Question

What are vestigial organs . Give one example.

Answer 1

Hint: Evolution is the process of formation of complex organisms through change from simple ancestral types over the course of geological time. It is a constant process that has resulted in an enormous variety of plants and animals that have come to exist on this earth at present.

Complete Answer:
Vestigial organs are tissues or cells in a body which are non functional but they were functional in their ancestral form of the trait. These structures arise due to gene mutation. These mutated genes form the vestigial structures. These structures may increase if it is beneficial in the population. For example in humans vestigial organs are appendix which is due to non-functioning shrinking in size and disappearing.
Following are few examples of vestigial organs in humans.
>Coccyx: it is present at the last part of vertebral column
>Sinuses: The human face has pockets of air which are called sinuses. They are lined by a thin layer of mucosa.
>Nictitating membrane: It is found in few animals which protect eyes from dust and moist.in humans it is replaced by a plica semilunaris.
>Tonsils: In the human body they act as a first line of defence and protect the body from harmful microorganisms.
>External ear: The outer rim of ear is a vestigial organ. In the ear some underdeveloped muscles are incapable to bring about movement of ears.
 >WISDOM TOOTH
In our buccal cavity wisdom tooth forms the third set of molar.They were used in rough chewing in the past but in morden times they are remote which causes pain and infection.

Note: In animal the description of other vestigial organs are as follows:
->Eye structures are found in blind fish and salamanders but they live in caves.
->Wings are present on cockroaches but females do not facilitate flying.
->The whale shark is a filter feeder. It has a row of teeth but they are not able to bite anything.