People have speculated over the nature of seemingly useless physical human characteristics for thousands of years. It wasn’t until the late 18th and early 19th centuries, though, that the idea of vestigiality would enter the public imagination ow.ly/jS5l30oigUH 
Examples of human vestigiality are numerous, including the anatomical, the behavioral, and molecular. Among behavioral, goosebumps are caused by your arrector pili, the smooth muscle fibers that contract involuntarily when you are stressed, excited or cold buff.ly/2FRw2u7
The palmar and plantar grasp reflex is found in infants of humans and most primates. When an object is placed in an infant's hand or close to a foot, the fingers or the toes will close reflexively, as the object is grasped via palmar grasp ow.ly/Vj3830oiid1
In modern humans, the appendix is a vestige of a redundant organ that in ancestral species had digestive functions, much as it still does in extant species in which intestinal flora hydrolyze cellulose and similar indigestible plant materials ow.ly/Miu430oij36
Your coccyx, better known as your tailbone, is the very last part of your vertebrae, and is the remnant of a lost tail. Between stages 14 and 22 of human embryogenesis, one can actually observe a tail-like structure that is later absorbed ow.ly/gNFb30oijxs
Wisdom teeth are vestigial molars that human ancestors used to grind down plant tissue. The skulls of human ancestors had larger jaws with more teeth & as human diets changed, smaller jaws were naturally selected, yet the 3rd molars still commonly develop ow.ly/nMae30oikb5
In about 10% of the human population, the outer rim of the ear (called the helix) has been known to show signs of vestigial features. A thickening of the helix called "Darwin's tubercle" occurs at the juncture of the upper and middle thirds of the ear ow.ly/dc9F30oikpl
The palmaris longus is a muscle visible touching the pads of the fourth finger and thumb. Apparently we needed this muscle way back when we needed to grasp spears, and now could become a mutational loss, since it's absent in roughly 1 in 100,000 people ow.ly/iBR930oile9
