Explain why energy in most ecosystems must flow from the sun, then to autotrophs and finally to heterotrophs, in that order.

Answer:

Most ecosystems receive energy from sunlight. Autotrophs capture that light and convert it into chemical energy through photosynthesis. Heterotrophs cannot produce their own food, so they get this stored energy by eating autotrophs or other organisms. Thus, energy flows from the sun to autotrophs and then to heterotrophs.