Describe the evolutionary change in the pattern of heart among the vertebrates.
As it is clear from the following diagram the heart of fish has two chambers. This means there is no separate circulation for oxygenated and deoxygenated blood. There is separation of two chambers in the atrium of amphibians. This has further evolved to partial separation of ventricle in reptiles. Finally in birds there is complete separation of oxygenated and deoxygenated blood circulation with advent of four chambers in the heart. Mammal heart is the most developed having the most efficient double circulatory system.
