Essay On Compound Eyes

1072 Words 5 Pages
The two different types
There are two types of eyes in the world of today. There are what one calls compound eyes and there are vertebrate eyes. Compound eyes also known as Arthropod eyes, can be traced back to an arthropod called trilobite. These ancestors didn 't have complex lenses like those of today but instead, their eyes and lenses were made of the same rock that made their skin - calcite. Compound eyes today contain many ommatidia (singular: ommatidium) which consist of a corneal lens, a crystalline cone, a rhabdom (a light-sensitive receptor), and a retinula cell (a sense cell). Originally there was only one ommatidium but eventually, multiple ommatidia were added as needed for evolutionary advantage. The advantage being that if more ommatidia were present the
…show more content…
This was attached to a flagellum so that there was no need of a brain to interpret what was being seen, it went directly to the muscle. As evolution progressed, the light-sensitive proteins started to make a concave cup-holed shape which made it easier to perceive the direction where the light was coming from. The purpose of this was simple; where there was light there was food, and where there was shade there was protection from predators. The deeper the cup, the more resolution the organism had. As time elapsed, transparent cells covered the pinhole to prevent infection allowing the inside to fill with fluid which optimized light sensitivity. Crystalline proteins then developed which allowed focusing light into a single point on the retina, this was the beginning of the lens. The lens thanks to ciliary muscles allowed for the accommodation of distances so that the image would be sharp whether the distance was near or far. Other additions were made such as the sclera to maintain structure and to protect from further injury, irises which manage how much light is allowed into the eye, and the tear glands which lubricate the eye and make a protective layer. Irises are believed to work

Related Documents

Related Topics