Why do fish only have 2 heart chambers?
The 2-chambered heart is a simple organ that pumps blood for animals with gills and single circulation. Because blood leaves the gills and immediately circulates to the rest of the body, the heart does not require additional chambers beyond the first two.
Does fish have 3 chamber heart?
Fishes have only two chambers of the heart- the atrium and ventricle.
What animals have a 4 chamber heart?
Birds and mammals, however, have a fully septated ventricle–a bona fide four-chambered heart. This configuration ensures the separation of low-pressure circulation to the lungs, and high-pressure pumping into the rest of the body.