How is time perceived by animals?

20 years Biodiversity Day

The healthy human eye is able to take in more than ten million pieces of information every second, to pass it on to the brain and to process it there. Around 95 percent of our visual abilities and performance are provided from one point in the eye: the macula, also known as the yellow spot. The macula forms the center of the retina and helps us, among other things, to see sharp and colored and to distinguish between light and dark. The well over 100 million visual cells that make up the retina are in turn divided into two significant types: cones and rods. The cones are more sensitive to light and help us to perceive colors. The rods ensure our twilight and night vision. Like any organ, the eye can develop deficits.

People diagnosed with “myopia” find it difficult to see things in the distance, but at closer range they see perfectly. Myopia is usually caused by an eyeball that is too long or that the refractive index of the lens is too high. So that we can see clearly, the light rays arriving in parallel must be precisely bundled and refracted on the retina. In a nearsighted person, however, the rays of light meet in front of the retina. Far-sightedness, on the other hand, is characterized by the fact that it is easy to see into the distance, but the precise recognition of objects in the vicinity causes problems for affected people. The effect that takes place in the eye is also reversed. The eyeball is usually too short or the refractive power of the eye too weak to focus incident rays in the retina. The light is therefore only bundled behind the focal point. The red-green weakness, in which people can hardly distinguish the colors red and green, usually occurs more frequently in men. The reason is that the genes for the red and green cones are positioned on the X chromosome. Since men only have one X chromosome, they are more likely to have a genetic defect than women, who, thanks to their two X chromosomes, can still see normally in color even if one of the chromosomes has a genetic defect.



Swell:

  • https://www.livescience.com/32559-why-do-we-see-in-color.html
  • https://www.planet-wissen.de/natur/sinne/sehen/index.html