Question

Which one is not a vestigial organ?
a. Wings of Kiwi
b. Coccyx in man
c. Pelvic girdle of python
d. Flipper of seal

Answer 1

Hint: The vestigial organs are the 'useless' body-parts. They are basically the remnants of lost functions, which once our ancestors possessed. They once represented a function which has eventually become dysfunctional over time.

Complete answer:
> Option D is correct, Vestigial organ or vestigiality refers to the genetically determined structures or attributes of an organism that have lost most or all of their ancestral function, but still have been retained through evolution. The assessment of the type or degree of vestigiality must be decided upon comparison with homologous features among their related species. The flipper of seal is not a vestigial organ as they are functional and actively used by the seals for swimming.

> Option A is incorrect, Wings of Kiwi are tiny and furry. Each of these wings has a small claw at the tip which has no known use.

> Option B is incorrect, Coccyx in man, which is also known as the tailbone, is a small, triangular bone that resembles a shortened tail. They are located at the bottom of the spine. It is composed of three to five coccygeal vertebrae or spinal bones. They are the vestigial organ and have no use.

> Option C is incorrect, The pelvic girdle of python has no connection with their spine; they simply float in the muscle mass. So, they are considered to be a vestigial organ of snakes.

Hence, The correct answer is option (D).

Note: A flipper in a seal is a broad, flattened limb which is adapted for movement through water. It is the fully webbed swimming appendages, which are absent in fishes. Some animals also contain two flippers, such as whales, where the flipper refers solely to the forelimbs.