The importance of homologous organs in the process of evolution is explained as follows:
i. Organs in different species which have a common anatomical plan but perform different functions are known as homologous organs.
ii. Organisms showing homologous organs indicate that they share a common ancestor, which had a similar internal body plan.
iii. Example: Forelimbs of humans, lizards and frogs; all of these have a five-finger arrangement but serve different functions.