Vestigial organs are anatomical structures that have lost their original function through evolution, often being remnants of structures that were fully developed and functional in ancestral species. Wisdom teeth, or third molars, are an example of a vestigial structure in the human mouth.
Vestigial organs are organs, tissues or cells in a body which are no more functional the way they were in their ancestral form of the trait. It is authentication of evolution and hence, were helpful in explaining adaptation.

Such a structure can arise due to gene mutation which causes a change in the proteins. These mutated proteins result in the formation of vestigial structures.

Examples of Vestigial Organs
Following are a few examples of vestigial organs:

Sinuses
Human cheekbones hold the maxillary sinuses. The face consists of pockets of air called sinuses. They are lined by a thin layer of mucosa. It has no significant use but infection can lead to sinusitis.

Appendix
It is one of the most commonly known vestigial organs. This finger-like tube closed at one end arises from the vermiform process. In prime ancestors, the appendix is believed to have brought about the digestion of cellulose. Today, scientists predict that the appendix may play a role in digestion by bacteria.

Coccyx
It forms the last part of the vertebral column, the residue of the lost tail and is often termed as the tailbone. It is observed during human embryogenesis. This formed as the centrepiece of the ‘theory of recapitulation’.

Wisdom Tooth
Forms the third set of molars in our buccal cavity. They may have been significant in the past (chewing rough and raw food) but in modern times, as they are inaccessible and remote, it causes pain and infection.

External Ear
The Helix (outer rim of the ear) is known to be a vestigial structure. Underdeveloped muscles in the ear make us incapable to bring about the movement of ears. Darwin’s tubercle is a vestigial feature present on the juncture of the upper part of the ear.

Nictitating Membrane
Nictitating membrane is the third eyelid found in a few animals that protect and keep the eyes moist and also helps in vision. In humans, it is replaced by plica semilunaris.

Tonsils
The tonsils remain as vestigial organs in the human body. They act as the first line of defence and protect the body from harmful microorganisms that are either inhaled or ingested by the body.

Vestigial organs are body parts that have lost their original function over the course of evolution, often serving no useful purpose in the modern organism. An example of a vestigial structure in the human mouth is wisdom teeth (also known as third molars).

Wisdom Teeth:
Early humans had a diet that required more chewing and grinding, and wisdom teeth helped with this. However, as humans evolved and adopted a softer, more cooked diet, the need for these extra molars decreased.