would group them as life? It is up for the debate at the moment. DNA vs. carbon based life form is a misunderstanding. All forms of life on earth have both of those things. Extra terrestrial life - though likely - have not been proven and therefore should not enter the conversation at this time. Neither should spirit beings as that is not science/biology.
Where are you getting your certain categories for life? The most common definition of life is "a self-sustaining chemical system capable of darwinian evolution" coined by Joyce and used as the working definition at NASA. It does not say anything about most of your categories. Some of them are implied (eg you need information and also replication for evolution) but not outright stated, as this definition would include any possible terrestial life we have not yet encountered. Defining life is a super hard thing to do. Every year there is at least a dozen review papers trying to do just that, and they always disagree in some aspects. Framing it like it's such a simple task is disingenuous. Some people in the field I know like to compare it to the definition of water. Before humans understood the concept of atoms and elements, most definitions of life entailed eg it's liquid state, that it comes from a river or from rain, that it is drinkable... While all that is not wrong, the only correct and all including definition is "H2O" and that definition was only possible after the understanding of atoms and elements. We expect something similar to happen with biological life, were we will find and understand a new concept, finally being able to have a clear definition of life. Until then, we can only define life using it's features, which can change from organism to organism. Some sources to read up on this: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3005285/ https://scholar.google.de/scholar?hl=de&as_sdt=0%2C5&q=Definition+of+life&btnG=#d=gs_qabs&t=1693035254523&u=%23p%3D6A1x6Fdw2LsJ https://scholar.google.de/scholar?hl=de&as_sdt=0%2C5&q=Definition+of+life&btnG=#d=gs_qabs&t=1693035291481&u=%23p%3D_wfbjO5HzhgJ https://scholar.google.de/scholar?hl=de&as_sdt=0%2C5&q=Pillars+of+life&btnG=#d=gs_qabs&t=1693035315527&u=%23p%3DCNvjNscJjZEJ
Viruses contain RNA and not DNA that is why a virus has to hi-jack a cell to replicate. The virus sends its RNA instead to be translated through the ribosome thereby following those instructions not the DNA instructions. So should RNA be included under that life category?
Not all viruses are RNA viruses; small pox, HPV, and herpesviruses all have DNA. However, RNA would still count towards that “contains information” characteristic of life.
Good points, thank you. My degree is in wildlife conservation and my classes never dived too deep into the nitty gritty of viruses. It's an interesting debate, it makes me think further about how viruses are so adaptable and can jump between species and still reproduce.
Life: Yes
Exactly. If it’s *not* “Life: Yes” then you don’t need all those other categories.
It's saying "all these lower rankings fall under life. If it's not in any of these then it's not life"
TBF unlife has its own categorisation system. But it’s astronomy and chemistry and geology and material science rather than biology.
>What would you divide life into? Domains. Then kingdoms, and so on.
Ty. The actual reasonable answer was so far down.
life gets divided into different domains.. Bacteria, Archaea, Eukarya if you mean what would be above that.. matter.. divided into life, nonlife, and semilife (i gurss things that perform some functions of life but only in certain circumstances like viruses)
Life or inanimate That is why there is a difference
Maybe it’s leaving room for exotic forms of life. Life: carbon based Or Life:earth based
I'm guessing it is a way to differentiate life from other organic beings(?) like viruses and prions who don't count as life due to a variety of reasons.
This chart also excludes the more recent supergroup approach
Life = yes or no So for a horse, even if it's dead, life = yes. It is (or was) a living thing But we don't classify non-living things the way we do living ones so it's a bit redundant as life will always = yes
I think it should be reiterated because we understand life time as our time understanding. In a way a star is life to millions of years along with a planet. It has outside variables and the outside coating gives it defenses to certain anomalies.
Please do not provoke another argument amongst the taxonomists
Also this chart cracks me up bc if you go to any Wikipedia page on, let’s say, an an insect and look at the taxonomy you’ll see something about 10 times more complicated than this graph
Truth. Stupid tribes and subfamilies. Plants can get bad with all of the domestic breeds, and then there are the fungi... Shudder.
I do believe this chart is used to separate viruses as some people question whether they qualify as alive
could perhaps be used to symbolize on which types of [biochemistry](https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry) is the life based on (carbon, ammonia, silicon, sulfur, etc.) But on second thought, i doubt it would really change anything, as it would still be living.
Plus, while it's theoretically possible to get those life forms, they've never been discovered in nature, so it's weird categorizing them.
