Calculate the amount of energy available to lion in the following food chain if plants have 20000 J of energy available from the sun:
Plants `to` Deer `to` Lion

Explanation

(i) Plants can trap only 1% of the sun's energy falling on them. Now , `1%` of 20000 J is 200 J, so the plants have actually 200 J of energy available in them as food (The 10 per cent law does not apply at this stage).
(ii) The plants are eaten up by deer. Now, according to 10 per cent law, `10%` of 200 J, that is 20 J of energy will be available in deer as flesh food.
(iii) The deer will transfer `10%` of its 20 J energy to the lion. Thus, The food energy available to the lion will be `10%` of 20 J which comes to 2 J.
The above results can be shown more clearly as follows :
`{:(" Sun"),({:(" "20","000 J),((1% "absorbed")):}darr),(" "underset(200 J)"Plant"overset(10% " of "200J)(to)underset(20J)("Deer")overset(10% " of "20J)(to)underset(2J) ("Lion")):}`