Question

Why humans, unlike fishes have four chambered heart?

Answer 1

Dear student,

Fishes are cold-blooded organisms and possess the simplest vertebrate heart. The heart is only two chambered– atrium and the other is ventricle. Deoxygenated blood is pumped through heart to the gills for oxygenation. It then passes directly to the rest of the body from gills. Thus, blood passes only once during each cardiac cycle.
On the other hand, humans are much evolved organisms. Humans are warm-blooded animals and maintain a constant body temperature according to the environment. Hence, we humans require more oxygen for more cellular respiration so that more energy could be produced to maintain the body temperature. To keep separated oxygenated and de-oxygenated blood,four-chambered heart is required so that the circulatory system is more efficient and our body can maintain a constant temperature according to the environment.

Regards