The sun provides more than enough energy to drive things. In any nontrivial system with lots of energy flowing through it, you are almost certain to find order arising somewhere in the system. The solar energy is stored in the starch. Small biomass compared to photosynthesis. Thus, to produce 1kg of tuna, you will need 10000kg of phytoplankton.
Different regions have differring efficiencies of energy and mass transfer.
The Primary Producers are the plants and chemosynthetic organisms. This is considerably simplified, because there can be considerable crossover. A. A more realistic Food Web is shown in Figure 12.4. Note that even this is simplified, because the top predator shown is only the herring, which is of course preyed upon by many other organisms. Below that, enough light is not present for the plant to produce biomass, although the plant can still live.