Organs That Humans Don't Need Anymore

There is no part of the human body which is completely useless. Whatever their ancient function or form, the human body finds new ways to utilize organs which have lost their original use.

We have changed our forms, diet and environment many times since life began on Earth, over a billion years ago. Today, we are completely unrecognizable from not just our distant ancestors, but also from our nearest relatives - chimps.

This transformation, like everything in nature, has rendered the human body into an efficient machine, fine-tuned to perfection. Every little cell and the tiny organelles work towards extracting the most out of our environment.

However, there are certain organs that have defied the laws of natural selection and persisted in our bodies even though they do not serve their primary function. Also called vestigial organs, these organs were once essential to our survival, but are not so vital anymore.

Although as per the ongoing research, these organs have taken up secondary functions, like supporting the surrounding muscles or tissues. Below is a short list of organs which do not serve their primary function anymore -

Also called caecum, is a part of the digestive system connected to the large intestine and is shaped like a pouch. In herbivores it is used for digesting cellulose - vegetal matter is stored in the cecum for a short time so as that the beneficial bacteria ferment the tough plant fiber and convert it into a form that can be absorbed by the body.

In humans and other habitual carnivores, it is often diminished in size and serves the same function as the rest of large intestine, absorbing water, minerals and salt from the digested matter, but is by no means essential for our survival.

Appendix is a worm-like appendage attached to the cecum at the right of abdomen. It is thought to be a remnant of a cecum, from when our ancestors had a largely herbivore diet, but now, many animals completely lack the structure. In humans, it's often removed due to appendicitis - an inflammation, which can be life-threatening with no apparent side-effects.

For many years, the human appendix was thought to serve no purpose at all, but new research has revealed that it has taken some immune functions - like restoring the gut flora after a GI infection.

It is also thought to 'train' the immune system of an infant, and might even be regulating hormones. However, infants born without an appendix have shown no serious consequences due to the absence of the organ.

Located just behind the tongue, on the palatine bone, tonsils are a part of the lymphatic system. They also form the first line of defense of our bodies, by trapping dust and germs before it can get inside the body. That being said, scientist are still unable to find the exact function and reason for the existence of tonsils.

The reason they are considered vestigial is that thousands of people undergo tonsillectomy every year and millions have had them removed in their childhood, due to infection or air-way obstruction.

Till date, no major consequence or negative effect has been observed. Even the filtering of foreign particles is taken up by surrounding tissues and the immune system is able to kill any extra germs that might have entered the body.

Coccyx, better known as tail bone, is the remnant of our tail. Our ancestors were tree-dwelling, and the tail was used for grasping, balance and mobility. As we moved from trees to land and then from being quadrupeds to bipeds, the need of the tail reduced. The 3 or in some cases 5 segments of coccyx is all that remains of the once fully functional tail.

The tailbone, is not completely useless though, as it serves as an attachment point for several muscles, ligaments and tendons. It also supports the weight of a person when he/she is sitting.

Besides these, there are also minor structures and muscles in our bodies that are not considered very useful anymore, such as -
The wisdom tooth was pretty useful when our diet consisted of hard, uncooked foods. The teeth would wear down requiring replacement by the third molars - the wisdom teeth.

But as our diets changed, our jaws got smaller and with better oral-hygiene, we don't lose as many teeth, rendering the replacement redundant.

The hair on our bodies was once used to regulate our temperature - in cold weather it would serve as an insulating layer. And in hot weather, it would help us cool off by aiding evaporation of sweat. These days, clothes and air conditioners are used for much the same purpose.

The erector pili or arrector pili muscles are the ones which give us goose bumps. They also make the hair stand on their ends - when we had dense body hair, it would make us look bigger to our predators. But, since we have shifted to cities and have little body hair, they are pretty much useless.

The plica semilunaris is the tiny remnant of a nictitating membrane in the corner of our eyes. It was once a fully functional translucent third eyelid - used for protection and keeping the eyes moist while still offering some visibility.

As stated earlier, no structure or organ in the human body or anywhere can be considered completely useless. However, humans can and do function pretty well without these organs, as their functions are mostly secondary and can be easily compensated for.

They can also be removed from our bodies without any major consequences and hence, it can be said that these are the organs that humans don't need anymore.