Figure 5.4 : Bird wings and insect wing.

Example 2: Fin and flippers: The pectoral fins of fishes and flippers of dolphins are flattened organs used for swimming but both have different structure (Figure 5.5). The flippers are the modified pentadactyl forelimbs whereas fins are pentadactyl.   

 

Figure 5.5 : Pectoral Fin of shark and dolphin flippers.