Why do Pisces reptilian and amphibians have 2 or 3-chambered heart?

Pisces, or fish, as well as reptiles and amphibians, typically have 2 or 3-chambered hearts due to their evolutionary adaptations to different environments. Fish possess a 2-chambered heart, which efficiently pumps deoxygenated blood to the gills for oxygenation before circulating it to the body. Reptiles often have a 3-chambered heart, which separates oxygenated and deoxygenated blood to some extent, allowing for more efficient oxygen use during their more active lifestyles. Amphibians also have a 3-chambered heart, which supports their dual life in water and on land, facilitating both aquatic and terrestrial respiration.