Salmon can be reared in fish farms where they are sometimes fed small fish such as anchovies - Scottish Highers Biology - Question 8 - 2018

Given that plant plankton fix 2% of the solar energy, we can set up the equation:

Let the total solar energy be denoted as $x$. Then, we have: $0.02x = 500000$ Solving for $x$, we find: $x = \frac{500000}{0.02} = 25000000$

Thus, the total solar energy to which the plant plankton were exposed is 25,000,000 kJ.

The term used to define the ability of the human population to access food of sufficient quantity is 'food security'.

The advantage of consuming anchovies rather than salmon lies in the energy transfer efficiency across trophic levels. Anchovies are at a lower trophic level compared to salmon, thus they have less energy lost in biological processes. This means that more energy is available for human consumption when anchovies are eaten, as there is less energy loss through each trophic level due to fewer organisms in the food chain.