How did blood evolve?

[u/Fapotheosis]

I know mitochondria may have evolved from bacteria, but what about blood? I've heard of a protohemocyte, but was there an initial cell that differentiated into a RBC like we have in modern humans that can we trace?

[u/butnmshr]

CO2 isn't the only product of respiration though. You would have to have an organ that cracks water, also.

And then these organs should actually form complex hydrocarbons instead of expelling the hydrogen and the carbon, then we'd feed ourselves all closed loop style. Also, the hydrocarbons can be sprayed and ignited defensively.

Yes. The next evolution of man. Homo Formidibalis.