Question

The amount of available energy changes between the trophic levels found in a food chain or energy pyramid.

A food chain. Arrows point from one stage to the next. The stages are leaves, mouse, snake, hawk.

Photos (left to right) by Mehmet Karatay, Jens Buurgaard Nielsen, Furryscaly, and Walter Siegmund

How would the amount of available energy differ in the trophic level of the mouse compared to the trophic level of the hawk?

a.
Available energy would increase from the mouse to the hawk.
b.
Available energy would decrease from the mouse to the hawk.
c.
Available energy would initially increase from the mouse to the hawk, and then decrease over time.
d.
Available energy would remain the same from the mouse to the hawk.

Answer 1

b. Available energy would decrease from the mouse to the hawk.

Energy is lost at each trophic transfer (respiration, heat, waste), so only a small fraction (roughly 10%) is passed to the next level.