Whales still have vestigial hipbones - they lost their pelvic girdles over milli

Question

Whales still have vestigial hipbones - they lost their pelvic girdles over millions of years. How much longer (long time, short time, etc - not in years!) do you think it will it take for whales to lose their vestigial pelvic bones? Please provide some supporting evidence for your hypothesis.

An excerpt on vestigial bones is provided below:

"As environmental changes select against some structures, others persist even if they are not used. A vestigial structure has no apparent function in one species, yet it is homologous to a functional organ in another. (Darwin compared vestigial structures to silent letters in a word, such as the “g” in night; they are not pronounced, but they offer clues to the word's origin.) In some whales and snakes, tiny leg bones are vestigial, retained from vertebrate ancestors that used legs to walk on land (figure 13.9).

Humans have several vestigial organs. The tiny muscles that make hairs stand on end helped our furry ancestors conserve heat or show aggression; in us, they apparently serve only as the basis of goose bumps. Human embryos have tails, which usually disintegrate long before birth; in other vertebrates, tails persist into adulthood. We also retain a trio of muscles that help other mammals move their ears in a way that improves hearing (most of us can't use these muscles). Each vestigial structure links us to other animals that still use these features.

Figure 13.9

Vestigial Structures.(a) Some snakes have tiny hind leg bones that are vestigial but (b) detectable only in the skeleton. (c) Some whales likewise have a vestigial pelvis and hind limbs.

Explanation / Answer

Basically whale lost their pelvic girdles over a millians of year ago. so it will become a vestigial organ. because it didn't show adaptation to the enviroment or may not use pelvic girdle so it will be became unfunctinal so natural selection avoid the development of pelvic girdle for the next generation. if it shows adaptation then it will be developed in next generation. so we can understand by the process of natural selection through the adaptation. natural selection posesses set of traits hat confer the adaptation in a given environment by the reproduction to the next generation. but in whale pelvic girdles are vestigial so it means oelvic girdle didn't have adaptation to the environment so natural selection leave its development in next generation. as next generations developed pelvic girdles became vestigial organ in whales.

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