Assume the biomass of the organism at the bottom of the trophic is 5,000 lbs. predict the approximate mass of each of the remaining levels, explain why the mass is changing.
To predict the approximate mass of each of the remaining trophic levels, you can use the ecological efficiency concept, which refers to the percentage of energy transferred from one trophic level to the next.
Ecological efficiency typically ranges from 5% to 20%, with an average of around 10%. For the purpose of this explanation, let's assume an ecological efficiency of 10%.
Level 2: Primary Consumers
Approximately 10% of the biomass from the previous trophic level is transferred to the primary consumers. Therefore, the approximate mass of the primary consumers would be 10% of 5,000 lbs, which is 500 lbs.
The mass decreases because only a fraction of the energy stored in the previous level is consumed and converted into biomass. Some energy is lost as waste, heat, or used for the organism's respiration and other metabolic activities.
Level 3: Secondary Consumers
Following the same logic, only 10% of the biomass from the primary consumers is transferred to the secondary consumers. Thus, the approximate mass of the secondary consumers would be 10% of 500 lbs, which is 50 lbs.
The mass continues to decrease as energy is lost at each trophic level, and only a fraction is converted into biomass. This pattern is known as the ecological pyramid, where the biomass decreases as we move up the food chain.
Level 4: Tertiary Consumers
Using the same ecological efficiency of 10%, we can predict that only 10% of the secondary consumer's biomass is transferred to the tertiary consumers. Therefore, the approximate mass of the tertiary consumers would be 10% of 50 lbs, which is 5 lbs.
The mass decreases because energy loss occurs at each step of the food chain. As organisms consume other organisms for energy, not all of the energy is passed on to the next level. Therefore, there is a reduction in biomass as we move up the trophic levels.
It's important to note that these calculations are simplified approximations based on the assumption of a constant ecological efficiency of 10%. In reality, ecological efficiency can vary depending on various factors such as the complexity of the food web and the specific ecosystem.