Question

There are 4000 units of energy available to grass at the first trophic level of an ecosystem. If the grass is eaten by a mouse and the mouse is eaten by an owl, how many units of energy will be left for the bobcat that eventually eats the owl?

Answer 1

When one organism eats another organism, it gets about 10% of its energy.

For example...the grass has 4000 units of energy.

When the mouse eats the grass, the mouse gets 10% of the grass' energy.
10% of 4000 is 400.
The mouse gets 400 units of energy, from eating the grass.

You get it?

The owl eats the mouse.
If the mouse has 400 units of energy, how many units will the owl get?

The bobcat eats the owl.
How many units of energy will the bobcat get?