Basically, my question is: which living structures does the biological taxonomy apply to? For example, do individual wolf cells have the same species status as the whole multicellular wolf? Is it appropriate to say that an individual wolf neuron is a Canis lupus? What about its sperm or egg cell? And how about its subcellular structures (is an individual wolf protein a Canis lupus)?

P.S. Does anyone know any books or articles that deal with this issue in detail (the applicability of taxonomy, or whatever it's called).


2 Answers 2


To answer this kind of questions one has to understand Concept of Identity.

Parts Get Identity Of The Whole

Same problem, at its heart, arise in Ship of Theseus. If you replace parts with new parts till you have replaced all the parts of the ship, is it still the Ship of Theseus?

The answer is: yes, its still the Ship of Theseus. All the pieces as long as they are part of the ship have identity of the ship. They get that identity, and loose their independent identity, as soon as they become part of the ship.

The answer to the wolf question is also: yes, individual cells of a wolf, as long as they are part of the wolf, have the identity of the wolf.

The operating word here is "part of". Once the cells are removed from the wolf their identity is changed. They become independent.


If I hit any part of a wolf then I am hitting the wolf. It don't matter which part I hit. It also don't matter that the part is new or old. I am hitting the wolf.


Hitting head of wolf is hitting the wolf, hitting its feet is also hitting the wolf, hitting its tail is also hitting the wolf. That much is clear to everybody.

Now consider soil that is 100 miles away from wolf, and air that is 1000 miles away from there. If I hit the soil have I hit the wolf? If I swallow the air have I swallowed the wolf?

Nobody will say I have. Its very clear that the soil and the air are not parts of the wolf. The wolf has nothing to do with them. It is very, very far away from them and never encountered them.

Now, the wolf moved to the area where the soil is. The soil is not converted into grass, as do the air that used to be away from the soil. The wolf now ate the grass. Some of the grass become part of body of the wolf.

I hit that part of body, do I hit the wolf? Its already established that hitting any part of wolf is hitting the wolf. So, yes, I have hit the wolf. It also means that I have hit the stuff that used to be soil and the air.

Something happened when the wolf ate the grass. That something is, the soil and the air now became part of the wolf. The soil and the air changed their identity. Lets consider the reverse of the above operation. After a few weeks the proteins in body of wolf got shredded in waste products (urine etc) from the wolf. They are no longer part of wolf. If I hit them am I hitting the wolf?

I cannot be hitting the wolf same way as I cannot be hitting the wolf when I hit the soil 100 miles away from the wolf long before the wolf ate the plants that grow from the soil.

Its a logical necessity. If an operation takes you from point X to Y then a reverse operation must have took you back from Y to X. It has to if its a reverse operation of the first operation.

If hitting the soil which will grow plants which will be eaten by wolf, is not hitting the wolf; then hitting shredded stuff from wolf is by necessity not hitting the wolf.

  • In me humble opinion, whether something, an x (protein/cell/gamete/etc.) belongs to a particular species, in this case Canis lupus would depend on whether x is identifiable as Canis lupus.
    – Hudjefa
    Commented Jan 5, 2023 at 10:55

I don't know of a specific book on taxonomy that deals with this, but I would argue from the concept of emergence.

We can assume that everything around us is made of the same constituent fundamental parts (standard atoms made of protons, neutrons, and electrons for the sake of simplicity).

A wolf is made of these atoms, just like a human is. Even though they are both made of the same fundamental building blocks, we regard them as different entities because the atoms are arranged differently in a human vs a wolf. Of course, even between two monozygotic twin wolves, their atoms are arranged differently, yet we would still think of them as "identical."

This is due to the concept of emergence. A "wolf" as taxonomy defines one, is a concept humans invented and refined. Before genetic science, we mostly divided animals based on their physical characteristics. If the specific characteristics of an animal's teeth, for example, was one criteria used to distinguish a wolf from a domestic Labrador, it would be correct to say that the teeth (as a whole) are "wolf teeth."

Using this example, you can see that we've gone from taking the animal as a whole (the "wolf") and drilled down a bit into specific distinguishing characteristics (teeth) and we have enough information to define teeth with specific characteristics as "wolf teeth."

With molecular science, we can go even further, and do the same regarding specific cells. Without genetic science, we might look at wolf fur and Husky fur and decide that we can't tell the difference, so it becomes less specific "canine fur." But with genetic science, we might look at the same fur and realize that wolf fur has wolf-specific DNA, allowing us to define it as "wolf fur" again.

Taking these examples and generalizing a bit, you can see that the way we define a wolf, or things that make up the wolf, essentially depends entirely on how much information we have regarding the wolf. Without molecular science, we can only define species based on their physical/behavioral characteristics. If we add molecular and DNA science, we can define deeper constituent molecular structures as wolf, because now we can differentiate between things such as "wolf cells" and "Labrador cells".

But, if we go all the way down to atoms, it's currently impossible to differentiate a wolf from a Labrador or even a table. These entities are made of the same thing, but we don't have atomic blueprints for wolves, Labradors, or tables. Therefore, you couldn't say that certain atoms are "wolf atoms" and others are "table atoms." To us, there’s no meaningful difference between either set of atoms.

Using this logic, we can see that wolves are emergent concepts. They are not fundamental parts of the universe, yet they exist, and they are constructed of the same fundamental parts of the universe that tables are. At some point in the hierarchy of existence, going from subatomic particles, to atoms, to molecules, to cells, to structures, to beings, to species, to concepts: we are able to determine where tables and wolves split into separate branches of existence. The more information we have, the further down (closer to the base building blocks of the universe) we are able to determine the split.

A wolf (or any part of it) can only be called “wolf” as long as we can distinguish is from anything else.

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