Question

Trace blood flow through the amphibian and crocodilian hearts. What problems or anatomical features did early anatomist observe that led to the hypothesis that these taxa were intermediate or imperfect in CVS design based on heart structure? Why do these animals have these types of “intermediate hearts”?  

Answer 1

These are said to have intermediate heart because they have three chambered heart or they have twro atria and one ventricle.

There is mixing of oxygenated and deoxygenated blood in the ventricle.

The blood in the ventricle goes to the lungs and the rest of body.

The oxygenated blood from lungs goes to left atrium through pulmonary vein and the deoxygenated blood from the body goes to right atrium through venous sinuses. Then both the oxygenated and deoxygenated blood go to the single ventricle where its mixing occurs. The body doesnot get fully oxygen saturated blood that is why it is less efficient cvs in these animals.