Our body parts tell the story of where we came from. Some are useful, helping us live and thrive. Others? Not so much. Thanks to evolution, we have a collection of biological relics—leftovers from ancestors who had very different needs.

These parts don’t do much for us anymore. They stick around because evolution is not in a rush to clean house.

Wisdom Teeth Were Once Useful, Now a Nuisance

Take wisdom teeth. Early humans needed an extra set of molars to grind down raw meat and tough roots. Back then, jaws were bigger, leaving plenty of room for these teeth to grow in without a problem. Today? Not so much.

Diamond / Pexels / Our diets are softer, our jaws are smaller, and most of us don’t need the extra wisdom teeth.

That is why many people end up getting them removed. A painful and expensive procedure for teeth that don’t serve a real purpose anymore. About 35% of the population is now born without them.

The Appendix

Then there is the appendix, once a crucial organ for digesting fibrous plants. It was dismissed as useless for years, but new research suggests it might actually serve as a backup reservoir for good gut bacteria.

When an illness wipes out the microbiome, the appendix helps repopulate it.

That is a solid reason to keep it around, even if most people don’t think about it unless they are getting it removed. However, many people still suffer from appendicitis, which often leads to surgical removal.

Goosebumps

Goosebumps are another evolutionary relic. They helped our ancestors by making body hair stand up, creating insulation against the cold, or making them look bigger to scare off predators. But since most of us are not covered in thick fur, goosebumps today are more about emotions than survival.

Whether you are listening to an amazing song or watching a scary movie, that tiny, muscle-driven response still kicks in long after it stops being useful for warmth or intimidation. It is a biological reaction that no longer serves its original purpose, yet it persists.

The Tailbone

Our ancestors had tails for balance and climbing, but modern humans don’t need one. Yet, we still have a few fused vertebrae at the base of the spine, a tiny reminder of a tail that vanished millions of years ago.

Karolina / Pexels / While the tailbone no longer swishes behind us, it does serve as an anchor for some pelvic muscles.

Still, if evolution decided to phase it out entirely, we would probably get along just fine without it.

The Plantaris Muscle

The plantaris muscle is another relic that is sticking around for no good reason. It once helped our ancestors flex their feet for climbing, gripping, and running. Today, about 9% of people are born without it.

For those who have it, surgeons often remove it without issue when performing reconstructive procedures. If a body part can be discarded without any downside, that is a strong sign it has lost its original purpose.

Why Do These Parts Stick Around?

So, if these body parts are not useful, why do we still have them? The answer lies in evolution’s efficiency. Traits that don’t cause harm tend to linger simply because there is no pressure to eliminate them. Natural selection removes traits that are dangerous or disadvantageous, but if something doesn’t cause a problem, it often stays put.

Some of these parts may eventually disappear if they continue to serve no purpose, but evolution is not in a rush. We are beginning to see people born without certain body parts, proving that our biology is still changing over time.