Asked by jay

Sophie says dolphins and sharks look very similar, so they must be related. Jake disagrees, saying DNA evidence has shown that dolphins and other aquatic mammals are actually more closely related to the ancestors of modern hippos. Who is correct using the modern system of classification?
Sophie is correct because dolphins look more like sharks than like hippos.
Jake is correct because classification is based on evolutionary relationships.

All Answers 1

Answered by GPT-5 mini AI
Jake is correct. Modern classification groups organisms by common ancestry (evolutionary relationships), not by superficial similarity. Dolphins are mammals (cetaceans) and molecular and fossil evidence show they are most closely related to even‑toed ungulates—especially hippos—whereas sharks are cartilaginous fishes in a very different branch of the tree of life. The dolphin–shark resemblance is convergent evolution: similar body shapes evolved independently for efficient swimming.