What Evolution Left Behind On Humans

I’ve always been fascinated with human evolution. To me, the most fascinating part of human evolution is learning about what was “left behind” on our bodies from our ancestors and from our prenatal development.

• Appendix
  • We all know about this one. You might even know someone who has had it removed. The appendix is a narrow, muscular tube attached to the large intestine. A common misconception is that this organ was used for digesting raw meat. It was actually used in our plant chewing days; it was the special area for digesting cellulose. Since our diets have changed, we no longer need this organ.
• Paranasal Sinuses
  • For as far back as I can remember, my mother always had sinus problems. Sometimes so bad she’d have to lay down just to make the pain bearable. Ironically, the sinus cavity serves little to no purpose for a human. The only function they serve now for humans is making our heads lighter (weight wise), and adding warmth and moisture to the air we breath.In animals with an heightened sense of smell (like a dog or cat), the sinus cavities are lined with olfactory tissues. Some scientists believe that our ancestors had a much better sense of smell (our DNA contains broken genes for additional odor receptors) but for some reason we lost that ability.
• Vomeronasal Organ
  • A tiny pit on each side of the septum is lined with non functioning chemo-receptors. They may be all that remains of a once extensive pheromone-detecting ability.Taken from Wikipedia:
    

    Anatomical studies demonstrate that in the vomeronasal organ regresses during fetal development, as is the case with some other mammals, including apes, cetaceans, and some bats. There is no evidence of a neural connection between the organ and the brain in adult humans. Nevertheless, a small pit can be found in the nasal septum of some people, and some researchers have argued that this pit represents a functional vomeronasal organ. Thus, its possible presence in humans remains controversial.

• Coccyx (AKA: The Tail Bone)
  • The coccyx is a set of fused vertebrae at the bottom of the spinal column. This is another useless remain of our ancestral past. It’s all that’s left of our tails, which disappeared from hominids before they began walking upright. All it does now is cause a lot of pain if you fall on your butt.
• Extrinsic Ear Muscles
  • These three muscles most likely made it possible for prehominids to move their ears independently of their heads (again, like a cat or dog). Again, we still have these muscles which is why most people can learn how to wiggle their ears.
• Toes
  • Technically, humans don’t need any of our toes except our big toe (for balance). Our toes were used for grasping and climbing.
• Neck Rib
  • This is a set of cervical ribs commonly thought to be left-overs from the age of reptiles. They still appear in less than 1% of humans. Unfortunately these can cause nerve and artery problems. Talk about bad luck.
• Third Eyelid
  • Somewhere down the early evolutionary line we actually had a third eye lid, much like you see on a frog, for example. Humans retain a tiny fold in the inner corner of the eye.
• Darwin’s Point
  • Take your finger and run it along the the inner edge of your ear. Near the top you’ll notice a small piece of skin that is almost like a point. If you can’t find it, don’t worry. Not all humans still carry this. They believe that this may be a remain of a larger shape that helped us focus on distant sounds.
• Subclavius Muscle
  • There is a muscle stretching under our shoulder from the first rib to the collarbone. This would still be a useful muscle if humans walked on all fours. Not all humans have one. Some don’t have one, and a small few actually have two.
• Palmaris Muscle
  • This muscle (if you have it, only 11% of humans do) is a long and narrow muscle that runs from the elbow to the wrist. They believe once it may have been an important muscle for hanging and climbing. If you ever need reconstructive surgery, this muscle might be taken for that. Thumbs up for free body parts, right?
• Male Nipples
  • Lactiferous ducts (the lobes of the mammary gland at the tip of the nipple) form well before the the testosterone that causes a fetus to be a male occurs. Men have mammary tissue that can be simulated to produce milk.
• Wisdom Teeth
  • If you’re reading this, you’ve probably had your wisdom teeth remove. I had all 4 of mine pulled when I was in high school. Despite what you think, these teeth weren’t totally useless. Since early humans had to chew a lot of plants to intake the amount of calories needed to survive, the more teeth the better.Another theory regarding wisdom teeth, that is more of an additional to the main theory (that we used them to chew on plants) is that they were replacement teeth that were lost from wear and tear.
• Erector Pili (AKA: Goosebumps)
  • These are bundles of smooth muscle fibers that allow animals to puff up their fur to intimidate others (like a cat, for example) or for insulation. We still retain this ability even though we lost most of our fur.
• Body Hair
  • Most of your body hair serves no function (though some think otherwise). Eyebrows keep sweat from going into your eyes, and male facial hair may play a role in sexual selection, but that really is it. Arm and leg hair are just the remains of a once fully covered body of hair.
• Thirteenth Rib
  • While our closest cousins (chimps and gorillas) still retain this extra set of ribs. Most humans have 12 though 8% of the population have the extra ribs.
• Male Uterus
  • The remains of the undeveloped female reproductive organ hangs off of the male prostate gland.
• Female Vas Deferens
  • These are thought to become sperm ducts in males but they become epoophoron in females. It is a cluster of useless dead-end tubules near the ovaries.