In every ecosystem, energy is transferred along food chains from one trophic level to the next.

The trophic level is the position that an organism occupies in a food chain - what it eats and what eats it.

Energy is absorbed up a food chain, but at each trophic level, this amount of energy decreases rapidly

1st trophic: photosynthesis

2nd onwards:

- respiration

- excretion

- movement

- transport