If you want evidence of evolution by natural selection, look no further than your own body. Whether it's your tailbone, goosebumps, or a weird little tendon on your inner wrist, the human body is covered with parts that don’t serve any purpose to us anymore. Yet they’re still there as a genetic relic from our evolutionary past. The same is true for many other animals – just think of the wings on an ostrich. These are called “vestigial” characteristics.