With so many body parts, can we expect them all to be useful? LiveScience lists those that do bugger-all, like wisdom teeth and body hair. To wit:
- Wisdom teeth: Our jaws have gotten smaller, so wisdom teeth can't fit anymore. Plus dental hygiene keeps our teeth from falling out and making room for the bulky molars.
- Tailbone: When our ancestors no longer needed tails for balance, evolution turned them into fused vertebrae called a coccyx.
- Male nipples: All fetuses have nipples, before testosterone makes each baby male or female. Ergo men's useless nipples. Note that some men have even lactated or gotten breast cancer.
- Body hair and Erector Pili: Conflict and fear can activate muscle fibers called erector pili in many animals, making body hair stand on end. Great for scaring off enemies—not so useful for us.
Click for the full list.