If you consider the all the living things found in an ecosystem, as a pyramid of biomass, then photosynthetic organisms(producers) would be found on the bottom of the pyramid. This indicates that this trophic level contains the largest amount of biomass. All other levels above this one, rely on the previous level before it. Therefore, there will always be a greater amount of autotrophs(green plants) because due to photosynthesis, they are capturing sunlight directly and converting this energy into the chemical energy of glucose. As herbivores, in the next level of the pyramid eat the plants, they will obtain food energy. However, their biomass will be less because they are feeding on the plants below which have a greater amount of organisms. Also, herbivores lose energy when some of it is converted to heat.