Our body is made up of 13 organ systems, each having multiple organs. Each and every organ has its own special function or does it? Thanks to evolution, each organism has some organs and features that are now rendered useless. Some of these organs have disappeared, but a few still remain, making our evolutionary history very clear. These organs/features/functions are termed vestigial organs. Here are a few of them.
Wisdom teeth: Used by our ancestors to grind plant tissue, the third set of molars has slowly become quite useless. If compared to the earlier humans, the size of our jaws has become considerably smaller because the food that we eat has become more processed. Since the premolars and the first two sets of molars do a good job, some people do not have to undergo the painful process of the wisdom teeth coming out. Most people have to get them extracted sooner or later, anyway.
Appendix: The appendix is a part of the cecum, a pouch that connects the small intestine to the colon, part of the large intestine. This tiny organ came in handy when our herbivore ancestors needed to digest the cellulose present in plants. This part of the intestines is diminished in modern day carnivores, but humans still have it. Even though all it does is laze around, it sometimes gets infected and causes immense pain. It then has to be operated on and taken out. Well, good riddance!
Coccyx: We sometimes forget, but we are mammals, and all mammals had tails at some point of time. Humans have them when they are just 33-day-old embryos and it continues growing for 20 days more and then stops. After that the embryo starts looking more human and is called a foetus. Even though we do not have an external tail, the coccyx or the tailbone still serves the purpose of being a point of attachment for muscles. Some babies are still born with external tails and they are usually operated immediately after birth.
Darwin’s tubercle: Humans have lost the ability to move their ears at will like a few species of monkeys can. The various neck movements that the humans can perform compensated for this loss and that helped in listening better, but some muscles still remain and a few people can move their ears. The most visible evolutionary trait in a human ear though is the Darwin’s tubercle. If you run your finger on the rim of your ear, somewhere on the top one-thirds you will feel a thickening. According to Charles Darwin, this is where the ears were pointed. Yes, we at one time had pointy ears like elves. But unfortunately, the points ran out of use and thus were lost.
Nictitating membrane: Birds have it, fish have it, reptiles have it, and amphibians have it. Mammals do not have it, but the traces remain. I am talking about the nictitating membrane or the third eye lid that gives protection to the eye from damage by wind and water. In other creatures it is a translucent material that closes like a sliding door while they can still keep their eyes open. We can say that mammals had it at some point because of the pink, muscly thing in the inner corners of our eyes. That is all that remains of our third eyelid because, well, if we need to protect our eyes now, we just close them.