At each level, some energy is lost as heat, so the amount of energy available to organisms at higher levels is less than the amount of energy available to organisms at lower levels. This means that the number of organisms decreases at each level as the food chain gets longer.
The energy flow in a food chain can be represented by a pyramid, with the producers at the bottom and the top predators at the top. The bottom of the pyramid is the widest because there are more plants than herbivores. The middle of the pyramid is narrower because there are fewer herbivores than carnivores. And the top of the pyramid is the narrowest because there are fewer top predators than any other organisms.
The energy flow in a food chain is essential for the survival of all organisms. Without it, there would be no way for energy to move from one organism to another, and eventually, all life would cease to exist.