Re: Warm-Blooded debate

[Dinogeorge@aol.com]

In a message dated 97-06-22 17:44:00 EDT, tons@ccs.netside.com (Michael)
writes:

<< Also, AFAIK, ectotherms have the basic tools at the cellular level 
 for their mitochondria to use fuel aerobically.  AFAIK, only 
 cyanobacteria, those bacteria that use non-organic material, and a 
 few eukaryotic bacteria are obligatory anaerobic organisms. >>

The other problem with the three-chambered heart that relates to aerobic
metabolism is the amount of mixing that occurs in the ventricle between
pulmonary and systemic blood. Ingenious mechanisms do keep the two
circulations reasonably separate under normal circumstances in tetrapods with
three-chambered hearts, but some deoxygenated blood does return to the
systemic circulation along with the oxygenated blood. In tetrapods with
four-chambered hearts, this doesn't usually happen, and consequently their
aerobic metabolism is better.