BIOL 102 Lecture Notes - Lecture 28: Electromagnetic Spectrum, Ommatidium, Retina
Document Summary
Not all organisms need eyes to detect light. For example the c. reinhardtii has an eyespot to detect light. The eyespot allows the organism to detect light direction and intensity and using the flagellum it can either swim towards or away from the light and this is called phototaxis (movement of a cell in response to light) Phototaxis allows the cell to stay in the optimum light environment to maximize light capture for processes such as photosynthesis. When the light is absorbed by the eyespot , rapid changes in the ion concentrations occur (k and ca) which causes some electrical events which changes the beating pattern of the flagella used for locomotion. Animals use the eye as an organ to sense light. For vision, the animal must have a brain or a simple nervous system that can interpret the signals coming from the eye.
