AP BIOLOGY

Detailed explanation-1: -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-2: -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".

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: -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-5: -Common examples of vestigial structures are the hip bones that remain in snakes and whales. At a time, these species had ancestors that had limbs that required hips for mobility.