In any ecosystem, energy flows from the producers, which are usually plants, to the various levels of consumers, such as herbivores, carnivores, and omnivores. However, at each level, some energy is lost as heat, waste, or metabolic processes, and only a portion of the energy is passed on to the next trophic level. Using the given information that the producers have 100% of the energy and a total amount of 140,000 kcal, we can calculate the energy available at each trophic level as follows:
Producers: 100% of the energy is available to the producers, which means that 140,000 kcal is available at this level.
Primary consumers: Herbivores consume the producers, and only about 10% of the energy is transferred to this level. Therefore, the primary consumers have 10% of 140,000 kcal, which is 14,000 kcal.
Secondary consumers: Carnivores that consume herbivores receive only about 10% of the energy available at the primary consumer level. Therefore, the secondary consumers have 10% of 14,000 kcal, which is 1,400 kcal.
Tertiary consumers: Top predators that consume other carnivores receive only about 10% of the energy available at the secondary consumer level. Therefore, the tertiary consumers have 10% of 1,400 kcal, which is 140 kcal.
As we can see from these calculations, the amount of energy available at each trophic level decreases significantly as we move up the food chain. This is because energy is lost at each level due to various factors, such as digestion, respiration, and waste. As a result, organisms at higher trophic levels need to consume larger amounts of food to obtain the energy they need to survive. This also explains why ecosystems typically have fewer top predators than lower-level consumers, as there is not enough energy available to support a large population of top predators.