WHY WE HAVE TWO EYES?

Photos lack depth perception. The above photo clearly illustrates that. Because the photos are shot with a single eye or lens

. We have two eyes separated by a distance of 2.5 inches. The two eyes see the same scene or object in two different angles. Hence two slightly different images fall on the retina of the eyes. Brain process these images and gives the depth perception or third dimension.

Thousands of years back, we required two eyes for hunting and to escape from wild animals. Today, we require depth perception for crossing a busy road!! Only using two eyes, we can estimate the distance of approaching vehicles and take a decision to cross the road.

Consider the birds like chickens and pigeons. They have two eyes, one on the left side and the other on right side of the head. Hence they get a 360-degree view of the world. It will help them to easily escape from predators. But there is a price to pay. They lack binocular vision like us and lose depth perception. To overcome this drawback, the birds always bob their heads. When they move the heads up and down, they get two images. These images are processed by the brain and give them 3D -effect.

Similarly, two ears give us depth perception in sound. You can tell where the 'cry for help' is coming from, front or back, left or right.

Meanwhile - enjoy 2.0 -3D.
Some people say we do not use the depth perception as much as a caveman (like Tarzan hoping from tree to tree). Hence, evolution may wipe out our two eyes. Instead, we may get a single eye at the centre of the head.
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