在探索人体的过程中，我们常常会发现一些被认为是“无用”的器官或结构，比如智齿、阑尾等等。其实它们背后隐藏着丰富的演化故事。这些“残余”部分不仅曾经承载过重要功能，现在仍然与我们的身体密切相关。
Everything in the body has some meaning.
We're gonna take a look, starting at the head and going all the way down to the toes, at some of the most interesting body parts that have often been categorized as maybe useless.
Auricular muscles.
Some people have muscles where they can wiggle their ears a little bit.
These are rare.
We have three on the outside, so these are remnant auricular muscles that originally had great functions, particularly with sound the way your dog or your cat do.
Even in many of the monkeys our ancestors ears are able to move a bit with sound, but now they've largely lost that function and they are usually considered vestigial.
The term ‘vestigial’ comes from the Latin meaning footprints, so there are structures that were thought to be sort of footprints in time, giving us little clues to what came before.
So we, when we hear a sound do not necessarily move our ears in that direction.
We tend to move our entire head towards the sound.
