Role of light in natural system

light is not only a vital factor but also a limiting one, both at the maximum and minimum levels. Although the direct exposure of protoplasm to light is fatal, yet light it the ultimate source of energy without which life cannot exist. Due to the effect of light, there are various changes in structural and  behavioural characteristics of organisms. There is also a primary role of solar radiation on ecosystem and energetics. Long radio-waves have positive effects on migrating birds or on other organisms.