Atmospheres

[Captain Kwok]

Slick:

Don't let Fyron rile you. I've enjoyed your responses thus far!

Less complex organisms like bacteria require far less energy per cell for metabolic purposes than an Eukaryotic cell like ours. This is why they can use less energetic metabolisms based on different compounds. Even so, most of them can only survive because they have no competition for resources because of their extreme environments like thermal vents, etc.

However, I suppose if you lived on a planet where say NH4+ was in high enough concentration, you might see some higher creatures (on the order of nematodes or porifera) that could use NH4+ for respiration.

Another possibility is getting H2 breathers in a hydrogen Gas Giant or something like that. H2 is similiar to O2 on the energy scale and might be able to support some kind of creatures, kind of like the Abbidon.

However, I'm pretty sure there is life out there, and not just microbial, but complex lifeforms like us!