Why do we have an appendix? Or wisdom teeth? My teacher said we don't need them. Also why do we have a tailbone? Doesn't that show we evolved?
Vestigial organs and structures are a classical example of the arrogance of some people. It has long been assumed that if a part of the body's function cannot be determined or that the person is able to function well without the part, then it must be a leftover from earlier mutations. But consider this: There are a lot of people who manage to function well while missing fingers, toes, or even whole limbs. Does it follow that these structures are not really needed and, therefore, useless leftovers? If we don't know the function of a part, does that mean the part has no function or that we are ignorant?
The funny part is that every part in the human body has now had its purpose identified. But the news hasn't reached the masses. People continue to quote outdated information.
Let's take the appendix. It isn't directly involved in digestion, which is why its function was unknown for so long. But it does have a purpose. Our gut depends on bacteria (flora) to aid our digestion. The appendix is a reservoir of that flora, so when something happens to wipe out the flora in our gut, the beneficial flora can be repopulated from the appendix. For example, when bad bacteria invades the gut, the body's reaction is flush it out, which we call diarrhea. The gut is then repopulated by the appendix. We also know that appendix is actively involved in our immune system. ["Appendix May Actually Have a Purpose," WebMD] and ["What Does the Appendix Do? Finally an Answer," News Medical]. Sure, we can function without it, but it doesn't mean we necessarily function as well.
Wisdom teeth as declared useless today because of our modern diet and modern dentistry, but it doesn't mean that the teeth serve no purpose. It has been noted that diet affects the shape of a human's jaw. Our modern diet tends to produce a shorter but wider jaw, which doesn't much room for the wisdom teeth. The hunter-gatherer diet tends to produce a longer narrower jaw, which has plenty of room for the wisdom teeth. In addition, before modern dentistry, it was common to lose teeth, the wisdom teeth helped fill in the gaps produced by lost teeth. ["Wisdom Teeth Reflect the Creator's Foresight," Reasons to Believe].
"The tailbone is commonly thought of as the remnant of an actual tail, left over from a time before we evolved into humans. Some describe it as a "vestigial tail," meaning it has no real purpose in our bodies. However, it does serve as an attachment site for muscles and ligaments, which makes this a misnomer. There are several muscles that attach to the tailbone, including the gluteus maximus, the levator ani, the sphincter ani externis and the coccygeus. These muscles all play important roles in standing, bowel control and pelvic floor support" ["About the Tail Bone," eHow].
In other words, unlike the appendix and wisdom teeth which we can manage to function without, the tailbone is a critical structure element. To call it vestigial means the person doesn't understand anatomy.
People are making the same silly comments about sections of our DNA code. We just recently began figuring out the purpose of a number of major sections of the DNA, but that has led people to claim that the sections we haven't figured out are vestigial. It is a false conclusion. Some sections have been already noted as having switching purposes (such as in timing development). Of course they are not currently active in adults, but it doesn't mean they are unneeded.