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I am currently attempting to construct my alien planet with exotic forms of life that use alternative metabolisms.

I got an idea that I could perhaps somehow replace the photon energy required in photosynthesis with something else that could help oxidize H2O to separate it into hydrogen and oxygen to then react with carbon dioxide to create glucose.

I had already imagined an organism that lived in an environment abundant with magnetite that could generate electricity through using specialized organs. I imagined that it would absorb magnetite as a part of its diet and the body would divide it into small fragments that would be transported to a special organ filled with small coils and spin around to generate electricity just like a generator.

So my question is: Can electricity be used as a substitute for light in photosynthesis? I am unsure how the process would work but if I am not mistaken electricity can help excite other electrons in atoms and could help oxidize water. However I have a gut feeling there is a massive blunder in my assumptions somewhere. Any information on the topic is appreciated.

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So, on a principle level your idea has no blunder. It should technically be possible for such an organism to evolve. However, there are multiple issues which i think render this almost impossible.

1. Mechanics

You mention the organism would absorb magnetite and use that to build a primitive magnetic generator. On its surface, this seems like a feasible idea. However, issues start arising very quickly.

For a start, how did the life evolve to this complexity for it to be able to make such a generator ? As in, you cant really make such a complex biochemical machine out of primordial soup.

enter image description here

Right, the Motor Proteins in your body were not one of the first evolutionary steps. In the grand scheme of things, deliberately moving biochemical machines are really hard to do. While a rotating bit and a coil might seem easy, (And i might be wrong here) but i do not think there is any biochemical machine in your body that has freely rotating parts in it. So just from that angle, if i am not mistaken, evolving such a Generator is a huge task.

Then there is the question, like what powers the generator ? Remember, someone has to turn the shaft in order for Electricity to be made. So what mechanism turns the shaft ? Where does the energy for that come from ? And i dont mean in a "Hey is there another Protein that swings the shaft". But rather, at the root of this process where does the Creature get the energy needed from ? Because it better not be Photosynthesis.

2. Roots and Boots

When you take a look at Earth, you might notice there is a lot of Green stuff around. While there is noticeably less moving stuff around. Right there are a lot more trees than animals (In terms of Biomass). The reason for this is very simple.

enter image description here

On average, every m² of ground on Earth gets 1300 Watt of solar energy. It is this energy which is driving Earths ecology. Look at any, literally any, biological process and look at where each part gets its energy from. At the root of every Energy exchange chain is the Sun. (Human Eats Cow, Cow eats Grass, Grass eats light, light -> Sun). There are some exceptions like cringe creatures on Hydrothermal vents. But even then, you can argue the Sun and Earths core do kind of provide the same thing. What is heat, if not less spicy photons ?

And this is really your issue. Replacing photosynthesis is a very hard ask. Sunlight is virtually everywhere and the evolutionary path to using it does not appear to be super hard. In fact, Algae was probably one of the first lifeforms on Earth.

As i said before, your basic though process is not incorrect. But you fail to see what evolutionary is just going to be easier to do. And even if you can make it work by for example not having Sunlight, where does the energy to drive life no come from ?

Magnets ?

The only real answer i can see to the question i posed is, like a Neutron star or something. But at that point we would be taking about such an unstable world any life evolving would be a mirical. Let alone something this complex.

Conclusion

I dont think what you propose here is really feasible. Not because the core mechanical idea is incorrect. it isnt. But because the path to evolving something like this would be so endlessly complex and filled with better alternatives that it is just hard to see work.

And even if you can evolve it, where does the Energy come from ? In a sense, what you have done here is kick the Can down the road.

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    $\begingroup$ Thank you so much for this answer you've given me so many ideas and possible workarounds to research! $\endgroup$
    – Venik Hue
    Commented Jul 13, 2023 at 17:03
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    $\begingroup$ Thanks ! Though always at least wait a day so other people can answer as well. As for research, i would advice looking at Hydrothermal vents and life in regions with minimal or no sun light. I.e the arctic circle. You will note btw, there are not a lot of plants there. $\endgroup$
    – ErikHall
    Commented Jul 13, 2023 at 17:08
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    $\begingroup$ Heat isn't less spicy photons, organisms on hydrothermal vents don't live off the heat there (at least not exclusively, they may depend on it for heating, but they metabolize H2S), and photosynthesis also requires complex-to-evolve machinery. $\endgroup$
    – Caesar
    Commented Jul 14, 2023 at 1:34
  • $\begingroup$ @Caesar well yes, thats the point. The ecosystems around hydrothermal vents strongly depend on the heat. But most of the organisms dont literally absorb it. Same with how humans depend on the Sun even if we dont eat it $\endgroup$
    – ErikHall
    Commented Jul 14, 2023 at 9:02
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    $\begingroup$ Just as a nitpick - flagella rotors and atp synthase are both examples of biological things that spin on an axis, like a generator. The functioning isn't perfectly analogous, but it's pretty possible for these things to evolve $\endgroup$
    – lupe
    Commented Jul 14, 2023 at 16:05
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Electricity is not a source of energy, but just a carrier, in the same way a bucket of water just carries water, while a well sources it.

