OT: Carbon Dioxide races -> known vs unknown -> terraforming mars -> is or is not

[Erax]

Getting back to the CO2 atmosphere : it could mean any one of a number of things, but these are the more interesting possibilities :

- CO2 with some oxygen; depending on the oxygen level, CO2 'breathers' (who might actually breathe oxygen) and oxygen breathers would have few compatibility problems.
- CO2, nitrogen and other inert gases; both species would need breathers / gas tanks to survive in the other environment. The CO2 species might need an environmental suit (an insectoid species might not need a suit, if it had a resistant, airtight exoskeleton).

[Thermodyne]

CO2 breathers could be carbon cycle just like us. But evolving in a atmosphere with a high concentration of CO2 would have given them the ability to break the CO2 down into CO an O, and then use the oxygen and turn it back into CO or CO2 blowing off the excess carbon in the process. There is some evidence that long term heavy smokers do some of this on a small inefficient scale. Pulling off one of the oxygen molecules and polluting their blood with the CO, which takes a long time to blow off.

[ July 15, 2003, 16:54: Message edited by: Thermodyne ]

[kalthalior]

Interesting link: Exobiology background & theories

[Taera]

The background to my question is the fact that in my current RP my Taeran bugs are creating a close alliance with oxygen-breathers.

Thermodyne: No. Completely no. You're trying to reason with it the normal way. Not all living creatures have to use oxygen - if we cant explain it it doesnt mean it cant be.

Loser: Yep, my bugs didnt have much oxygen there, but they had some - i doubt the mere existance of the gas would cause equipment failure. Still an interesting note to remember.

Erax: Your completely right, unlike humans or mammals in general insectoids do not breathe with their skin - first of all because of the lack of such they have tough natural carpace and have multiple breathing orifices, usually along their thorax or legs.

So considering the exoskeleton is airtight and the only places that receive outside air are treated with a breather, and of course pressure and gravity are in reasonable limits, my bugs should be able to survive on an oxygen or even on a methane atmosphere right?

BTW, regarding Earth not being an Oxygen planet, technically this is true but i think it depends what the planet's flora and fauna uses, plus the atmosphere layers composition (for all i know atmosphere has plenty of H20, 03 and 02 in it) rules that the planet is, after all, an oxygen planet.

[Fyron]

Not all living creatures have to use oxygen - if we cant explain it it doesnt mean it cant be.

The problem is that there are no other substances that can perform all of the roles of oxygen in complex organisms. All organisms on Earth that are more than a simple cell rely on oxygen for all parts of energy generation (not necessarily storage, as for plants, but the molecules they store it in still rely on oxygen). This is because oxygen is a very unique substance that has just the right combination of electronegativity, molecular mass, size, charge, ionization, etc. to work as it does in organisms. Complex alien organisms that do not rely on oxygen could not rely on a single gas; they would have to use several things to fulfill all of the roles of oxygen. And yes, they all need to be fulfilled, because they are too fundamental to be ignored (all relating to energy transmission within the organism and releasing the energy to be used).

[oleg]

I.F., most likely you are correct. In fact I'll not bet a peny against a 1M of pounds that you are wrong. However, there is no much difference between, for example, yeasts and humans - 60% genome similarity ! We know of the extreme habitats of anaerobic bacteria. There is nothing in the laws of physics to prevent the evolution of more complex organisms there too. Yes, it is unlikely, I agree with you, but it is still inside boundares of the serious science.

[Fyron]

Anaerobic respiration (releasing energy from glucose and such without the use of oxygen) is too innefficient for it to work for complex organisms. It can only be used continuously for very simple single celled organisms. It is done in complex organisms such as humans as an extreme backup (such as during very heavy, prolonged excercise), but it is not effective for very long.