EVERYDAY SCIENCE

Detailed explanation-1: -Pelvic girdle and hind limbs are vestigial in aquatic mammals like whales. Sharks are cartilaginous fish.

Detailed explanation-2: -Vestigial pelvic girdle means the pelvic bone is present but they do not perform any function that’s why it is known as vestigial pelvic girdle. Whales are large mammals. It is a tetrapod with flippers. The flippers are the forelimbs of the whale.

Detailed explanation-3: -The pelvic bones of whales are “one of the classic examples of a vestigial structure, ” said Otárola-Castillo. “But what we found was that the shapes of these bones are highly associated with the mating systems of these whales and dolphins-species that are more promiscuous have more-complex-shaped pelves.”

Detailed explanation-4: -New study turns a long-accepted evolutionary assumption on its head, finding that whale pelvic bones play a key role in mating.

Detailed explanation-5: -For example, whales have pelvic bones which are unused and therefore vestigial, but the presence of the pelvic bone suggests a time in the past where whales were in a position (possibly on land) to use that bone, revealing part of their history-a “trace".