Analogous structures are structures that are similar in unrelated organisms. The structures are similar because they evolved to do the same job, not because they were inherited from a common ancestor. For example, the wings of bats and birds, shown in Figure below, look similar on the outside.

Are analogous structures evidence of a common ancestor?

They may go through different developmental and functional stages before they are fully alike. Analogous structures are not necessarily evidence that two species came from a common ancestor.

Why do analogous structures not show a common ancestor?

Because analogous structures differ in anatomy as well as developmental origin they do not implicate a common ancestral origin. The features or traits common in them evolve independently.