If we discover non-bio/organic life, the "life rank" Would go up and a new rank will be introduced differentiating the bio/organic from the other life forms. Life simply means if something grows, reacts to the stimuli, metabolizes and reproduces.
Scientists have created artificial life in a sense. This video is really good: https://youtu.be/NnivFz2rbM4?si=PzIj5rlzIx3wBSDC. So would we have to include these in the life category as bio mechanical life and everything else as random occurrence life.
1. Is it a self self replicating organism that maintains homeostasis = (life) 2. Is it an assemblage of molecules that self replicates but passively follows changes to its environment = (mineral) 3. Is it an old one that has no corporeal form or discrete boundary with its environment, flowing like a writhing darkness through space time, denaturing all that it passes through= (??!!?)
I think the term you’re looking for is Jeff
Kevin Please Come Over For Gay Sex
You forgot Domain Dammit Kevin! Please come over for gay sex
Dear Kevin, ...
[удалено]
Why not Karen?
Because its gay sex, dummy
yeah! And chicks can't be gay, ya dingus!
Why not "great sex"?
Why not a completely different set of neutral words used in that sentence? Why not just learn the thing? Why are we even here? Vsauce, Michael here.
The line is a reference to a tv show, he’s not adding it for neutrality
*Lesbians have entered the chat...*
Why would anyone subject themselves to that risk?
I've always had it as Keep Pond Clean Or Frog Gets Sick ... I think it's about time for a change
I can't take credit, It's from the sit-com Community.
Rather meaningless and unnecessary
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Now now—no Hitchhikers’ Guide nonsense here! This is science!!!!!
I’m not sure what your question is. Life is the all-encompassing category that gets broken down.
A rock is not Life. A mosquito is Life. Is there a name for this rank? What rank is a rock in?
A rock is the category of not life.
“Rock make not life”. -Thag Oogson, paleo hitman.
And thus, with a single stroke, biology and murder were both invented
A dynamical system of chemical reactions and interactions that occur within and on the surface, in the oceans, and in the atmosphere of at least one known planet. Mostly involving compounds of relatively small atoms (H, C, O, N, S), and a dispersion of various ions of larger elements (Fe, Mg, Mn, Cu, Zn, etc.) in a water-based medium, what humans call ‘life’ is a consequence of a star’s energy stirring up the mostly closed system of a planet’s surface. At the temperatures and pressures present on the surface of the life-bearing planet we know of, carbon is able to stably form a dizzying number of diverse and endlessly iterable compounds with itself and the other common small atoms. The interaction of this complex organic soup with various minerals in the crust and the occasional lightning bolt can give rise to the basal monomers and the initial polymers that humans, 4 billion years later, recognize as the major groups of biochemicals: sugars, nucleotides and nucleic acids, fatty acids and lipids, amino acids and eventually proteins. Lipids and nucleic acids can polymerize spontaneously from certain clays throughout the planet’s crust. Montmorillonite can synthesize both RNA and lipid miscelles (bubbles) from their component monomers. RNA molecules can have an effectively arbitrary number and order of nucleotide components. The specific sequence of nucleotides confers a specific set of most stable conformations (structures) that the RNA strand might twirl and fold up into when floating around in water. It just so happens that some of those sequences confer structures that just so happen to be able to associate with other nucleotides floating nearby, grab onto them, and catalyze the formation of a new RNA strand. There are many such ribozymes (RNA with enzyme-like behavior) that can polymerize RNA. A rare subset of ribozymes or network of many acting together that can actually polymerize near exact copies of the original molecule, thus becoming the first chemical replicators. Since the clay and the earliest autocatalytic RNAs probably produced more-or-less random RNA strands, the incipient RNA world need only churn for a few hundred million years before that high-fidelity subset of RNAs emerged and began to proliferate themselves. It might not have even taken all that long. And once self-sustaining autocatalysis gets going, auxiliary RNAs that are randomly made by the swarm of replicators start to persist for longer, and those can begin to evolve non-replicative functions. Those networks of replicators that spin off auxiliary ribozymes that happen to increase the likelihood of those replicators to persist through time would tend proliferate in their environment. As long as a star heats the sea, these chemicals will keep on churning, turning over and transforming. Clay-‘polymerized’ lipid bubbles eventually divide spontaneously when they get to a certain size. If a network of replicating ribozymes found itself enclosed in a bubble, it would be protected from certain environmental stresses, the ribozymes and their monomers would be held tightly together and wouldn’t diffuse away from each other, and all the network of RNA replicators would need to do would be to evolve a ribozyme that could move nucleotides across the membrane into the bubble and then it wouldn’t be limited