Evaluating genetic engineering and selective breedingSpec 4.14
In short
Evaluating genetic engineering and selective breeding means weighing up their benefits and risks, including practical and ethical implications, then reaching a judgement. Selective breeding raises yields but takes many generations and reduces genetic variation. Genetic engineering is quicker and can produce medicines such as human insulin, but it has unknown effects and raises ethical concerns.
'Evaluate' means weigh up benefits and risks, including practical and ethical implications, and reach a judgement. Here are the main points for agriculture and medicine.
| Benefits | Risks and implications | |
|---|---|---|
| Selective breeding | Higher yields and better quality food; no special equipment needed; produces useful animals and plants | Takes many generations; reduces genetic variation; inbreeding can cause health problems in animals |
| Genetic engineering in agriculture | Crops with new characteristics such as insect resistance or greater nutritional value; quicker than selective breeding | Unknown effects on the environment and human health; genes may spread to wild species; some people think it is wrong to alter genes |
| Genetic engineering in medicine | Medicines such as human insulin can be made in large amounts from GM organisms | Possible unforeseen effects; ethical concerns about changing the genes of organisms, especially animals |
Practical implications include time, cost, skill and the chance that it does not work. Ethical implications are about what people think is right or wrong, such as animal welfare and whether humans should change the genes of living things.
Interpreting yield data (practice data)
A farmer grows a non-GM crop with a yield of 4.0 tonnes per hectare, and a GM crop with a yield of 5.0 tonnes per hectare. Calculate the percentage increase in yield with the GM crop.
- Increase = 5.0 − 4.0 = 1.0 tonnes per hectare
- Percentage increase = increase ÷ original × 100
- 1.0 ÷ 4.0 × 100 = 25%
Answer: 25% increase.
When asked to plot or read data from graphs or tables, check the axis scales and units, and use values from the data in your evaluation.
In a 6-mark 'evaluate' answer, give benefits and risks, include both practical and ethical points, and finish with a clear conclusion that uses them.
Quick check
What does 'evaluate' require you to do in a question about genetic engineering?
Show answer
Weigh up benefits and risks, including practical and ethical implications, and reach a judgement.
Name one practical and one ethical implication of genetic engineering.
Show answer
Practical: it is costly or may not work. Ethical: some think it is wrong to alter the genes of organisms.
Give one risk of selective breeding.
Show answer
It reduces genetic variation, or inbreeding causes health problems.
Written and checked against the Edexcel GCSE Combined Science (1SC0) specification · Updated October 2026