AQA GCSE Biology Foundation (8461), Foundation tier · Ecology › Food production
Practise Farming techniques. 7 exam-style questions plus unlimited generated ones on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
How farmers make food production more efficient by reducing the energy transferred from animals to the environment, and the ethical objections to intensive farming. Expect to explain why limiting movement and controlling temperature increase growth, and to evaluate intensive farming. This subtopic is in GCSE Biology only, not Combined Science.
Key facts
Restrict energy transfer from food animals to the environment
Limit movement → less energy used for movement
Warm surroundings → less energy transferred to keep warm
High-protein food → faster growth
More of the food eaten becomes biomass (more efficient)
Objections: welfare, crowding, disease spread, antibiotic resistance, energy use
% of food converted to biomass = gain in mass ÷ mass of food eaten × 100
Notes
Improving efficiency
diagram
Farmers can make food production more efficient by restricting the energy that food animals transfer to the environment.
Animals respire to release energy for movement and, in mammals and birds, to keep their body temperature constant. This energy is transferred to the surroundings, and the glucose respired does not become new biomass.
Limiting movement, e.g. keeping animals in pens, cages or sheds, means less energy is used for movement.
Controlling the temperature of the surroundings, e.g. keeping animals in warm sheds, means less energy is transferred to the surroundings to keep warm.
So a greater proportion of the food eaten becomes animal biomass, and the animals grow faster on less food.
Limiting movement and keeping animals warm means less energy is lost, so more food becomes biomass.
Feeding animals high-protein food also makes them grow faster.
Intensive farming
These methods are used in intensive farming of animals such as chickens, pigs and fish.
Advantages: more meat, eggs or fish from less food and less land, so food is cheaper.
Ethical objections
Animals are kept in crowded, restricted spaces and cannot behave naturally, which many people think causes stress and suffering.
Diseases spread quickly between animals kept close together, so antibiotics may be used a lot, which can lead to antibiotic-resistant bacteria.
Heating and lighting the sheds uses a lot of energy, which costs money and may add to carbon dioxide emissions.
Large amounts of animal waste can pollute nearby water.
Some people believe animals should be able to live a natural life, whatever the effect on food prices.
Don’t lose marks
Saying limiting movement means animals 'save energy, so they have more energy'. Say less energy is transferred to the environment, so more of the food becomes biomass.
Saying warm sheds help animals grow because they are 'comfortable'. The reason is that less energy is transferred to keep warm.
Leaving out the ethical objections in 'evaluate' questions, or giving opinions without reasons.
Using the final mass instead of the gain in mass in percentage calculations.
More tips
Memory tricks
Less moving, less heating, more growing.
Energy used to move or keep warm is energy not stored as meat.
Ethical objections, WADE: Welfare, Antibiotics, Disease, Energy costs.
Exam technique
Use the phrase 'less energy is transferred to the environment'; it matches the specification.
In 'evaluate' questions, balance efficiency and food supply against welfare, disease and antibiotics.
Make each link clear: less energy used for movement or warmth, so more biomass, so faster growth.
What each grade needs
What you need to be able to do, from the first marks up to the top grade.
Grade 4
Name ways to make animal farming more efficientLimit the animals' movement, control the temperature of their surroundings, and feed them high-protein food.
Grade 5
Explain why high-protein food increases growthProtein is digested into amino acids, which animals use to make the proteins needed for growth.
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy4 marks
The efficiency of food production from animals can be improved by restricting energy transfer from the animals to the environment.
(a) Which two methods increase the efficiency of food production from animals? Tick (✓) two boxes.[2]
Limiting the movement of the animals
Keeping the animals in cold surroundings
Controlling the temperature of the animals’ surroundings
Letting the animals roam over large areas
(b) Some farm animals are fed high-protein food. Give the reason why.[1]
(c) Give one ethical objection to some modern intensive farming methods.[1]
Show the answer and mark scheme
(a)Answer: Limiting the movement of the animals; Controlling the temperature of the animals’ surroundings
(b)
to increase growth
(c)
animals are kept in cramped conditions / cannot move freely