Evidences of Evolution: Homologous Organs

Homologous organs have the same basic structure and embryonic origin (anatomical similarity), but they may perform different functions in different animals.
Example: the forelimbs of whale (flipper), bat (wing), cheetah (running) and human (grasping) all have the same set of bones (humerus, radius-ulna, carpals, metacarpals, phalanges). In plants, thorns of Bougainvillea and tendrils of Cucurbita are homologous.
They show divergent evolution from a common ancestor.
Organs that differ in structure but do the same function are analogous; organs without function now are vestigial.
So homologous structures are organs with anatomical similarities but performing different functions.

Homologous organs have the same basic structure and embryonic origin but may perform different functions.
The wings of a bird and the pectoral fins of a fish are both vertebrate forelimbs (paired anterior appendages) with the same basic plan of bones and the same origin. So they are homologous.
The wings of birds and insects (locust, butterfly), wings of bat and butterfly, and legs of frog and cockroach perform similar functions but have completely different structure and origin, so they are analogous organs.
So the homologous organs are the wings of birds (sparrow) and the pectoral fins of fish.