Question

5. Only about 10 percent of the energy in an organism is passed on to the next level of a food chain. Look at this food chain: grass → rabbit → hawk
What percentage of the energy stored by the grass is passed on to the hawk?

Answer 1

In any food chain, the percentage of energy passed from one level to another usually reduced by a factor of 10%.

In the food chain given in the question, we are told that the rabbit ate grass and the hawk ate the rabbit.

The grass carried out photosynthesis and obtained 100% energy from the sun. When the rabbit ate the grass, he obtained 10% of the energy from the grass, thus, the quantity of energy it gained from eating the grass is 10%, that is, 100/10  = 10%.

When the hawk ate the rabbit, it was only able to get 10% of the energy in the rabbit, thus, the quantity of the energy it gained is 1%, that is 10/10 = 1%.

Therefore, 1% of the energy stored by the grass is passed on to the hawk.