Evolution of the heart in vertebrates:
- Vertebrates’ hearts evolved from simple, tubular structures in early fish to more complex, multi-chambered organs in mammals.
- Fish have a two-chambered heart with a single atrium and ventricle, while amphibians and reptiles have a three-chambered heart with two atria and one ventricle.
- Birds and mammals evolved a four-chambered heart, separating oxygenated and deoxygenated blood, allowing for efficient oxygen transport.
Vestigial organ: A vestigial organ is a structure that has lost its original function through evolution.
