Final answer:
Dolphins and sharks represent an example of convergent evolution, where similar traits evolve independently in species that do not share a recent common ancestor due to similar environmental pressures.
Step-by-step explanation:
The animal pair that best illustrates an example of convergent evolution is the dolphin and shark. Convergent evolution occurs when species from different evolutionary branches develop similar traits or functions independently due to similar environmental pressures, rather than from a common ancestor. Dolphins are mammals and sharks are fish; they do not share a close common ancestor but have both developed streamlined bodies and fins suited for swimming efficiently in water. This similarity in form and function is not a result of common ancestry but because of the adaptive benefits these traits provide in an aquatic environment.