AP BIOLOGY

Detailed explanation-1: -Pelvic bones in snakes are an example of a . . . . What conclusion can you draw from the fact that many modern whale species have vestigial pelvic and leg bones? The ancestors of whales may have been land mammals.

Detailed explanation-2: -Both whales and dolphins have pelvic (hip) bones, evolutionary remnants from when their ancestors walked on land more than 40 million years ago. Common wisdom has long held that those bones are simply vestigial, slowly withering away like tailbones on humans.

Detailed explanation-3: -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.

Detailed explanation-4: -So, whales have a vestigial pelvis, a remnant of the pelvis once possessed by land mammals. Flippers evolved from forelimbs. There are bones in the flippers homologous to bones in the forelimbs of land animals. Hipbones and hind limbs disappeared as land mammals became whales.

Detailed explanation-5: -Looking at a whale’s body and biology, there are plenty of clues that their ancestors lived on land. They breathe air and nurse their young with their own milk, they also have paddle-shaped flippers which encase hand bones with five ‘fingers’. As embryos, whales have tiny back limbs which disappear before birth.