1. Food Energy
Plants have specific organs in their cells that convert sunlight to food energy through a process known as photosynthesis. A plant will capture the suns rays in a chloroplast through a chemical reaction and this conversion gives plants the ability to supply calories to all life. It is by plants that cows are fed and then the humans that feed on the cows. In this way, sunlight provides the source of food for all life on earth.
2. Vitamin D
One of the amazing things sunlight provides for us is Vitamin D. It is absorbed through the skin and converted to a state that the body can use. It usually only requires about thirty minutes of sunlight a day to acquire a minimum dose. Vitamin D is important for the creation and maintenance of bones. It is involved in the use of calcium in the body and performs many other important jobs.
It takes the light of the sun eight minutes to reach us, and still it is only a fraction of the powerful heat generated by our star. Yes, it is the obvious perk of having a sun, but we would have nothing if there was no light. We use it to plant our crops, find shelter from the predators of the night, and to pursue the things we enjoy most. Without the light of the sun, there would not be any life on earth. There would be no star to orbit and no heat to sustain us. In short, without the life giving light of the sun, we would be a species lost. In fact, we would not even exist.