A rabbit (primary consumer) is preyed upon and consumed by a fox (secondary consumer). Before being consumed, the rabbit ate leaves and berries containing 20 kJ of energy. How many kilojoules of the energy from the leaves and berries did the fox obtain from eating the rabbit?
To determine the amount of energy the fox obtained from eating the rabbit, we need to consider the energy transfer between trophic levels.
Typically, only around 10% of the energy from one trophic level is transferred to the next trophic level. This is known as the 10% rule.
Given that the rabbit obtained 20 kJ of energy from eating leaves and berries, we can calculate the amount of energy the fox obtained by multiplying this amount by 10%:
Energy obtained by fox = 20 kJ x 10% = 2 kJ
Therefore, the fox obtained 2 kilojoules of energy from eating the rabbit.
To determine how many kilojoules of energy the fox obtained from eating the rabbit, we need to consider the energy transfer within the food chain.
In this case, the rabbit is a primary consumer, meaning it obtains energy by consuming plants (leaves and berries). The energy it obtains from these plants is referred to as primary productivity.
The fox, as a secondary consumer, obtains energy by consuming the rabbit. The energy transferred from the rabbit to the fox is called secondary productivity.
To estimate the energy transfer from one trophic level to another, we can use the concept of ecological efficiency. Ecological efficiency describes the proportion of energy transferred from one trophic level to the next.
In general, ecological efficiency ranges from 10% to 20%. For this explanation, let's assume an ecological efficiency of 15%. This means that 15% of the energy available at one trophic level is transferred to the next trophic level.
Given that the rabbit obtained 20 kJ of energy from the leaves and berries, we can calculate the energy obtained by the fox using the formula:
Energy obtained by the fox = Energy obtained by the rabbit * Ecological efficiency
Energy obtained by the fox = 20 kJ * 0.15
Energy obtained by the fox = 3 kJ
Therefore, the fox obtained approximately 3 kilojoules of energy from eating the rabbit.
Here is what I think.
If the rabbit had just eaten the berries and leaves then the fox obtain ALL of the 20 kJ of energy. If the rabbit ate the leaves, say an hour ago, then the rabbit used up some of the 20 kJ moving around and the fox obtained less than 20 kJ.