Re: heavy metal !!!!!

Beth.Fulton@csiro.au schrieb:
> >BTW: what would you use for poison on a metal-eating, 
> >acid-breathing organism? 
> 
> a) Oxygen
> b) Radiation?? Thinking more of the effect of EM-like 
> pulse on the rest of their working (but bit out of my depth there, so 
 
> radiation itself may not be exactly what I'm after)

Most terran poisons do not use such brute-force approaches as 
corrosion/acids or radiation. They work by disrupting critical 
components of the target organism, e.g.by clotting blood, disrupting 
neurotransmitters, paralyzing muscles etc. 
You can PSB just about anything as a poison for your Oitjuan.

> >As far as I can tell, there is no reason why a 
> >creature with an exoskeleton can't have lungs.  

There are several ways in which an exoskeletal animal could have lungs. 


If you want a totally solid shell, you could have a two-chambered lung 
divided by a movable wall. Move the wall, and one lung exhales, while 
the other inhales and vice versa. 

Or you could have a shell of plates with flexibly linked edges. Think 
of a square box (without lid or bottom). By moving the edges, you can 
fold it down to completely flat or extend it to its full volume. Works 
for most polygonal cross-sections, - ecept the Oitjuans' triangular one 
:-(. 

The other question is how to get "air" to the various parts of the 
body. 
 
> Then it becomes a problem of growing tubules to the right 
> spots to get the "respiratory" material around the body. 

One possibility. The other one is to transpport it as part of the 
general circulatory system (i.e.in the "Blood") 

> Endoskeletal armour may be the most viable alternative in the long 
run. 

Probably true.

> >However, if the Oijuan do have lungs, and a 
> > cardiovascular system, they would probably pop. 
> 
> Not if their lungs are actually fluid filled. Which is an 
> option in a heavy atmosphere enviro anyway to increase efficiency and 
give  
> extra strength. The main reason many deep sea ones do is due to gas 
bladders  
> etc. 

Certainly depends on the athmospheric pressure you postulate. The 2-4 
athmospheres mentioned earlier are not that outlandish, actually - like 
diving 10-30 m. Most Terran organisms could adapt quite happily to air 
at that pressure, I suspect. 

Greetings