AP BIOLOGY

Detailed explanation-1: -The pelvis and femur in whales are considered vestigial structures. These structures were inherited from ancestors that had a use for them, but are no longer used today. Whales evolved from animals that used to walk on land. Thus, these ancestors needed a pelvis and femur bones to do so.

Detailed explanation-2: -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-3: -1: Whale Skeleton: The pelvic bones in whales are also a good example of vestigial evolution (whales evolved from four-legged land mammals and secondarily lost their hind legs).

Detailed explanation-4: -Other vestigial reports on sea mammals could be cited, but enough has been presented to show that these rudimentary hind limbs do exist in cetaceans and are truly vestigial. Being vestigial, they point to an earlier stage of evolutionary development.

Detailed explanation-5: -A vestigial structure is a biological structure that has lost a major ancestral function and is usually drastically reduced in size. Well-known examples include the eyes of blind cave fishes and blind cave salamanders, and the diminutive wings of kiwis and emus.