10 Worst Adaptations in the Animal Kingdom

Wisdom Teeth
This patient seems to be the proud owner of all four of his or her wisdom teeth. That's going to be a fun time at the dentist. iStock/Thinkstock

Wisdom teeth are what we call a vestigial organ, or a part of our anatomy that's a remnant of an earlier time in human evolution. They served a purpose then, but now these organs are basically taking up space. So these vestigial organs are not so much an example of adaptations gone wrong, but a lack of adaptation. And that lack of adaptation means a lot of us have stories of swollen, bruised jaws and stomach-churning cases of dry socket after our "successful" wisdom teeth removal.

The problem is, our mouths used to be a lot bigger. And when our grins were wider, that meant we could fit more teeth in -- and we needed some big ol' molars to spring up. These teeth would help us crack and eat nuts, grind our leafy greens into a mushy pulp, and chew the gristle of the wild mastodon (never happened, but you get the idea).

But as our human brains evolved and invented Greek yogurt, we gradually didn't have much use for third molars. (Not to mention the fact our bodies literally couldn't fit them in our mouths anymore.) Our wisdom teeth -- so-called because they come in our late teens and early 20s when everyone is a real genius -- were causing more problems than they were worth by crowding our mouth and causing infection.