September 28, 2012 1:14
In lizards have a small point at the top of the head, which is called the parietal eye. This eye is not as complicated or useful as the other two in front of the head, but at least he reacts to light.
Does this mean that in the future will be the descendants of the modern three-eyed lizard? No, it's just a vestigial trait.
In fact, the majority of animals (and humans as well) had a chance to get a third eye, but we refused.
Tuatara — an endangered species, it remained only a few islands of New Zealand, all of which declared reserve. It really looks like a lizard, but in reality it is not. It is a living fossil, which reminds us of a time when the four-legged turned into turtles, lizards, crocodiles and dinosaurs. Since then (and it's been 200 million years), it has not changed, and therefore enable us to judge how it would look like "contemporaries."
So, it boasts an animal form at the top of the head, which, more than anything else in other beings, like a third eye.
Additional body gives many evolutionary advantages. The ability to look up and the more back would be useful to almost any form. But for some reason, turtles, crocodiles and birds lost this education.
Perhaps the most remarkable feature of the third eye is that it is symmetrical. If mentally draw a line that divides the body in half, you will notice that the left and right sides of the same, even in the developing organism. In place of the eyes appear first indentations, which gradually deepened, they formed more subtle ocular structures.
The parietal eye is not deepened. Instead, the bulge is formed, under which developed two symmetrical areas of the brain. They acquire different functions: the left is the parietal eye, and the right — the pineal bag. Reptiles parietal eye perceives light and pineal bag releases melatonin — a hormone that regulates sleep cycles.
People instead of pineal sac, located near the eye at the top of the head, there is the pineal gland, which is at the bottom, next to the rest of the brain. It also produces melatonin and many other hormones, which are aimed at regulating the neurological processes (the most famous of them — serotonin). Serviceable pineal gland makes people focused and happy, makes waking up in the morning and go to sleep at night, and in some measure to prevent neural degeneration, inevitable with age.
Apparently, this is the reason why our ancestors gave up the third eye: for the sake of healthy sleep, happy and full of the psyche.
And, of course, beautiful hair.