This is the subject which describe about sun light and their effects on plants and animals. Sunlight is most important element of our environment. Photobiology includes many topics such as, most important photosynthesis, photo-medicine, environmental photobiology, and photo-sensory ( important for plant biology).
1) Effect of sunlight on Plant photo-sensory, and
2) Effect of sunlight on human.
a) Photomorphogenesis : Nature produced many light absorbing molecules that turn on the organisms to responding in the changing natural light environment. Some examples are seed germination, leaf expansion, stem elongation, flower initiations, and pigment synthesis.
b) Chronobiology: The ability to differentiate time of day without reference to taking external light, this property found in both plant and animals.
c) Photomovement : This activity define the movement of any organism in light, e.g bending of plants.
Sun-light cause many health problems, raises skin problems, due to UV rays. Skin is the largest part of our body and directly exposers to the light, which cause the skin problems. Here some other examples of health problems which is unique and potentially dangerous, raises by UV radiations a) Genotoxic changes in which gene mutation occurs, which cause skin cancers. And it is also beneficial in some cases like vitamin D synthesis in human body, which is essential for calcium metabolism and human skeletons.