9 useless body parts that humans no longer need

• Some human body parts have become useless over the past few million years.
• Useless body parts include the appendix, the tail bone, and the muscle fibers that produce goose bumps.

Some human body parts serve no purpose despite once having a specific function among our ancestors.

The appendix, for example, is not an essential body part (though some research suggests it may act as storage for good bacteria). In some cases, the appendix gets inflamed or ruptures, which requires surgical removal of the organ.

Several other body parts used to be important for humans' survival, but they have since become useless. Some of them can be removed, and their absence does not lower people's quality of life.

Take a look at nine of the most useless body parts. 

The appendix may be the most commonly known useless organ.

Many years ago, the appendix may have helped people digest plants that were rich in cellulose, Gizmodo reported. 

Plant-eating vertebrates still rely on their appendix to help process plants, but the organ is not part of the human digestive system.

Read more: Appendix removal is linked to lower risk of Parkinson's

Humans no longer need very powerful jaws because our diets have shifted toward soft foods and cooked grains. Our jaws are also smaller, so we can't all fit our wisdom teeth properly.

Arrector pili are muscle fibers that produce goose bumps when they contract. Our ancestors, who had a lot more body hair, used these fibers to their advantage, but we don't have a use for them anymore.

For animals with thick fur, arrector pili can help provide insulation. The fibers can also make animals look bigger — a porcupine benefits from this phenomenon.