Have you ever wondered about why you grow wisdom teeth, only to have them removed? And what's the deal with the tailbone?
Humans have many vestigial body parts that may have been useful for our ancestors but are obsolete for us.
Useless body parts explained:
Useless Body Parts
Why do we have useless body parts?
Why do I have wisdom teeth, if they just need to be taken out?
In prehistoric times, our jaws were larger, and able to accommodate all 32 teeth. Our diets consisted of tougher foods, like roots and raw meat, so we needed the extra teeth to grind it down.
As we evolved, our brains became larger, and our jaws became smaller, leaving no room for the extra molars.
Did you know you have a third eyelid?
The small patch of skin in the inner corner of our eyelids is the remnant of a third eyelid.
Birds and reptiles use their third eyelids to perform a lateral blink to clean their cornea. Humans may have been able, at one point, to use their third eyelids, but today, the organ is reduced to a fold of skin.
Why do I have a tailbone?
The tailbone is a set of 3-5 vertebrae at the end of our backbones. Our ancestors used to have tails, but as they evolved to walk upright, their tails became unnecessary and they eventually evolved without them.
Humans still have a tail during the first trimester of pregnancy, but later in development, the tail is dissolved by white blood cells, leaving the tailbone behind.