The human body is one of the most complex things to exist in nature. There are thousands of complex mechanisms going on inside the body that helps us to function, but it is not all perfect. There are many flaws in the human body. Evolution can be blamed for most of them. Like Alan Mann, a physical anthropologist at Princeton University, says, “Evolution doesn’t produce perfection. It produces function.” So we bring you 10 such basic design flaws in the human body, all thanks to evolution.

1 Allergies are basically the body attacking itself because of the presence of a foreign substance which in the majority of cases is harmless to the body.

Allergies are hypersensitive reactions by the human body in response to an alien substance that either enters or comes in contact with the body. Such substances include pet dander, pollen, or bee venom. There is no fixed number of allergens. Any substance can be treated as an allergen by the human body. It just varies from person to person. But the shocking part is most of the allergens are not harmful. In short, allergies are just an unnecessary overreaction by the human body towards harmless substances. To top it all off, some allergic reactions are so severe that they can be fatal.

This is one of the biggest flaws of the human body. The immune system reacts because it does not have the necessary antibodies to attack the foreign substance. But this only happens to select individuals. Most of us already have the required antibodies. A better design would have been the body already equipped with every antibody. Evolution should have done that already, no? (source)

2 We experience excruciating pain from a tiny hole in the tooth, but we can get cancer and not know for years.

People who have gone through a root canal procedure should be familiar with this. A simple decay in a tooth can lead to sleepless and extremely painful nights. The pain is so excruciating that immediate medical care is required. On the other hand, a person can suffer from cancer for many years before the symptoms are detected. That sounds a bit unfair considering the gravity of the disease here.

A National Cancer Patient ­Experience survey determined that out of the 71,793 patients, 25% of them said that they had visited their General Physician more than three times before being told to go for tests. Moreover, as of 2015, one in four British cancer patients are unlikely to live longer than six months due to late cancer diagnosis. Most of the diagnosis happens at either the third or fourth stage, and, by then, it’s too late for the treatment to work. Most people do not even realize they are suffering from cancer until they arrive at the Accident and Emergency wards. And even then, only 36% make it past one year. It would have been much better if the human body responded with excruciating pain for cancer rather than a tooth infection. (1, 2, 3)

3 Eyelashes falling loose and ending up in the one place they are supposed to protect, the eyes!

One of the primary reasons our eyes have eyelashes is to protect the eyes. The air around us is filled with particles such as dust and sand. These particles might cause irritation if they make their way into our eyes in large volumes. So, the eyelashes work to keep these particles away from the eyes. This is the reason why camels have such long eyelashes! But due to a simple flaw in the human anatomy, the eyelashes are defeating their own purpose! Sometimes when an eyelash comes loose, it makes its way inside the eyes and causes a lot of irritability.

Even the design of our eyelids is also pathetic when compared to other animals. Most animals have two sets of eyelids. One is opaque, similar to the ones we have, that keeps out the light, and the other is transparent and a clear “nictitating membrane.” The clear membrane helps to keep out dust and water and at the same time does not impair sight.  If we had a nictitating membrane, many of the eye problems would not even exist. (source)

4 A tiny blood clot has the ability to kill a person in a second. 

Its true, a small blood clot can take a person’s life. Known as “deep vein thrombosis” (DVT), these tiny blood clots occur when the blood thickens and forms clumps. Mostly, they originate in the lower legs or thighs. If the clot breaks off from the vein, it enters into the bloodstream and travels along with it. If the clot reaches the lungs and blocks the blood flow into it, it gives rise to a condition known as a “pulmonary embolism” (PE). PE is quite serious. It has the potential to damage the lungs, other organs, and even cause death under extreme circumstances.

The veins and arteries are very narrow and having clots travel through them and creating blockages is a serious flaw. (source)

5 We have “myopic” or “hypermetropic” eyes, not because of any injury or overuse, but because our eyes are too long or too short. A vast majority of people suffer from visual problems in their lifetime. 

Eyes are considered to be one of the most important organs for humans. Then why is it that the human eye is full of functional issues? More than 70% of people in the Asian countries suffer from short-sightedness. All the eye defects that we suffer from are the fault of the eyes. Having a myopic eye means that your eye is simply too long. The image focuses before it reaches the back of the eye and falls out of focus when the light finally hits the retina. The opposite happens in case of hypermetropia. The eye is just too short. The image focusses after the light has crossed the retina. Basically, the eye is just a simple and plain bad design!

Human vision would be put to shame if compared with the vision of birds. Birds have excellent visual abilities. They can even see a broader range of wavelengths. We do not require such great visual abilities as birds, but our design could have been a little better so as to avoid the simple eye defects. (source)