Homologous organ & Analogous organs
Homologous organs :- are organs which are similar in structure but
different in functions.
Eg :- The fore limbs of amphibians, reptiles, birds, and mammals have similar structures but different functions. Frog (amphibian) uses its fore limb to raise the front of the body. Lizard (reptile) uses its fore limb for walking and running. Birds fore limbs are modified as wings for flying. Mammals use the fore limbs for grasping, walking, running, swimming, flying etc. This shows evolutionary relationship.
Analogous organs :- are organs which are different in structures but similar in functions.
Eg :- The wings of butterfly, bird and bat have different structures but similar functions. This shows evolutionary relationship.