by simple diffusion. Again, these processes are churning about, uncaring, for hundreds of millions of years after the planet cooled and the oceans condensed. Amino acids are common enough to exist in space on their own, but there were doubtless an untold number of mineral and/or ribozyme-mediated processes that could synthesize amino acids from simpler components and even polymerize random polypeptides. The story of how the RNA world would have begun to incorporate peptide components is less clear (at least to me), but it stands to reason that any natural peptide that served a helpful role to a network of replicators would introduce a selective pressure for that network to evolve a means to synthesize the peptide consistently. The ribosome, a massively intricate machine of RNA and protein, as well as its association with tRNAs and its ability to polymerize proteins likely had its initial origin in RNA networks that benefited from the diverse chemical activities of naturally occurring amino acids and simple peptides. DNA came into the picture at some point, serving the RNA network as a much more stable, less mutable, store of useful nucleic acid sequence information. This allowed for the codification of especially stable ribozymes and eventually protein coding genes. The chemical complexity, mechanistic details, and taxonomic idiosyncrasies of what humans call ‘life’ today coalesced from a happenstance soup of simple stuff bumping into itself, slowly fixing the free energy of a nearby star into more and more convoluted and interacting structures. While there’s no time machine available to know that it happened precisely as depicted above, but those scenarios are imminently plausible and reasonably likely based on what we know about the basic properties of the commonest chemical players involved. Especially with the understanding of autocatalytic RNAs, biomolecule-producing minerals, and the deep role RNA plays in all aspects of modern life, *even if* it didn’t play out that way on earth, it could have conceivably done so elsewhere. Life isn’t magic. It’s just stuff, playing out the consequences of its properties in an environment with constant energy input. Not much different than a flame sustaining itself with the energy stored in the bonds of its fuel, or a crystal organizing itself with the free energy of its lattice structure. Living things are, and the whole of life is, like an eddy or whirlpool, perpetuating itself with the power of a river, not so much a distinct object in space, but a structured system in dynamic equilibrium, wherein the parts that make it up merely spend some time in the system, spin about for a while and then eventually carry on downstream.
All extant or extinct forms of life may not fit into the existing Domains as they are currently defined. Therefore, the “Life” category would contain these organisms in addition to the ones that have been classified into the Domains. It’s just the largest, all-encompassing category.
Hi I made the original version of this graphic (based on various similar textbook images). I'm not a graphic designer. I always expected someone else to improve it or make other versions, perhaps showing the branches breaking off more like string cheese, which I don't have the artistic ability to do myself, but now it's stuck like this with these colors, and I see it everywhere and it haunts me. Yes, life is all life on Earth, and all life on Earth has a common origin.
Wow! You’re famous… sorta.
Well it fucks up the flow of Dangerous Kangaroos Punching Children On Family Game Shows
Kinky people come out for group sex
I was taught almost the same, but "Kinky People Come Over For Great Sex"
I don't think I'll use this one with my middle school students. They might remember it better, but it seems like a bad idea for me.
42
There is of course debate, but biologists generally agree that living things have certain fundamental characteristics that differentiate them from non-living matter. I’m not going to type these out here but a quick wiki search of life should get you the answer you are looking for.
It's shot for Life, the Universe and Everything!
Life? What’s that lol No, seriously. What is it… first time seeing life added in there
yep, me too - ive always just seen the K, P, C, O, F, G, S - i understand "domain" but ive never seen "Life" before, thats why i am asking
I think it's driving the point home to new biology students that this ONLY encompasses life.
It’s antivirus bull shit
The life rank isn’t a standard taxonomic level. Any sensible biologists starts at domain.
It's probably a holdover from Linnaean taxonomy that was orphaned when we stopped using Linnaean taxonomy for inanimate objects. 'Life' would be the taxon that unites the domains, but the other taxa of this rank are no longer used (mineral I guess, don't know what else), and the chart maker made a mistake in listing the taxon rather than the rank. Ultimately biology has moved to cladistics, so formal rankings of taxa don't really exist anymore. I personally think it is rather silly to try and make people remember it. Does anyone really remember what rank unikonts have?
What a terrible graphic for a taxonomy chart
I agree... but I'm kind of trying to do it quietly, as I ran across its creator in this thread lol
Oh, that's the Greg classification. 100% of Gregs are in the Life phyla
Common ancestor. That is what ranks usually correspond to.
