Let's create an alien biosphere!

[MathAndCode]

Yeah, up until the Avalon explosion that led to the Ediacaran biota there wasn't much change. There were only simpler multicellular organisms like cnidarians and sponges and unicellular ones.
Edit: The timeline is asking for a start and end date in the form of DD/MM/YYYY. What should I do?

You don't need to use that particular site in order to make a timeline. If you want, you can set Year 0 (or rather, Year 1) to be the planet's formation and pretend that the planet has the same year length as Earth.

[Schiaparelliorbust]

You don't need to use that particular site in order to make a timeline. If you want, you can set Year 0 (or rather, Year 1) to be the planet's formation and pretend that the planet has the same year length as Earth.

I could either make every year equal to a million years or I could just add the timeline to my user page.

[MathAndCode]

I could either make every year equal to a million years or I could just add the timeline to my user page.

I frankly don't think that having a perfectly formatted timeline is very important.

[Schiaparelliorbust]

I frankly don't think that having a perfectly formatted timeline is very important.

User page it is then.

[Schiaparelliorbust]

Can we make the first multicellular organisms now?

[MathAndCode]

Can we make the first multicellular organisms now?

Should we add anything else to the timeline first? My list was not intended to be complete.

[Schiaparelliorbust]

Should we add anything else to the timeline first? My list was not intended to be complete.

Yes. Sorry. We can make the glycerol photosynthesizers.

[MathAndCode]

Yes. Sorry. We can make the glycerol photosynthesizers.

Besides the simple energy-making reactions, do we need to worry about the exact compounds and reactions?

[Schiaparelliorbust]

Besides the simple energy-making reactions, do we need to worry about the exact compounds and reactions?

What other reactions might there be?

[MathAndCode]

What other reactions might there be?

Plants use a different intermediate.

[Schiaparelliorbust]

Plants use a different intermediate.

I thought you meant reactions not having to do with energy like growth or defense.

[MathAndCode]

I thought you meant reactions not having to do with energy like growth or defense.

I meant that we should decide on the base reaction, but we don't have to figure all of the intermediate steps.

[Schiaparelliorbust]

I meant that we should decide on the base reaction, but we don't have to figure all of the intermediate steps.

Oh ok. I don't think it's absolutely necessary. but it might help. What do you think?

[MathAndCode]

Oh ok. I don't think it's absolutely necessary. but it might help. What do you think?

I would prefer to not spend time on that (mainly because I know that I would be plagued by indecision), but I will do so if you wish.

[Schiaparelliorbust]

I would prefer to not spend time on that (mainly because I know that I would be plagued by indecision), but I will do so if you wish.

No, you don't need to. You're right, it would take some time to do it.

So is the next step glycerol photosynthesizers or something else?

[MathAndCode]

So is the next step glycerol photosynthesizers or something else?

We should decide how quickly the atmosphere will change. When carbon monoxide gets depleted, that will likely drive the photosynthesizers to gain the ability to use carbon dioxide instead.

[Schiaparelliorbust]

We should decide how quickly the atmosphere will change. When carbon monoxide gets depleted, that will likely drive the photosynthesizers to gain the ability to use carbon dioxide instead.

That's obvious. Would it cause any important changes?

[MathAndCode]

That's obvious. Would it cause any important changes?

It would likely make multiple reactions that the organisms currently use to create energy unfeasible.

[Schiaparelliorbust]

It would likely make multiple reactions that the organisms currently use to create energy unfeasible.

We have these two reactions that use CO:
CO+H₂O→CO₂+H₂
3CO+4H₂O→C₃H₈O₃+2O₂

[MathAndCode]

We have these two reactions that use CO:
CO+H₂O→CO₂+H₂
3CO+4H₂O→C₃H₈O₃+2O₂

Like I said before, the organisms will have to evolve a way to start with carbon dioxide for the second reaction instead of carbon monoxide. I suppose that they'll have to simply drop the first reaction.

[Schiaparelliorbust]

Like I said before, the organisms will have to evolve a way to start with carbon dioxide for the second reaction instead of carbon monoxide. I suppose that they'll have to simply drop the first reaction.

Other than that is there anything? Also, I already said that 3CO+4H₂O→C₃H₈O₃+2O₂ would become 6CO₂+8H₂O→2C₃H₈O₃+7O₂.

[MathAndCode]

Other than that is there anything? Also, I already said that 3CO+4H₂O→C₃H₈O₃+2O₂ would become 6CO₂+8H₂O→2C₃H₈O₃+7O₂.

What I think is more likely is that photosynthetic organisms will gain the ability to use either carbon dioxide or carbon monoxide, at least for a while. In the Calvin cycle, using carbon monoxide instead of carbon dioxide would theoretically allow the plant to convert one molecule of ribulose 1,5-biphosphate into one molecule of 3-phosphoglycerate and one molecule of glyceraldehyde 3-phosphate without having to expend a molecule of ATP or a molecule of NADPH (although it would have to use a different enzyme). The organisms on the alien planet might do something similar, although they may eventually lose the ability to use carbon monoxide.

[Schiaparelliorbust]

What I think is more likely is that photosynthetic organisms will gain the ability to use either carbon dioxide or carbon monoxide, at least for a while. In the Calvin cycle, using carbon monoxide instead of carbon dioxide would theoretically allow the plant to convert one molecule of ribulose 1,5-biphosphate into one molecule of 3-phosphoglycerate and one molecule of glyceraldehyde 3-phosphate without having to expend a molecule of ATP or a molecule of NADPH (although it would have to use a different enzyme).

So what's your point? (I don't understand much of this unfortunately.)

The organisms on the alien planet might do something similar, although they may eventually lose the ability to use carbon monoxide.

It would probably become a vestigial trait and disappear at some point.

[MathAndCode]

So what's your point? (I don't understand much of this unfortunately.)

It's possible to be able to use either carbon dioxide or carbon monoxide as a source of carbon for the same pathway.

[Schiaparelliorbust]

It's possible to be able to use either carbon dioxide or carbon monoxide as a source of carbon for the same pathway.

Would you like that to happen?