Caption: "A simplified food web model of energy and mineral nutrient flow in an ecosystem. Energy flow is unidirectional (noncyclic) and mineral nutrient flow is cyclic." (Slightly edited.)

The image illustrates that energy analysis (making use of conservation of energy principle during energy transformations) often gives partial information easily while getting full information is often very hard. This boon of energy analysis is why if finds so much use in physics and many other fields.

To elucidate the image in brief: electromagnetic radiation (EMR) from the Sun mainly in visible band (∼ 0.380--0.750 μm)chemical energy and macroscopic mechanical energy (i.e., kinetic energy and gravitational potential energy) in biota → dissipation to waste heat energy all along the way → ultimately re-radiation to space as infrared radiation EMR mainly in the near infrared band (∼ 0.750--1.4 μm).

In physics, we follow the energy rather than "follow the money".

See Energy Explication below/at (local link / general link: energy_explication.html).