Are human red blood cells homo sapiens or a separate organism?

I put some of my blood under my microscope and I thought it’d be cool to upload to iNat. But I don’t know if my red blood cells count as homo sapiens or if red blood cells have their own taxonomy. Like… red blood cells aren’t tiny humans in my body… but they are a part of me… but I myself am not a red blood cell… but the red blood cells aren’t tiny me’s… and if red blood cells have the exact same taxonomy as humans, which are a part of the animal kingdom, does that mean I’m full of animals?
Uploading: IMG_20220709_023725745~2.jpg…

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Blood is a type of connective tissue, its cells are just part of you and not different organisms, your mitochondria were a separate organism at some time, but not now either. You’re a multicellular organism, separate cells aren’t tiny humans (hopefully), not all of them have any DNA at all, but they’re still just cells. You’re full of organisms, but those are not your blood.

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So does this mean my red blood cells are technically homo sapien?

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Sure, id them as so.

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Cool, it’s like 3AM right now though. I’ll do that this morning

So I am full of animals?

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Yeah, symbionts, parasities, bacteria and fungi just hanging around too.

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A red blood cell is as much part of a human as a nose or a leg. If it’s part of an organism, then it is identified as that organism on iNat. For instance, a feather or bone or egg from a blackbird is classified as belonging to the blackbird species.

Your question raises another matter, though: each human is an ecosystem of many many species. We have tiny mites living in our hair follicles, fungi growing on our skin, bacteria in our stomachs, and countless more besides… Indeed, well over half of the cells that make up what we would informally consider as “a human” are actually other species coexisting with us in symbiosis. But blood cells are not another species – our blood cells are a type of human cell, in just the same way as the other cells that make up our skin, lungs, eyes, kidneys, etc.

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I learned in high school bio (way back growing up in Germany) that blood is one of the body’s organs, an unusual one because liquid but still an organ. Not sure if that same definition applies in English. So taking a picture of blood cells is akin to say taking a picture of your liver or kidneys.

Red blood cells in particular are highly specialized and human ones don’t even have their nucleus, mitochrondria or ribosomes any more at maturity, so they don’t carry DNA, cannot divide, have a limited life span and need to be constantly replenished from stem cells making more of them. Because of this, I’m not sure they would even meet the criteria for “tiny animals” inside your body. They’re really just cell fragments at the point they circulate in the blood.

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While there are a lot of organs beyond the traditionally well known heart/liver/kidneys/etc – such as skin, nails and hair follicles – the blood is not generally considered to meet the definition of an organ. The blood vessels (arteries, veins and capillaries) are an organ, but the blood itself is not.

I couldn’t find any evidence that the German scientific community defines organs any differently from this, although it’s certainly possible that in everyday usage the word isn’t used in exactly the same way as in English.

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This is truly an interesting conversation, I wonder, however, will iNat interpret the posting of homo sapien sapien as wild or captive?

iNat marks Homo sapiens automatically as casual (along with cats and dogs)

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Cats and dogs are marked captive only if majority around are captive, humans are made casual, but not marked captive.

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I learned that blood is a tissue, not an organ.
But red blood cells are itself just a part of that tissue…

Noone would consider a red blood cell as a different taxon. It is a cell that makes up an individual organism which is categorized as a particular taxon.

But these are loaded questions–and are at the center of the abortion debate (which we should most definitely NOT get into in this post!).

It’s philosophically challenging to define what constitutes a living being vs. what constitutes a group of living cells (or single cell). Take slime molds for example, which easily transition between single-celled living beings to multicellular living beings. When in the multicellular state, is one of the cells no longer a living being? It was once an independent living single-cellular being before joining up with others. It’s impossible to answer that question. Dictionaries don’t help either. Webster defines being (n) as “a living thing”. But my cells are alive. I’m not made up of dead cells or non-living cells. But we don’t call our cells beings. That’s because the human brain cannot deal with continuums.

So it’s impossible to answer your question without getting into philosophy. You first have to define what you is. If you define yourself as a collection of connected and interacting cells, then no, a single cell is not you (or a human being). But one of your cells is indeed a human cell. Likewise, but even more challenging, is a sperm a human being (in the haploid stage of the human life cycle) or just another human cell? Individual haploid fungi cells are considered living beings so why not sperm? So, these questions cannot be answered without appealing to a definition of what a “being” is–you can define it however you wish–and then everyone in the conversation must either agree to use that definition or walk away.

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iNat observations record organisms or recent evidence of organisms. I’d say human blood is recent evidence of a human.

One book to check out about the human ecosystem is Ed Yong’s I Contain Multitudes.

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“You” is one’s soul, the thing about a human that does not change. Science has proved that every cell in a human’s body has died and been replaced in seven to ten years, except for the neurons in the cerebral cortex. So, in seven years, you have almost none of the same cells as you did when you were born. But you’re still the same person, right? Which is because of your soul, the one thing about you that does not change.

Interesting - it seems this may be a uniquely German thing. E.g. the German Wikipedia page on Blut says: Blut wird als “flüssiges Gewebe”, gelegentlich auch als “flüssiges Organ” bezeichnet. (Translation: Blood is referred to as “liquid tissue” and sometimes “liquid organ”.) I can only find this type of reference to blood as an organ on German language websites, where it does seem to be reasonably common though.

High school has been so long ago for me, I don’t remember what our Biology text said about this, but I’m pretty sure our teacher described blood as a liquid organ. He probably got it from some text. I can find some German medical texts that seem to agree - e.g. a whole chapter on “Blood as an Organ” from the Handbuch der Allgemeinen Pathologie.

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If you want some challenges in thought experiments about this topic (and you are tolerant of the odd expletive), consider reading this piece from Tim Urban back in 2014:
What Makes You You?

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Blood cells are certainly human. Mitochondria, though, are an interesting question - as are the chloroplasts of plants. They’re basically little critters that were once separate, but kind of got imprisoned by the organisms they lived within, and now are “part” of us.

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