Photobiology is that branch of biological science which studies the interactions of light with living organisms. Here are some examples of these interactions. . .
Light is a necessary part of the process of photosynthesis - light is crucial for plant growth.
Light interacts with cells in the retina of the eye, so that we can see. Light is used to improve human health, a field of medicine known as photomedicine. Phototherapy is the use of light to treat of a variety of conditions, including cancer, leukemia, jaundice of the newborn and many skin conditions. Some organisms, for example fireflies and luminous bacteria, give off light as a result of chemical reactions taking place in specialized organs in their bodies. The intensity of light at different times of day has effects on the bodies of animals and humans - for example on the production of certain hormones, vitamin D and maybe even on some aspects of behavior.