Why do organisms need enzymes to survive?

Digestive enzymes speed up reactions that break down large molecules of carbohydrates, proteins, and fats into smaller molecules the body can use. Without digestive enzymes, animals would not be able to break down food molecules quickly enough to provide the energy and nutrients they need to survive

The answer your looking for is a food chain grid. it describes how nature can support itself and survival of the fittest comes into play..