The term ’vestigial organs’ refers to those ’extra’ organs or structures in the human body that are no longer functional. They have long been considered classic proof of evolution, showing the difference between modern humans and our ancestors.
We here at Think About Network thought we’d tell you about some of them — it makes for a fascinating little science lesson. Observe the evidence for evolution in your own body!
The long palmar muscle
Put your hand palm-up on a table or other flat surface. Bring your thumb and little finger together and hold them in that position. Do you see a ligament showing through the skin in your wrist? This muscle is the legacy of our ancestors. It was responsible for flexing the hand and helped our predecessors grip onto things when jumping from tree to tree. Don’t worry if you don’t have it — the muscle is absolutely useless today!
People get goose bumps when they’re cold or stressed. Goosebumps are created when the spinal cord signal causes contractions of tiny muscles attached to each hair that pull the hair up. When it’s cold, goosebumps reduce heat loss, which helps the body warm up. They can also be a response to anger or fear: the erect hairs make an animal look larger. Goosebumps can also appear when you experience strong emotions such as admiration or pleasure.
The epicanthic fold
The epicanthic fold is the official term for the skin fold on the upper eyelid that many people from various parts of Asia have. Most researchers believe that epicanthic fold used to be useful for humans who lived in extreme conditions, such as severe cold, intense heat or desert areas.
This tiny nodule at the inner corner of the eye is, in fact, a relic of the nictitating membrane. It is found in many species, including fish, birds and reptiles, and is used for protecting and moisturizing the eye. Over time, the nictitating membrane has become useless to humans, but we still have a small piece of this membrane joined to the muscles in our eyes.
Ear muscles are a classic example of a vestigial organ. They helped our ancestors to move their ears to better detect approaching predators, opponents, relatives or prey. Today very few people can move their ears.
Wisdom teeth once served an important function — they helped us chew hard and tough pieces of food. Today, we mainly consume processed or refined foods, meaning that the eighth tooth on each side of your mouth has no function in the body any more. This is why half of the population lack these third molars entirely.