These are called trophic levels . They feed on the primary producers. Decomposers break down organic matter and recycle it back to the primary consumers. The King Vulture is a decomposer as it feeds on dead animals. Fungi and bacteria are decomposers.
Food pyramids show relationships between the above trophic levels.
A pyramid of numbers would show the actual total number of organisms at each trophic level for a given area. The greatest number of organisms would be at the primary producer level, decreasing greatly as you move up the pyramid. A pyramid of energy would show the energy available at each trophic level for a given area. As you move up the pyramid the amount of energy available is drastically reduced. Much energy is lost as heat and through respiration.