Photo AI
Put a tick (✓) in the box next to the equation that shows how the net production of consumers, N, can be calculated where: I represents the chemical energy stored in ingested food F represents the chemical energy lost to the environment in faeces and urine R represents the respiratory loss to the environment - AQA - A-Level Biology - Question 2 - 2022 - Paper 2
Question 2
Put a tick (✓) in the box next to the equation that shows how the net production of consumers, N, can be calculated where: I represents the chemical energy stored in... show full transcript
Worked Solution & Example Answer:Put a tick (✓) in the box next to the equation that shows how the net production of consumers, N, can be calculated where: I represents the chemical energy stored in ingested food F represents the chemical energy lost to the environment in faeces and urine R represents the respiratory loss to the environment - AQA - A-Level Biology - Question 2 - 2022 - Paper 2
Step 1
Use Table 1 to calculate the percentage of all female cattle that were beef cows in the UK in December 2017.
Answer
To find the percentage of the female breeding herd that were beef cows, we can use the data from Table 1. In December 2017, the total number of female breeding cattle was 3.45 million, with 45% classified as beef cows.
Calculating this gives:
ext{Percentage of beef cows} = rac{45}{100} imes 3.45 ext{ million} = 1.5525 ext{ million}
Since the female breeding herd represented 48% of all female cattle in the UK, we can find the total female cattle population by:
ext{Total female cattle} = rac{3.45 ext{ million}}{0.48} ext{ million} = 7.1875 ext{ million}
Finally, the percentage of all female cattle that were beef cows is:
rac{1.5525 ext{ million}}{7.1875 ext{ million}} imes 100 ext{ %} = 21.6 ext{ %}
Step 2
Use Table 1 to calculate the increase in the number of dairy cows in the UK female breeding herd between December 2013 and December 2017.
Answer
In December 2013, the number of dairy cows was:
ext{Dairy cows in December 2013} = 54 ext{% of } 3.35 ext{ million} = 0.54 imes 3.35 ext{ million} = 1.801 ext{ million}
In December 2017, the number of dairy cows was:
ext{Dairy cows in December 2017} = 54 ext{% of } 3.45 ext{ million} = 0.54 imes 3.45 ext{ million} = 1.863 ext{ million}
The increase in the number of dairy cows is:
Step 3
Explain why farming cattle for humans to eat is less efficient than farming crops because of energy transfer.
Answer
Farming cattle is less efficient because of significant energy loss at each trophic level. When energy is transferred from one trophic level to another, approximately 90% of the energy is lost through respiration, excretion, and as heat. This means that only about 10% of energy is converted into biomass that can be consumed by the next trophic level.
In addition, farming cattle typically requires larger input energy compared to farming crops. For example, the energy needed for feed production, livestock care, and other farming practices must be factored in. Consequently, using crops directly for human consumption is usually more efficient than converting crops into animal protein.