Final answer:
A four-chambered heart is more efficient than a three-chambered heart due to its ability to separate oxygenated and deoxygenated blood, facilitating double circulation and efficient oxygen delivery for the high-energy demands of warm-blooded birds and mammals.
Step-by-step explanation:
A four-chambered heart is more efficient than a three-chambered heart because it separates oxygenated and deoxygenated blood, which enables double circulation. This separation is crucial for the efficient movement of oxygen and nutrients to the body's cells, which is particularly necessary for the high metabolism of warm-blooded animals like birds and mammals. The evolution of a four-chambered heart from a three-chambered heart is an example of convergent evolution, indicating its effectiveness in various species.
Furthermore, the anatomy of the heart in vertebrates shows an increasing complexity, with fish having a two-chambered heart, amphibians and reptiles typically having a three-chambered heart (with some reptiles having partially separated ventricles), and birds and mammals having a four-chambered heart. The four-chambered heart's design with its unique cardiac muscle, one-way valves, and vessels is specifically designed to efficiently transport oxygen to body cells and remove carbon dioxide, contributing to the organism's ability to maintain a stable internal environment and respond quickly to environmental changes.