The dorsal fin of a shark is to the dorsal fin of a dolphin. this anatomical feature is the result of convergent evolution (i. e., adaptation to similar environmental pressures).

the principles and empirical processes of discovery and demonstration considered characteristic of or necessary for scientific investigation, generally involving the observation of phenomena, the formulation of a hypothesis concerning the phenomena, experimentation to test the hypothesis, and development of a conclusion that confirms, rejects, or modifies the hypothesis.