Let's create an alien biosphere!

[Schiaparelliorbust]

Yes. For example, the organisms should still be to use transition metals inside to form coordination complexes.

So should we create the first multicellular organisms now (or something related like initial partial coordination) or something else?

[MathAndCode]

So should we create the first multicellular organisms now (or something related like initial partial coordination) or something else?

We should figure out how biochemistry will respond to the increased levels of oxygen first.

[Schiaparelliorbust]

We should figure out how biochemistry will respond to the increased levels of oxygen first.

A few compounds will not be nearly as abundant, so many clades using them could either go extinct or be forced to start using newer compounds.

[MathAndCode]

A few compounds will not be nearly as abundant, so many clades using them could either go extinct or be forced to start using newer compounds.

Yes, but they could also evolve to make those compounds themselves. However, this requires energy, so organisms that aren't next to a hydrothermal vent will be forced to either evolve photosynthesis or get nutrients from other organisms.

[Schiaparelliorbust]

Yes, but they could also evolve to make those compounds themselves. However, this requires energy, so organisms that aren't next to a hydrothermal vent will be forced to either evolve photosynthesis or get nutrients from other organisms.

Perhaps when they're trying to eat each other they evolve endosymbiosis with the photosynthetic partner becoming a new organelle, like on Earth.

[MathAndCode]

Perhaps when they're trying to eat each other they evolve endosymbiosis with the photosynthetic partner becoming a new organelle, like on Earth.

That's possible, but I don't think that it's likely because a predator unable to digest its prey would not survive, and a predator able to digest its prey would kill the engulfed organisms.

[Schiaparelliorbust]

That's possible, but I don't think that it's likely because a predator unable to digest its prey would not survive, and a predator able to digest its prey would kill the engulfed organisms.

What do you suggest would happen in response to the increased oxygen levels then?

[MathAndCode]

What do you suggest would happen in response to the increased oxygen levels then?

There are sulfate-reducing organisms near the hydrothermal vents that use an electron transport chain. It could be adapted to use oxygen as the final electron acceptor.

[Schiaparelliorbust]

There are sulfate-reducing organisms near the hydrothermal vents that use an electron transport chain. It could be adapted to use oxygen as the final electron acceptor.

What would that cause? Also, photosynthesizers will definitely switch to entirely using CO₂.

[MathAndCode]

What would that cause?

It would allow them to get energy using dioxygen.

What would that cause? Also, photosynthesizers will definitely switch to entirely using CO₂.

Yes, but that won't happen until carbon monoxide has been depleted.

[Schiaparelliorbust]

Yes, but that won't happen until carbon monoxide has been depleted.

Hasn't that already happened (or will happen relatively quickly)?

[MathAndCode]

Hasn't that already happened (or will happen relatively quickly)?

I don't think that there should be a gap of at least 100 million years where nothing happens, and we haven't discussed what will happen after photosynthesis arises but before carbon monoxide has been completely depleted.

[Schiaparelliorbust]

I don't think that there should be a gap of at least 100 million years where nothing happens, and we haven't discussed what will happen after photosynthesis arises but before carbon monoxide has been completely depleted.

Is that how long it takes for CO to get depleted? Also, what do you propose happens during that period?

[MathAndCode]

Is that how long it takes for CO to get depleted? Also, what do you propose happens during that period?

It will take at least that long for carbon monoxide to be depleted. It will likely take longer, but I haven't figured out the exact value yet.

[Schiaparelliorbust]

It will take at least that long for carbon monoxide to be depleted. It will likely take longer, but I haven't figured out the exact value yet.

May I ask you where you got that value?

[MathAndCode]

May I ask you where you got that value?

I took a rough estimate of the minimum fraction of the early atmosphere that is or would be depleted before carbon monoxide, then I multiplied it by the estimated length of the atmospheric change.

[Schiaparelliorbust]

I took a rough estimate of the minimum fraction of the early atmosphere that is or would be depleted before carbon monoxide, then I multiplied it by the estimated length of the atmospheric change.

Good. In the time it takes carbon monoxide to deplete, clades that can use (also) use carbon monoxide for photosynthesis will diversify, ag least relative to the ones that can't. Will using CO₂ cause any other changes (such as being more energy efficient)?

[MathAndCode]

Good. In the time it takes carbon monoxide to deplete, clades that can use (also) use carbon monoxide for photosynthesis will diversify, ag least relative to the ones that can't. Will using CO₂ cause any other changes (such as being more energy efficient)?

Didn't the photosynthetic organisms evolve to use carbon monoxide before carbon dioxide?

[Schiaparelliorbust]

Didn't the photosynthetic organisms evolve to use carbon monoxide before carbon dioxide?

Yes, they did, but I think that some clades will start using CO₂, especially due to decreasing CO levels.

[MathAndCode]

Yes, they did, but I think that some clades will start using CO₂, especially due to decreasing CO levels.

Yes, and those clades will likely be more successful, especially once the oxygen starts to deplete carbon monoxide.

[Schiaparelliorbust]

Yes, and those clades will likely be more successful, especially once the oxygen starts to deplete carbon monoxide.

What else might happen?

[MathAndCode]

What else might happen?

The organisms that adapt their electron transport chain to accept oxygen as well as sulfate will likely be the ancestors of the first successful heterotrophs.

[Schiaparelliorbust]

The organisms that adapt their electron transport chain to accept oxygen as well as sulfate will likely be the ancestors of the first successful heterotrophs.

They weren't successful before? Also, do we even have any heterotrophs at all?

[MathAndCode]

They weren't successful before? Also, do we even have any heterotrophs at all?

There haven't been any widespread heterotrophs so far. I'm using widespread as a requirement for counting as successful.

[Schiaparelliorbust]

There haven't been any widespread heterotrophs so far. I'm using widespread as a requirement for counting as successful.

Do you think we need some sort of chemical infrastructure for the digestion of other organisms?