Posted by Xespok on 17-03-2006 20:46
#28
Kahis wrote:
It's time for yet another hypothesis :) The food is exposed to air leading to modifications in it's chemical composition by oxygenation. This would also radically change the microbial fauna of the liquid as most bacteria of the alimentary canal are anaerobic and will quickly perish when exposed to the terrible poison gas called oxygen:D
A couple of remarks with this hypothesis:
Why would flies need aerobic processes for what most other organisms mostly use anaerobic processes. The fundamental problem with the aerobicity is that, like us aerobic organisms degrade the carbon source to CO2, and this is no longer use to the fly. Anaerobic organisms degrade the carbon source to small monomers, part of which they ferment to low Carbon acids and alcohols which can be further utilized.
I do not know how the digestion works in Arthropods, but I assume the same general principles apply that define the rules for us vertebratates.
That is exactly why regions of our gastrointestinal tract that might be aerobic (down to the beginning of the small intestines) contain normally a low amount of natural flora. (bad luck if you have ulcer).
Also the statement that anaerobic organisms quickly persih in aerobic conditons are very very far away from being true. In fact a very large fraction of the anaerobs show a hight degree of oxygen tolerance. Being aerob just means to be able to utilize oxygen as an electron acceptor while preserving energy. Being oxygen tolerant means that getting rid of oxygen costs extra energy. The resilience of the anerobic organisms of our gut to oxygen explains how these creatures travel from one individual to another, which inevitably involves spending time in aerobic niches.
Edited by Xespok on 17-03-2006 20:46