Page "Comparative anatomy" Paragraph 5

# Analogous structures-structures similar in different organisms because they evolved in a similar environment, rather than were inherited from a recent common ancestor.

They usually serve the same or similar purposes.

An example is the streamlined torpedo body shape of porpoises and sharks.

So even though they evolved from different ancestors, porpoises and sharks developed analogous structures as a result of their evolution in the same aquatic environment.