Photosynthetic organisms are at the bottom of the food chain and provide the chemical energy that the rest of use. They also provide the oxygen needed for respiration. Given how important light is to life, it is no wonder that there are many types of interactions between light and living organisms. Visualization and Spatial orientation. Plants and microorganisms use light to orient themselves spatially and to guide their movements or growth.
Most higher animals are capable of using light to image their surroundings.
Nature has developed sensitive photoreceptors, such as the rhodopsin in your eye, which can convert light energy into a chemical signal. From the way that the light changes with time, organisms can not only tell whether it is night or day but also what time of year it is. For example, many plants use this to determine when to flower. Again sensitive biological photoreceptors are used for this purpose. Conversion of light energy to chemical energy.