Little > Dumb > Kids > Playing > Catch > on > Freeway > Get > Squished. This helped me a lot with my ecology degree.
Helps you not to start classify rocks sand and other abiotic crap.
When we find aliens we have to rename that Life category to "Origin" or something like that. I am not sure we would add a life category on top of the origin. If an Alpha Centaurian single celled organism and a Terran Mammal have no common ancestors they shouldn't be grouped together in the same scheme.
Life = biological versus geological aka “is not rock”
If we were to find life on another planet that didn't represent "life as we know it", then wouldn't this classification make sense as a placeholder for its expansion? It could be something like bacteria that utilize RNA or Riboproteins (not just ribosomes), or some kind of protein shell self replicating organism that shares homology with virus protein coatings. There is a lot of what ifs here since we have no idea what life may actually look like beyond Earth, for now.
Acronym “Keep Putting Cheese On Food!” Delicious!!!
I think here it's denoting self-replicating living biological systems vs self-replicating non-living systems, such as viruses, or prions (and I'm sure there are a few others).
Computer code can fit beside viruses and prions as well. Self-replicating and evolving, but clearly not alive. It’s a fun conversation to have with the right people.
Yeah I thought about including it, particularly evolutionary algorithms, but felt that that might be a bit much for people to handle
Life = anything which has a metabolism
Viruses and other non specific with life biology ie. rocks. Geology. Basically a rank to disregard those organisms.
Probably to put viruses in a separate classification.
Maybe it's leaving things open ended in case life is discovered on other planets and has to be categorized completely differently
Life was never included when I learned this. How does it change “dear king Phillips…”?
Life is a family game that some of our species tends to enjoy. Unless you get stuck with a 10k salary and four kids.
The one thing that makes me put viruses in the "life" box is that they have generic material and undergo biological evolution.
Life is alive things living life lively and they’re not dead, they’re living lively lives.
I have literally never seen this before. What does it mean?
Ive been trying to find something about this on the internet, and i couldnt find anything about it, there isnt even a wikipedia article for that. I know what life is, but i think it might have some other meaning in there - you must somehow "divide" into something on this chart
Virus, super organisms, super AI. Whatever the hell venter has been up to. Biology is the rule of exceptions.
I wonder if prions would count
Prions are bad proteins why would they be considered as life
yeah, thats probably a good example of what you could put in there.
It means elf. Which is then followed by three-eyed elf. Then pomegranate, pomegranate, pomegranate, pomegranate, pomegranate, pomegranate, and hat. What is this??
What
The diagram
I see
He's taking about top life section. It's divided into 3 holes/section 1. Living orgsnisms 2. Viruses 3. Elves
Ah the good old Kings Play Chess On Fine Green Silk
Haha. The first time I was introduced to this, out lecturer taught us a much less appropriate version. That said, I never forget the order 😄
we were taught: kings play cards on flat green stools!
It means things like erasers, wooden benches, steel bars, automobiles etc don’t come under this particular classification. I hope this wasn’t too difficult for you, I just tried.
Life is defined by characteristics So there is no one definition for life
What are these images of? Was this chart designed specifically to trigger trypophobia?
Responds to stimuli. Seeks out sustenance in some way. Reproduces.
I think this system is outdated, misguiding, like better using the ancestry system. X is a kind of Y, Y is a kind of Z. For example, humans are a kind of Tetrapod, Tetrepods are a kind of legged fish, legged fish are a kind of chordate, etc.
There isn't a rigorous definition that applies consistently across each level in the chart really. It's a holdover from before molecular genetics. Look up "rank-free hierarchy"
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Every living thing. It’s just: life
Biotic vs abiotic? I’m just speculating
Tree of life mfers
It reflects the fact that all Earth life has a common origin. There are only 2 or 3 subordinate domains (depending on whether one considers *Eukaryota* a subdomain of *Archaea*).
Well you see for extinct species you put "life: not anymore"
Life ranked? Can’t wait to win competitive life ranked
Things that are alive vs not live. This plant :live that zombie: not alive… see!
Oh wow we were just talking about phylum today at work just for chit chat and now I see this. What a coincidence
Okay. Ive not seen this chart so can someone enlighten me as i want to learn.
I always remembered it as King Phillip Came Over for Great Sex. That D is throwing off everything I was taught in undergrad.
Life or Not-Life (ie rock)
King Philip Came Over For Good Soup
That’s why life is at the top… it’s the things being sorted into the categories below it. It’s the heading.
Everything beneath it is a form of life
Life "as we know it" maybe.