The Sun: An Essential Key in Food Chains

From polar bears to crocodiles to even humans, all organisms need the sun to survive. Though the sun may be on the bottom of the food chain, every organism relies on the sun's energy and resources to prosper.
Many people think that plants and fungi are on the bottom of the food chain. Yet as organisms, they must have someway to consume energy. This is done through photosynthesis. The plants absorb energy through sunlight and make it into glucose. So say in a desert food chain, a coyote eats a roadrunner, who eats a snake, who eats a mouse, who eats a cactus, who absorbs sunlight. So, if the sun is blocked out, the cactus that the mouse should have eaten does not grow so the mouse starves to death. The same happens to the snake, roadtunner, and coyote. And right there is whole region wiped out due to the absense of the sun. So, the sun is important to everyone. Even us humans. We eat animals that eat plants that use sunlight. So we, as omnivores, would starve from the lack of plants and animals if the sun should cease to serve it's purpose. In conclution, for a sucessful ecosystem, the sun is a valuble factor.

Valuble info from: http://http://digital-desert.com/wildlife/food-chains/