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FlashbangThroodador t1_jbnsk2v wrote

Depends on your definition of an organism/virus, and what your function of interest is.

For example, if you're simply interested in things that can make more of themselves like viruses do: prions contain no genetic code at all and are simply misfolded proteins that cause other proteins of the same type to misfold into the same conformation.

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jrmxrf t1_jbnxme1 wrote

Yes, even bacteria from u/FrostReaver 's answer is a parasite. Most organisms need something that was made by some other organisms. We divide life into things but because it's easier to analyze it that way, but they both depend on each other and influence each other (the same relationship as within parts of an organism).

So I wonder, is there any organism that if we put on say mars, it could function without any ecosystem? By function I mean not only survive but exponentially reproduce given available resources there. A follow up question would be if it would just deplete the resource it was feeding o and die after that, or could it bootstrap a whole ecosystem (theoretically, after many many millions of years).

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FlashbangThroodador t1_jbnypik wrote

By definition, the only category of organism that meets those criteria are primary producers. This is because even a broth of carbohydrates used to culture an organism would need to be produced through photosynthesis, and so would therefore be requiring something made by another organism or ecosystem.

Rather than relying upon nutrients produced by other organisms, primary producers create their own. The most simple known primary producer are Cyanobacteria, and this phylum of microorganisms are thought to have played a key part in terraforming Earth and produce a huge amount of the oxygen we breathe.

Therefore, based on your parameters, I would say, Cyanobacteria are likely the most simple organisms that are self sufficient and contain minimal code. They would just need nitrogen, phosphorus, water, carbon dioxide and sunlight.

TLDR: all organisms except primary producers are in some way parasitic when you consider that they rely upon the outputs of other organisms within their ecosystem

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jrmxrf t1_jbnzrey wrote

It's always some magic term which once you know there's tons of knowledge to consume, thank you, I didn't know it.

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RGJ587 t1_jbo4jn7 wrote

The issue really comes down to evolution.

The first organisms did not use photosynthesis, but rather chemiosythesis. There is only so simple that you can go if photosynthesis is the only way to produce

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udee79 t1_jbodfzw wrote

The chemosynthesis guys are considered primary producers also. Right?

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throwawaystitches t1_jbomr6c wrote

So there's autotrophs and heterotrophs, which has to do with where you get your carbon (C atoms). If you're an autotroph, you can transform (or "fix") inorganic carbon (like in CO2) to organic carbon, which are molecules that contain hydrocarbons or hydrogen-carbon bonds. Heterotrophs can't do that. They have to consume organic carbon to use it.

This is what determines if you are a primary producer or not. If you are an autotroph, then you are a primary producer. If you are a heterotroph, you must consume other organisms to get your carbon and are a consumer (note that there are primary consumers, who consume primary producers).

Then there's where you get your energy. If its chemicals, then you're a chemotroph. If its light, then you're a phototroph. If its both, congrats, you're a mixotroph.

You can mix these up. You can be a photoautotroph that gets your energy from the sun and fixes carbon. Cool, you're probably a plant or cyanobacteria. You could also be a chemoheterotroph that must consume your carbon and obtains energy from the chemicals you consume. Dang, you're probably a human.

Chemosynthesis and photosynthesis refer to autotrophic processes so they are primary producers. But the reason isn't because they utilize chemicals to get energy, its because they fix carbon in the process.

Sorry for writing this all out. I'm trying to procrastinate. Thank you for your help.

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