Question

A paleontologist finds a fragment of a fossilized vertebrate that indicates that the animal had a four-chambered heart with two atria and two ventricles; it also had two aortas, one emerging from each ventricle. The animal could have been a/an:

a. amphibian.

b. bird.

c. crocodile.

d. fish.

e. mammal.

Answer 1

Ans.

• Unlike other reptiles, crocodiles have a heart that is divided into 4 chambers with two atria and two ventricles.
• A muscle septum divide them completely.
• 3 major blood vessels are also present which lead away from the heart and the two aortas emerges from each ventricles.
• The left ventricle give rise to the right aorta whereas the right ventricles give rise to the pulmonary artery and the left aorta.
• Blood from the right aorta is delivered to the brain and anterior circulation whereas viscera and posterior parts of the animal recieves blood from the left aorta.
• The point of connection of these two aorta in circulation is known as the foramen of Panizza.