THE SENSE OF SIGHT
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THE SENSE OF SIGHT
The organs of sight, elements of great importance for survival. The human eye: description, characteristics, behaviour. Eyes of animals: characteristics of eyes of bats, single-celled animals, squids, chameleons, birds, mammals, insects and human-beings. Summary.
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2’17” INTRODUCTION
For many animals, their sense of sight is the most important of all their senses in so far as their survival is concerned
Most the information we humans receive from our exterior is perceived through our eyes.
The human eye works rather like a photographic camera.
2’37” THE HUMAN EYE
Through the eyes, two different images of the same subject, but from two different view-points, are offered to the brain which compares the two images, calculates distances involved and sees in three-dimensions.
Parts of the human eye.
How the human eye works.
Each species’sight is adapted to its needs.
3’38” ANIMALS
There are animals which don’t see, however they are sensitive to light.
Moles have scarcely any sense of sight.
Bats guide themselves by the echoes of the sounds they emit.
Squids have an exceptionally keen sight.
Snakes’s eyes are covered by a transparent lid. They are colour-blind.
Turtles enjoy excellent colour-vision.
The chameleon has spherical eyes.
Birds have very accurate vision.
The majority of mammals cannot see in colour. Their eyes quickly respond to movement.
Were we to have at either sides of our head, we would be able to see a great deal, but we would lose the capacity to see in 3 dimensions.
Carnivorous animals and primates have stereoscopic sight.
1’ 30” INSECTS
Insects have compound eyes, their eyes are made of certain number of visual units, called facets.
Each facet sends separate signals to the insect’s brain. Mosaic vision. Catching movement. Depending upon the species of the insect, eyes are made of different numbers of facets.
2’57” Summary |
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