AP BIOLOGY

Detailed explanation-1: -Structures like the human tail bone and whale pelvis are called vestigial structures . Evolution has reduced their size because the structures are no longer used. The human appendix is another example of a vestigial structure. It is a tiny remnant of a once-larger organ.

Detailed explanation-2: -These unused structures without function are called vestigial structures. Other examples of vestigial structures are wings on flightless birds, leaves on some cacti, and hind leg bones in whales.

Detailed explanation-3: -(This is fossil evidence in support of the theory of evolution.) Modern whales lack hindlimbs, but have tiny bones in their skeletons which are the remnants of pelvic and leg bones.

Detailed explanation-4: -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.

Detailed explanation-5: -These structures, which are often reduced in size, are known as vestigial structures. Examples of vestigial structures include the tailbone of humans (a vestigial tail), the hind leg bones of whales, and the underdeveloped legs found in some snakes (see picture at right).