You say it also in your description:

it would absorb magnetite as a part of its diet and the body would divide it into small fragments that would be transported to a special organ filled with small coils and spin around to generate electricity

What's the point of spending energy to spin the coils which then produce energy for your organism? It can make sense only if the cause of the motion is external (like a very frequent wind or rain which would move the equivalent of the leaves of this organism) but then adding the intermediate step of going through electricity to excite other atoms would just introduce another loss in the chain, leading to what I suspect would be a quick strike out from natural selection.

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Your ideas concerning a nanoscale molecular motors based on macro scale electric motors are interesting. I’m not sure how feasible they would be, the possibilities of chemistry are almost endless so who knows, but other mechanisms already exist that would be much easier to use.

The biggest issue you have is a source of power. You might want to use a proton gradient as a source of that power as that is actually used by some organisms in the absence of light to create energy.

There are no macroscopic wheel structures in nature, however there are some microscopic ones. One example is the bacterial flagellum motor powered by ATP (Adenosine Triphosphate): https://www.nature.com/articles/s41467-021-24715-3 This was worked out in painstaking detail to refute claims by supporters of Intelligent Design who claimed it was an example of irreducible complexity (which it is not).

Another is the proton pump that is found widely in living cells generating ATP https://i.ytimg.com/vi/vIs8DOG5mZc/maxresdefault.jpg

It’s used in photosynthesis, but the process is believed to be much more ancient than that. A good case has recently been made by biochemist Nick Lane that life itself may have originated around alkaline deep sea vents (not black smokers) using proton gradients as a source of power. https://www.nature.com/articles/nature.2012.12109 https://www.nature.com/articles/nature10325

Once you have ATP the biochemical world is your oyster as it is the main energy currency of cells. No need for photosynthesis. https://phys.org/news/2015-04-vital-life.pdf

Have a look around the link below using the arrow keys at the bottom right of the screen. There are almost 200 reactions involving ATP (ATP synthase can be found on page 2). http://biochemical-pathways.com/#/map/1 As you will understand it is probably unnecessary to dive too deep down that rabbit hole if it is a work of fiction.

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imagined that it would absorb magnetite as a part of its diet and the body would divide it into small fragments that would be transported to a special organ filled with small coils and spin around to generate electricity just like a generator

You have a perpetual motion machine problem. Magnetite is not energy. Magnetite is just magnets. You need an actual source of energy (such as regular food or sunlight) to spin the motors the same way we burn fossil fuels to turn the generator (which for the purposes of your question let's say they are made with magnets).

The photosynthesis equivalent of electricity would be using raw electrical currents or changing magnetic fields that already exist in the environment. Those are sources of energy and can be harnessed if you can think up of an environment for them. For example:

