How many herbivores can a given number of plants feed? And how many carnivores?

Life is a dissipative structure, i.e. a system in dynamic equilibrium that uses the sun’s low entropy energy to perform work, create ordered structures and degrade heat.

The energy conversion factor from one trophic level to another is approximately 10%. This means that only 10% of the sun’s energy is used by plants, another tenth is used by herbivores and the same for carnivores.

Approximately 1000 plants can feed 100 herbivores, which in turn can feed 10 primary consumers and one apex predator. This explains why the hunting area of super predators must be so large, and highlights the importance of vegetation in sustaining a diverse ecosystem.

The abundance of water and light in the tropics is in fact a heaven for plants, which are in turn able to support a large number of very different species.

The opposite happens moving away from the equator: more unfavorable conditions for plants make the rest of the ecosystem less diverse. Curiously, however, despite the lower biodiversity, the population of individual species is greater than in the tropics, where a myriad of different species with small populations coexist.