anyone interested in more abstract mathematical models related to this question can consult, e.g., this page

https://www.moshesipper.com/the-artificial-self-replication-page.html

and this wiki shows the efforts of a community to find small self-replicating and other interesting patterns in Conway's Game of Life

https://conwaylife.com/wiki/

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"Specific" was, at least originally, a generic term to indicate that the parameter being discussed has been normalized by some relevant unit to turn it from an extensive property to an intensive property. Occasionally in the context of specific heat, you will actually see people write out "mass specific heat" or "volumetric specific heat" or "molar specific heat".

People working in a particular context almost certainly just use the term specific heat to refer to whichever specific intensive property is most often relevant, so it doesn't surprise me to hear that some people use it to mean molar specific heat rather than mass specific heat.

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It seems that you are referring to hepatitis D, a very interesting virus. It’s the smallest known virus to infect humans and it’s genome only codes for one protein, HDAg (hepatitis D antigen) which can be produced in two sizes. In order to replicate it needs not only the human cell but there must also be a co-infection with hepatitis B since hepatitis D “steals” the surface antigen (HBsAg) from hepatitis B so that both viruses have identical viral membranes.

From the other discussion in this thread I see a lot of argument whether viruses are alive or not. This is not particularly interesting to any person infected with hepatitis D (and B simultaneously) since it behaves in very “alive” manner and seriously impacts the life of the infected.

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> I've got some pretty interesting animal facts for the Y chromosome.

Let's hear them!

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Everything alive is dependent on something else in their environment to stay alive. If you define life by function instead of properties you can arrive at a different conclusion.

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There are no easy dividers like these to separate life from non-life. The short answer is that it depends on how you define life. Others define it in another way and include viruses among live organisms. Just like there is no clear definition on what a game is.

Off topic, but I really appreciate when people like you who seem to know what they’re talking about share some insights that laymen like myself can understand. Just makes me want to read up on things

There exist self-replicating strands of RNA. All they are is RNA in solution that can gather and assemble loose nucleotides into copies of itself.

But if a virus is alive, then they could probably be considered alive too.

Keep in mind it lacks a lot of defensive mutations

If the wrong mutations from this cell however occured elsewhere either by exposure or naturally replicated similar genes that'd certainly be concerning

Viruses don't have a metabolism. Generally speaking, using energy is part of being alive. Also, a virus doesn't replicate its own DNA. It co-opts the replication mechanisms of a host cell and forces the cell to do the replication.

In my opinion, that's enough, but the taxonomists of the world disagree.

There are so many organisms that are obligated to have a host to survive. Granted, they mostly need one condition or another that the host provides, rather than invading its cells, but I much find the distinction between virus and obligate pathogen to be just one that is being held onto rather than one that is meaningful. I'm open to someone giving me a real definition, though I've never encountered one I feel satisfying.

Worth noting, my opinion on the lack of consensus for species is that there genuinely can't be one. Humans try to classify biology, but biology doesn't care. You can look at the clostridium or clostridioides clades or the bacillus cereus groups and see examples of biology laughing at us trying to name a species when there is so much intermingling and genetic transfer or so little genetic difference between "species". Dengue virus subtypes might be even clearer, though that's an example of what should arguably be four species being lumped into a single one. Also, why would a non living entity be granted living entity taxonomy like "species" or "genius"? I think that's a matter of convenience, but it does raise an eyebrow because viruses have evolutionary histories as rich as bacteria or animals.

Then there's the "there's no such thing as a tree" argument, that I personally subscribe to.

Long story short, between understood "convention", attempts at classification (taxonomy) that can only approach but never reach the truth, the complicated phylogenetic nature of the world - the fuzzy line between the same and different, and the general resistance to change, I don't think there's really a clear answer for what constitutes an organism and why. Again, I'm open for debate or education.

I've heard some think it's best to define an infected cell as the living virus, treating virions as reproductive material. I don't know how widespread this idea is, but I thought it was an elegant way to define them as living.

If you're counting viruses as an "organism", which the biological community does not, then the minimum amount of code required is none. Prions are misfolded proteins that have no DNA/RNA whatsoever and are able to "function" in much the same way as a virus by causing other proteins to misfold.

Yeah, that’s why I used quotes for organism. I consider them closer to nano-robots than a cell. But they still use DNA

There's not really any single paper about it, so much as it being one of the most commonly held beliefs among biologists looking at how life might originate.

There are a lot of variations to the idea too though: some might argue that DNA came first, while others suggest that life actually started with proteins, and DNA/RNA came later. So far as I understand, the protein theory is most widely supported, and is partly why scientists get excited when they find amino acids somewhere.

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The Y chromosome is unable to perform recombination so most damage is unable to be repaired. This causes loss of genetic information overtime, if the genes were critical to life the animal would be unable to reproduce. So only genetic losses that are no/low negatively impactful can be passed on.

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