  1. A world FILLED with lightning. This doesn't seem to be reliable enough to work with though.
  2. Geologic features that basically form a massive giant galvanic cell that results in low levels of current flowing through a body of water. This is probably the most straightforward and believable.
  3. Constant tectonic activity in the form of tremors could perhaps provide relative motion for the magnetite. But perhaps having the crust full of piezo materials would be best so that electric currents flow in the ground. The continuous tremors might might strain belief though.
  4. A river that is constantly eroding a very large magnetite mountain causing sufficient amounts of magnetite debris to be moving with the water. This might strain belief since it seems like it would need to be a lot of debris over a very long period of time mountains only have so much material.
  5. Plant like organisms that sway in the wind or water and grow around magnetite, and use their relative motion with the magnetite to produce electricity. Provides some of the more interesting possibilities and doesn't seem too outlandish.
  6. Plants could having piezo electric capabilities such that deformation from swaying in wind or water produce electric currents.
  7. Plant like organisms that sway in the wind or water that just happen to concentrate magnetite in the soil for whatever reason, and other symbiotic (or perhaps parasitic) organisms use that swaying magnetite to produce electricity. Provides some of the more interesting possibilities and doesn't seem too outlandish.
  8. Tidal forces as per @Caesar's suggestion could work. The movement happens less frequently and more slowly than would be preferred but can be relied on to continue happening for a very long period of time. It might be best not to rely on the relative motion of magnetite and conductor in this case since the movement is so unlocalized which means organisms might need to span very large swaths of land to make use of it (like interconnected moss or algae). Perhaps a better approach is to have the crust be full of piezo materials such that they generate electric currents in the ground throughout the day.
  9. Harsh waves constantly beating against cliffs or beach rocks made of piezo materials could produce electric currents in those cliffs which could be harvested.
  10. The very slowly but continuous movement along fault lines might work with piezo energy to produce energy there.
  11. Electric currents can be produced by thermocouple junctions of two different metals exposed to a temperature gradient so you could think up of something like a vein of such materials running between a volcano or geothermal and cool ocean water.
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  • $\begingroup$ 7. Tidal forces? $\endgroup$
    – Caesar
    Commented Jul 14, 2023 at 1:37
  • $\begingroup$ @Caesar That could work. I added some thoughts about that and thinking about it gave an idea about piezo electricity that could replace magnetite in some instances. $\endgroup$
    – DKNguyen
    Commented Jul 14, 2023 at 2:31
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Real Power

As DKNguyen notes, electricity is not in and of itself, an energy source, but rather the manifestation of moving charges due to some other energy imbalance (the true energy source). You mention magnetite, and that may play a role in what you seek.

Jupiter has a mantle of metallic hydrogen. The hydrogen is so densely packed it forms a solid, and a conductor at that. This is mainly responsible for its massive magnetosphere, the strongest in the solar system. If creatures lived on a planet with such a strong magnetic field, then ferromagnetic fragments inside their bodies could act like inductive coils, harnessing electricity.

Electric Eaters

We already know of bacteria that consume electric charges for their metabolism. So you wouldn't even be inventing a wholly new thing.

Now, the problem here is that having a strong magnetic field is not sufficient to generate electricity. There needs to be movement of or through the field. So you can either say that your planet's magnetic field precesses at a very high rate (quite unusual and requires moderate-high levels of handwavium), or you could say that your organisms move through the field quickly. If your planet has a dense atmosphere, bacteria could fly through it in long-lived storms such as on Jupiter, and this motion could itself drive the internal biological dynamo. However, any creatures left static on the ground would be out of luck. You could also have strong tectonic activity with large mountains and numerous rivers. The rivers could be quite fast and provide the necessary motion for creatures floating in them. Or the ocean currents could also do the same.

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  • $\begingroup$ "4. A river that is constantly eroding a very large magnetite mountain causing sufficient amounts of magnetite debris to be moving with the water." ... and that's the end of the story; there's no climbing out of the water. "construct my alien planet with exotic forms of life" that are utterly uninteresting and will never develop civilization? No problem. $\endgroup$
    – Mazura
    Commented Jul 15, 2023 at 14:37
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No need for rotors

There's no need to build a complicated electric motor to harness electricity. Photosynthesis already uses energized electron transfer in a few stages, from memory. Hook into those, and you're set, skipping out the light conversion steps altogether.

In addition, if you applied an electric charge to one side of a membrane, with an atp synthase protein poking through, you could simply drive atp production with electricity. Making one of the sides negativity charged would provide a motive force for positively charged H+ ions to cross the membrane, driving the atp pump. From there, your biochemistry is the same as everything else. The difficulty is storing or moving the charge.

I'd propose conductive wires and an insulated outer coat are the sole requirement of an electrically powered organism. You need some way for the charge inside a membrane to be different from the charge outside a membrane, but, do that, and you're set.

Incidentally , electric eels generate intense electric currents, using only molecular pumps, so running a bunch of this system in reverse would net you an electric powered creature.

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As others pointed out electricity is a mean to transport energy and you need some way to produce it in the first place, THEN you can "easily" use it to produce something having the same role of ATP.

You have essentially two ways to produce electricity in a body:

  • chemical reaction (i.e.: the good old Volta way. get two different metals and put a ion-heavy solution in between or, better invent a "fuel cell"), but there you need to devise some "real source of energy"; ALL biological (and not only) energy on Earth is "Sun power" either direct or "stored" somehow.
  • mechanical: attach magnetite (or something similar) to some taut filaments in a fluid flow (fluid flow is real source of energy, most likely Sun-power all the same); filaments would start to vibrate (frequency depending on tautness) and thus magnetite would induce current on nearby objects, including ATP-producers (you could even go "wireless").
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