Rarely, by some genetic twitch, some remembrance of our evolutionary past appears in our bodies so conspicuously. It can be that genetic switch which covers the human body with so much hair as much as our genetic cousins, the apes or even those born with extra vertebrae which resemble a tail. This prompts superstitious folk to attribute what they see as a "monstrosity" to some evil spell, punishment for some wrong done or the will of the divine to send us some message. This really gets to me. I sometimes want to seize them by their mental collars to try to explain evolution, which is now even firmly supported by modern genetics, or even grab a comics-version (I do not know if there is one) of it to clear the cobwebs of their minds that no child is born under some mystical spell to look like it is less than human. When some rarity occurs and some unexpected body part shows up since it is no longer found in a majority of humans, it is not because the child’s mother took a special fondness for some animal bearing that trait. It is not psychology that did it but natural history. It is because we humans took 4.6 billion years to appear on Earth. It is only in the last 100,000 years that modern humans (Homo Sapien) evolved to look like who we are now. Richard Dawkins, one of the world’s most prominent evolutionary biologists in his book The Ancestor’s Tale: A Pilgrimage to the Dawn of Evolution (Houghton Mifflin: NY, 2004), helps us understand our own presence in the long chain of natural life by making us imagine that we are on a pilgrimage back in evolutionary time where at certain points, we were one with other species – mammals, reptiles, birds, etc. Thus, since what we look like now is part of a long process of evolution, it is not impossible that we still find vestiges of our evolutionary past, such as a tail, too much hair, extra toes or limbs. I am not saying that it is a desirable thing to have in present humans. I am saying that this is not a supernatural occurrence.
In an article in Discover Magazine (June 2004), Jocelyn Selim also explores human body parts that are remnants of what we used to be when we were one with animals with, for instance, receptors with a "bloodhound’s sense of smell" or with more teeth. Some humans still have these vestiges and all of us still have parts like "sinuses" which Selim says aside from moistening the air we inspire, have no apparent purpose for us while in animals with heightened sense of smell, their sinus cavities are lined with tissues sensitive to smell. Another is the coccyx or the fused vertebrae (about 3-5) which is all we have left from the tails we used to have. A third eyelid, Selim also discovered, found in the inner corner of the human eye is the humble remains of the eye membrane of our bird and mammalian ancestors which they used to filter debris from their eyes. Our goosebump muscles or "erector pili" are smooth muscle fibers that allowed our furry ancestors to "puff up" their fur to warm themselves or to scare predators. My nephew has "Darwin’s point," a fold on top of one of his ears which really droops when he is sad. Selim found out that this may be part of a larger ear part that helped home in on sound just like probably elephants do. Another is the plantaris muscle, useful to our simian cousins for grasping with their feet, which Selim says has already disappeared in nine percent of the human population. Interesting is the male uterus hanging off the male prostate gland which is a remnant of the female reproductive organ as well as a vas deferens in females which is what would have become sperm ducts in males. My favorite is the pyramidalis muscle which 20 percent of humans do not have anymore. It is a triangular muscle attached to the pubic bone suspected to be a vestige from marsupials with pouches (kangaroos!). I would have personally wanted that retained in humans to eliminate the need to carry bags.
So the next time you are horrified by the occasional conspicuous appearance of certain body parts you do not normally see in humans, please think again. The scariest and most dangerous thing is ignorance, not extra body parts. In parts not obvious to you and to others, you bear the biological remembrances of things past. Evolution dictates that we eventually grow or strengthen what we find useful to survive in the environment we find ourselves in and in the process, also shed what we do not find useful. But it takes time to do this and we seem to not be able to shed it all at the same time. Like parchment paper back in the days when paper was too expensive to have in abundance and text was erased and written over, there are shadows of what was once there. You are a palimpsest of what has gone on in natural life for over 3.8 billion years.
I always go back to Darwin’s Origin of Species when I need to remember my biological past. I am still surprised when people see me reading it and react like in the days of the Inquisition and think of me alongside thoughts of barbecue. But I love that book. Aside from the remarkable keenness by which Darwin observed a multitude of life forms in detail, it widens my range of what "normal" is in terms of appearance. I am still always surprised at what nature turns up but I am never horrified. This species I belong to, who for the most part behave as if all these exist to satisfy their sense of beauty and utility, is not a reasonable bunch. Flowers that we find so beautiful now have been around about 120 million years before our hominid ancestors with eyes to see them, appeared. The insects found those flowers "beautiful" before we ever did, and because they did, they fed on them, scattered their seeds and the world we know now looks and lives the way it does. It is no more or less beautiful but it is not so because humans are here to sense and judge it to be so. The beauty is in the largeness, complexity, diversity and succession of natural life that did not plan us but somehow, now includes us – beings with consciousness and intelligence to do science but not before we have expressed our sense of wonder and gratitude in the face of overwhelming mystery by saying "Wow!"