The shark (a fish) and the dolphin (a mammal) are an example of A - VCE - SSCE Biology - Question 17 - 2006 - Paper 1

Convergent evolution occurs when different species evolve similar traits or adaptations independently, often because they occupy similar ecological niches or face similar environmental pressures. In this case, sharks and dolphins have both adapted to living in aquatic environments despite being from different evolutionary lineages—sharks are fish, while dolphins are mammals. Their streamlined bodies and fins are adaptations to their environment, exemplifying convergent evolution.