4/1/2024 0 Comments Predator vs prey eye placementIn most vertebrates and some molluscs, the eye works by allowing light to enter and project onto a light-sensitive panel of cells, known as the retina, at the rear of the eye. The last common ancestor of animals possessed the biochemical toolkit necessary for vision, and more advanced eyes have evolved in 96% of animal species in six of the ~35 main phyla. The first proto-eyes evolved among animals 600 million years ago about the time of the Cambrian explosion. In other organisms, eyes are located so as to maximise the field of view, such as in rabbits and horses, which have monocular vision. The visual fields of many organisms, especially predators, involve large areas of binocular vision to improve depth perception. From more complex eyes, retinal photosensitive ganglion cells send signals along the retinohypothalamic tract to the suprachiasmatic nuclei to effect circadian adjustment.Ĭomplex eyes can distinguish shapes and colours. The simplest “eyes”, such as those in microorganisms, do nothing but detect whether the surroundings are light or dark, which is sufficient for the entrainment of circadian rhythms. Image-resolving eyes are present in molluscs, chordates and arthropods. Eyes with resolving power have come in ten fundamentally different forms, and 96% of animal species possess a complex optical system. In higher organisms the eye is a complex optical system which collects light from the surrounding environment, regulates its intensity through a diaphragm, focuses it through an adjustable assembly of lenses to form an image, converts this image into a set of electrical signals, and transmits these signals to the brain through complex neural pathways that connect the eye via the optic nerve to the visual cortex and other areas of the brain. The simplest photoreceptor cells in conscious vision connect light to movement. They detect light and convert it into electro-chemical impulses in neurons. Take a look at the evolution of the eye, including the difference in the eyes of predator and prey.Įyes are the organs of vision. He is the president of the World Eye Organisation, A charitable organization dedicated to the prevention and treatment of eye disorders for the poor. He studied under two Nobel Laureates at Harvard Medical School before joining the Harvard Faculty and subsequently became Professor of Ophthalmology and Chairman of Center for Biotechnology at Baylor College of Medicine in Houston. Lam was born in Swatow, and grew up in Hong Kong. This accompanying text below on this post was sent to us by friend of Webvision, Dr. Also note that we have an excellent chapter on the Evolution of Phototransduction, Vertebrate Photoreceptors and Retina by Trevor Lamb here on Webvision. The evolution of visual systems is something that we here at Webvision are very interested in. This amazing video produced by the History Channel, Vision and Evolution of the Eye is well worth 40 minutes of your time.
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