The structures that have similar origin, and are similar in their marphology, anatomy, genetics and embryology but perform different functions. Such types of organs said to be homologous organs.

The hearts in various vertebrates such as fishes, amphibians, reptiles, birds and mammals are homologous. They show similarity in the basic plan but they have a varied degree of specialization according to the habitat in which they live, energy requirements and scale of evolution.

ok