The appendix is a small, finger-shaped pouch attached to the large intestine. It has long been considered a vestigial organ, meaning that it has no function in the human body. However, recent research suggests that the appendix may actually serve as a reservoir for beneficial gut bacteria.

The appendix is an example of a Phenotype Variation — a trait that varies among individuals. In fact, something like 1 in 100,000 people are born without an appendix. The presence or absence of the appendix is one example of a variation in humans. However, the presence or absence of the appendix is not a typical example of phenotype variation, as it is not a continuous range of variation within a population. Nonetheless, it is an interesting variation that our descendants over the next eons will certainly observe.