All living organisms contain biological sensors that can detect light. This is way plant shoots will naturally grow towards a light source, and this response to light is called Photo tropism.
Plants need light for the process called photosynthesis, by which they prepare their food. Light also plays an important role in the flowering of plants. The opening and closing of some flowers' petals is also controlled by sunlight, and this kind of response to sunlight is called photonasty.
Some animals can respond to light in their surroundings and the main trigger for these color changes is light. light is also used as a cue for the timing of daily and seasonal rhythms in both plants and animals.