Q. Are the limbs modified into wings of bats and the wings of birds instance of evolutionary homology or analogy? What about whale fins compared to fish fins?
Bird and Bat wings have the same function and the same origin (they are modified limbs) so they are homologous and analogous organs. Whale fins are a modification of the posterior limbs while fish fins although having the same function do not come from modified limbs so that they are analogous but not homologous structures. The appearance of similar features in evolutionarily distant species that explore the same type of environment in the mentioned case, the aquatic habitat, Evolutionary homology suggests common ancestry while biological analogy relates to the concept of evolutionary convergence.