Question

In the given food chain, suppose the amount of energy in the fourth trophic level is 5KJ, what will be the energy available at the producer level? Grass—grasshopper—frog—snake—hawk.
(a)5KJ
(b)50KJ
(c)500KJ
(d)5000KJ

Answer 1

10 percent of the energy in the food is fixed into its flesh as animals are eaten and are usable for the next trophic stage (carnivores or omnivores). When an animal is eaten by a carnivore or an omnivore, just about 10 percent of the energy is fixed at a higher level in its flesh.

Complete answer:
There is a lack of energy in an ecosystem along with the food chain and only 10 percent of the energy available at each trophic stage is passed onto the next trophic level. Thus, if 5000 KJ of energy is available initially, 500 KJ of energy will be available at the next (or second) trophic level, 50 KJ of energy will be available at the next (or third) trophic level, and 5 KJ of energy will be available at the next (or fourth) trophic level.

Additional Information: In ecology, the food chain is the series of transfers of matter and energy from organism to organism in the form of food. As most species eat more than one form of animal or plant, food chains intertwine locally into a food web. The primary source of food plants, which transform solar energy into food through photosynthesis. A plant-eating animal is consumed by a flesh-eating animal in a predator chain. A smaller organism eats part of a bigger host in a parasite chain and can itself be parasitized by even smaller species. Microorganisms survive on the dead organic matter within a saprophytic chain.
So, the correct answer is ‘5000KJ’.

Note: Since energy is lost at each stage, or trophic level, in the form of heat, chains do not usually cover more than four or five trophic levels. By taking out one step in the food chain, people will increase the overall food supply: instead of eating animals that eat cereal grains, people themselves consume the grains. As the food chain is shorter, the total quantity of resources at the disposal of the final consumers is increased.